1
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Yue L, Li J, Yao C, Chen J, Yan C, Wang X, Cao J. Nonequilibrium Lattice Dynamics of Individual and Attached PbSe Quantum Dots under Photoexcitation. J Phys Chem Lett 2024; 15:7667-7673. [PMID: 39037601 DOI: 10.1021/acs.jpclett.4c01541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/23/2024]
Abstract
Quantum dot (QD) solids are emerging materials for many optoelectronic applications. To enhance interdot coupling and charge transport, surface ligands can be removed, allowing individual QDs to be attached along specific crystal orientations (termed "oriented attachment"). Optimizing the electronic and optical properties of QD solids demands a comprehensive understanding of the nanoscale energy flow in individual and attached QDs under photoexcitation. In this work, we employed ultrafast electron diffraction to directly measure how oriented attachment along ⟨100⟩ directions affects the nonequilibrium lattice dynamics of lead selenide QDs. The oriented attachment anisotropically alters the ultrafast energy relaxation along specific crystal axes. Along the ⟨100⟩ directions, both the lattice deformation and atomistic random motions are suppressed in comparison with those of individual QDs. Conversely, the effects are enhanced along the unattached ⟨111⟩ directions due to ligand removal. The oriented attachment switches the major lattice thermalization pathways from ⟨100⟩ to ⟨111⟩ directions.
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Affiliation(s)
- Luye Yue
- Center for Ultrafast Science and Technology, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jingjun Li
- Center for Ultrafast Science and Technology, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Changyuan Yao
- Center for Ultrafast Science and Technology, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jie Chen
- Center for Ultrafast Science and Technology, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chang Yan
- Center for Ultrafast Science and Technology, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
- Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xuan Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Jianming Cao
- Center for Ultrafast Science and Technology, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Physics Department and National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
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2
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Pinna J, Pili E, Mehrabi Koushki R, Gavhane DS, Carlà F, Kooi BJ, Portale G, Loi MA. PbI 2 Passivation of Three Dimensional PbS Quantum Dot Superlattices Toward Optoelectronic Metamaterials. ACS NANO 2024; 18:19124-19136. [PMID: 38954751 PMCID: PMC11271184 DOI: 10.1021/acsnano.4c04076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 06/12/2024] [Accepted: 06/13/2024] [Indexed: 07/04/2024]
Abstract
Lead chalcogenide colloidal quantum dots are one of the most promising materials to revolutionize the field of short-wavelength infrared optoelectronics due to their bandgap tunability and strong absorption. By self-assembling these quantum dots into ordered superlattices, mobilities approaching those of the bulk counterparts can be achieved while still retaining their original optical properties. The recent literature focused mostly on PbSe-based superlattices, but PbS quantum dots have several advantages, including higher stability. In this work, we demonstrate highly ordered 3D superlattices of PbS quantum dots with tunable thickness up to 200 nm and high coherent ordering, both in-plane and along the thickness. We show that we can successfully exchange the ligands throughout the film without compromising the ordering. The superlattices as the active material of an ion gel-gated field-effect transistor achieve electron mobilities up to 220 cm2 V-1 s-1. To further improve the device performance, we performed a postdeposition passivation with PbI2, which noticeably reduced the subthreshold swing making it reach the Boltzmann limit. We believe this is an important proof of concept showing that it is possible to overcome the problem of high trap densities in quantum dot superlattices enabling their application in optoelectronic devices.
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Affiliation(s)
- Jacopo Pinna
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, Groningen 9747 AG, The Netherlands
| | - Elisa Pili
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, Groningen 9747 AG, The Netherlands
| | - Razieh Mehrabi Koushki
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, Groningen 9747 AG, The Netherlands
| | - Dnyaneshwar S. Gavhane
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, Groningen 9747 AG, The Netherlands
| | - Francesco Carlà
- Diamond
House, Harwell Science and Innovation Campus, Diamond Light Source Ltd, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Bart J. Kooi
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, Groningen 9747 AG, The Netherlands
| | - Giuseppe Portale
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, Groningen 9747 AG, The Netherlands
| | - Maria Antonietta Loi
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, Groningen 9747 AG, The Netherlands
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3
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Wach Q, Quick MT, Ayari S, Achtstein AW. Field-dependent THz transport nonlinearities in semiconductor nano structures. Phys Chem Chem Phys 2024; 26:13995-14005. [PMID: 38683165 DOI: 10.1039/d4cp00952e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
Abstract
Charge transport nonlinearities in semiconductor quantum dots and nanorods are studied. Using a density matrix formalism, we retrieve the field-dependent nonlinear mobility and show the possibility of intra-pulse gain. We further demonstrate that the dynamics of master equations can be captured in an analytical formula for the field-dependent charge carrier mobility, e.g. for two-level systems. This equation extends the linear response theory based Kubo-Greenwood result to nonlinear processes at elevated field strength, easily reached in THz transport spectroscopy. With these tools we analyze the field strength, chirp, temperature and dephasing dependence of the charge carrier mobility in the model system of CdSe quantum dots and wires. Stark broadening and Rabi splitting result in strong alterations of the mobility spectra, pronounced at low temperatures. The mobility spectra are strongly temperature and pulse shape dependent in the nonlinear regime. The findings are of immediate interest e.g. for nonlinear THz generation, conversion and amplification in 6G technology and nano electronics. Our results further enable experimentalists to fit and understand measured charge transport nonlinearities with analytical expressions and to design nanosystems with engineered material properties.
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Affiliation(s)
- Quentin Wach
- Institute of Optics and Atomic Physics, Technische Universität Berlin, 10623 Berlin, Germany
| | - Michael T Quick
- Institute of Optics and Atomic Physics, Technische Universität Berlin, 10623 Berlin, Germany
| | - Sabrine Ayari
- Laboratoire de Physique de l'École normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Alexander W Achtstein
- Institute of Optics and Atomic Physics, Technische Universität Berlin, 10623 Berlin, Germany
- Fakultät für Physik, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany.
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4
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Sun K, Xia W, Wang C, Suo P, Zou Y, Peng J, Wang W, Lin X, Jin Z, Guo Y, Ma G. Highly intrinsic carrier mobility in tin diselenide crystal accessed with ultrafast terahertz spectroscopy. OPTICS EXPRESS 2024; 32:17657-17666. [PMID: 38858943 DOI: 10.1364/oe.523383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 04/17/2024] [Indexed: 06/12/2024]
Abstract
Tin diselenide (SnSe2), a layered transition metal dichalcogenide (TMDC), stands out among other TMDCs for its extraordinary photoactive ability and low thermal conductivity. Consequently, it has stimulated many influential researches on photodetectors, ultrafast pulse shaping, thermoelectric devices, etc. However, the carrier mobility in SnSe2, as determined experimentally, remains limited to tens of cm2V-1s-1. This limitation poses a challenge for achieving high-performance SnSe2-based devices. Theoretical calculations, on the other hand, predict that the carrier mobility in SnSe2 can reach hundreds of cm2V-1s-1, approximately one order of magnitude higher than experimental value. Interestingly, the carrier mobility could be underestimated significantly in long-range transportation measurements due to the presence of defects and boundary scattering effects. To address this discrepancy, we employ optic pump terahertz probe spectroscopy to access the photoinduced dynamical THz photoconductivity of SnSe2. Our findings reveal that the intrinsic carrier mobility in conventional SnSe2 single crystal is remarkably high, reaching 353.2 ± 37.7 cm2V-1s-1, consistent with the theoretical prediction. Additionally, dynamical THz photoconductivity measurements reveal that the SnSe2 crystal containing rich defects efficiently capture photoinduced conduction-band electrons and valence-band holes with time constants of ∼20 and ∼200 ps, respectively. Meanwhile, we observe an impulsively stimulated Raman scattering at 0.60 THz. Our study not only demonstrates ultrafast THz spectroscopy as a reliable method for determining intrinsic carrier mobility and detection of low frequency coherent Raman mode in materials but also provides valuable reference for the future application of high-performance SnSe2-based devices.
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5
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Weerdenburg S, Singh N, van der Laan M, Kinge S, Schall P, Siebbeles LDA. New Theoretical Model to Describe Carrier Multiplication in Semiconductors: Explanation of Disparate Efficiency in MoTe 2 versus PbS and PbSe. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2024; 128:3693-3702. [PMID: 38476826 PMCID: PMC10926152 DOI: 10.1021/acs.jpcc.4c00383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 02/16/2024] [Accepted: 02/20/2024] [Indexed: 03/14/2024]
Abstract
We present a theoretical model to compute the efficiency of the generation of two or more electron-hole pairs in a semiconductor by the absorption of one photon via the process of carrier multiplication (CM). The photogeneration quantum yield of electron-hole pairs is calculated from the number of possible CM decay pathways of the electron and the hole. We apply our model to investigate the underlying cause of the high efficiency of CM in bulk 2H-MoTe2, as compared to bulk PbS and PbSe. Electronic band structures were calculated with density functional theory, from which the number of possible CM decay pathways was calculated for all initial electron and hole states that can be produced at a given photon energy. The variation of the number of CM pathways with photon energy reflects the dependence of experimental CM quantum yields on the photon energy and material composition. We quantitatively reproduce experimental CM quantum yields for MoTe2, PbS, and PbSe from the calculated number of CM pathways and one adjustable fit parameter. This parameter is related to the ratio of Coulomb coupling matrix elements and the cooling rate of the electrons and holes. Large variations of this fit parameter result in small changes in the modeled quantum yield for MoTe2, which confirms that its high CM efficiency can be mainly attributed to its extraordinary large number of CM pathways. The methodology of this work can be applied to analyze or predict the CM efficiency of other materials.
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Affiliation(s)
- Sven Weerdenburg
- Chemical
Engineering Department, Delft University
of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands
| | - Nisha Singh
- Chemical
Engineering Department, Delft University
of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands
| | - Marco van der Laan
- Institute
of Physics, University of Amsterdam, Amsterdam 1098 XH, The Netherlands
| | - Sachin Kinge
- Materials
Research & Development, Toyota Motor
Europe, Zaventem B1930, Belgium
| | - Peter Schall
- Institute
of Physics, University of Amsterdam, Amsterdam 1098 XH, The Netherlands
| | - Laurens D. A. Siebbeles
- Chemical
Engineering Department, Delft University
of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands
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6
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Ge F, Han Y, Feng C, Zhang H, Chen F, Xu D, Tao CL, Cheng F, Wu XJ. Halide Ions Regulating the Morphologies of PbS and Au@PbS Core-Shell Nanocrystals: Synthesis, Self-Assembly, and Electrical Transport Properties. J Phys Chem Lett 2023; 14:9521-9530. [PMID: 37851938 DOI: 10.1021/acs.jpclett.3c02614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
The geometry and surface state of nanocrystals (NCs) strongly affect their physiochemical properties, self-assembly behaviors, and potential applications, but there is still a lack of a facile method to regulate the exposed facets of the NCs, especially metal@semiconductor core-shell NCs. Herein, we present a reproducible approach for tuning the morphology of PbS NCs from nanocubes to nano-octahedrons by introducing lead halides as precursors. Excitingly, the method can be easily extended to the synthesis of metal@PbS core-shell NCs with single-crystalline shells and specific exposed facets. In addition, the halide passivation layers on the NCs are found to greatly improve their antioxidant ability. Therefore, the Cl-passivated NCs can self-assemble into atomic-coupled monolayer films via oriented attachment under ambient conditions, which exhibit enhanced electrical conductivities compared with uncoupled counterparts. The precise synthesis of nanocrystals with tunable shapes and the construction of self-assembled films provide a way to expand their application in high-performance optoelectronic devices.
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Affiliation(s)
- Feiyue Ge
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Yingying Han
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Changsheng Feng
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Han Zhang
- State Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Feifan Chen
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Dan Xu
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Chen-Lei Tao
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Fang Cheng
- State Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Xue-Jun Wu
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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7
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Nugraha MI, Indriyati I, Primadona I, Gedda M, Timuda GE, Iskandar F, Anthopoulos TD. Recent Progress in Colloidal Quantum Dot Thermoelectrics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2210683. [PMID: 36857683 DOI: 10.1002/adma.202210683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 02/12/2023] [Indexed: 06/18/2023]
Abstract
Semiconducting colloidal quantum dots (CQDs) represent an emerging class of thermoelectric materials for use in a wide range of future applications. CQDs combine solution processability at low temperatures with the potential for upscalable manufacturing via printing techniques. Moreover, due to their low dimensionality, CQDs exhibit quantum confinement and a high density of grain boundaries, which can be independently exploited to tune the Seebeck coefficient and thermal conductivity, respectively. This unique combination of attractive attributes makes CQDs very promising for application in emerging thermoelectric generator (TEG) technologies operating near room temperature. Herein, recent progress in CQDs for application in emerging thin-film thermoelectrics is reviewed. First, the fundamental concepts of thermoelectricity in nanostructured materials are outlined, followed by an overview of the popular synthetic methods used to produce CQDs with controllable sizes and shapes. Recent strides in CQD-based thermoelectrics are then discussed with emphasis on their application in thin-film TEGs. Finally, the current challenges and future perspectives for further enhancing the performance of CQD-based thermoelectric materials for future applications are discussed.
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Affiliation(s)
- Mohamad Insan Nugraha
- Physical Science and Engineering Division (PSE), KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
- Research Center for Advanced Materials, National Research and Innovation Agency (BRIN), South Tangerang, Banten, 15314, Indonesia
| | - Indriyati Indriyati
- Research Center for Advanced Materials, National Research and Innovation Agency (BRIN), South Tangerang, Banten, 15314, Indonesia
- Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, 40132, Indonesia
| | - Indah Primadona
- Research Center for Advanced Materials, National Research and Innovation Agency (BRIN), South Tangerang, Banten, 15314, Indonesia
- Collaboration Research Center for Advanced Energy Materials, National Research and Innovation Agency - Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, 40135, Indonesia
| | - Murali Gedda
- Physical Science and Engineering Division (PSE), KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Gerald Ensang Timuda
- Research Center for Advanced Materials, National Research and Innovation Agency (BRIN), South Tangerang, Banten, 15314, Indonesia
| | - Ferry Iskandar
- Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, 40132, Indonesia
- Collaboration Research Center for Advanced Energy Materials, National Research and Innovation Agency - Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, 40135, Indonesia
| | - Thomas D Anthopoulos
- Physical Science and Engineering Division (PSE), KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
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8
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Wang C, Chen Z, Liu Z, Ma T, Chen X, Zhang M, Luo D, Hyun BR, Liu X. Adjusting Microscale to Atomic-Scale Structural Order in PbS Nanocrystal Superlattice for Enhanced Photodetector Performance. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2300975. [PMID: 37066743 DOI: 10.1002/smll.202300975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/20/2023] [Indexed: 06/19/2023]
Abstract
An investigation is presented into the effect of the long-range order on the optoelectronic properties of PbS quantum dot (QD) superlattices, which form mesocrystals, for potential use in photodetector applications. By self-assembly of QD nanocrystals on an Si/SiOx substrate, a highly ordered and densely packed PbS QD superlattice with a microscale size is obtained. The results demonstrate that annealing treatment induces mesocrystalline superlattices with preferred growth orientation, achieved by dislodging ligands. The improved orientation and electronic coupling of the mesocrystalline superlattices exhibit superior photodetector performance compared to disordered QD structures and closely packed superlattices. This improved performance is attributed to atomic alignment between QDs, leading to enhanced electronic coupling. The findings suggest that these mesocrystalline superlattices have promising potential for the next generation of QD optoelectronic devices.
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Affiliation(s)
- Chuanglei Wang
- School of Semiconductor Science and Technology, South China Normal University, Guangzhou, 510631, P. R. China
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, Guangzhou, 510631, P. R. China
| | - Zhenjun Chen
- School of Semiconductor Science and Technology, South China Normal University, Guangzhou, 510631, P. R. China
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, Guangzhou, 510631, P. R. China
| | - Zheng Liu
- School of Semiconductor Science and Technology, South China Normal University, Guangzhou, 510631, P. R. China
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, Guangzhou, 510631, P. R. China
| | - Tianchan Ma
- School of Semiconductor Science and Technology, South China Normal University, Guangzhou, 510631, P. R. China
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, Guangzhou, 510631, P. R. China
| | - Xiya Chen
- School of Semiconductor Science and Technology, South China Normal University, Guangzhou, 510631, P. R. China
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, Guangzhou, 510631, P. R. China
| | - Menglong Zhang
- School of Semiconductor Science and Technology, South China Normal University, Guangzhou, 510631, P. R. China
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, Guangzhou, 510631, P. R. China
| | - Dongxiang Luo
- Huangpu Hydrogen Innovation Center/Guangzhou Key Laboratory for Clean Energy and Materials, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou, 510006, P. R. China
| | - Byung-Ryool Hyun
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Xiao Liu
- School of Semiconductor Science and Technology, South China Normal University, Guangzhou, 510631, P. R. China
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, Guangzhou, 510631, P. R. China
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9
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Li D, Chen Q, Chun J, Fichthorn K, De Yoreo J, Zheng H. Nanoparticle Assembly and Oriented Attachment: Correlating Controlling Factors to the Resulting Structures. Chem Rev 2023; 123:3127-3159. [PMID: 36802554 DOI: 10.1021/acs.chemrev.2c00700] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Nanoparticle assembly and attachment are common pathways of crystal growth by which particles organize into larger scale materials with hierarchical structure and long-range order. In particular, oriented attachment (OA), which is a special type of particle assembly, has attracted great attention in recent years because of the wide range of material structures that result from this process, such as one-dimensional (1D) nanowires, two-dimensional (2D) sheets, three-dimensional (3D) branched structures, twinned crystals, defects, etc. Utilizing in situ transmission electron microscopy techniques, researchers observed orientation-specific forces that act over short distances (∼1 nm) from the particle surfaces and drive the OA process. Integrating recently developed 3D fast force mapping via atomic force microscopy with theories and simulations, researchers have resolved the near-surface solution structure, the molecular details of charge states at particle/fluid interfaces, inhomogeneity of surface charges, and dielectric/magnetic properties of particles that influence short- and long-range forces, such as electrostatic, van der Waals, hydration, and dipole-dipole forces. In this review, we discuss the fundamental principles for understanding particle assembly and attachment processes, and the controlling factors and resulting structures. We review recent progress in the field via examples of both experiments and modeling, and discuss current developments and the future outlook.
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Affiliation(s)
- Dongsheng Li
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Qian Chen
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
| | - Jaehun Chun
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
- Levich Institute and Department of Chemical Engineering, CUNY City College of New York; New York, New York 10031, United States
| | - Kristen Fichthorn
- Department of Chemical Engineering, The Pennsylvania State University; University Park, Pennsylvania 16802, United States
| | - James De Yoreo
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
- Department of Materials Science and Engineering, University of Washington, Seattle Washington 98195, United States
| | - Haimei Zheng
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley California 94720, United States
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States
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10
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Cavallo M, Bossavit E, Zhang H, Dabard C, Dang TH, Khalili A, Abadie C, Alchaar R, Mastrippolito D, Prado Y, Becerra L, Rosticher M, Silly MG, Utterback JK, Ithurria S, Avila J, Pierucci D, Lhuillier E. Mapping the Energy Landscape from a Nanocrystal-Based Field Effect Transistor under Operation Using Nanobeam Photoemission Spectroscopy. NANO LETTERS 2023; 23:1363-1370. [PMID: 36692377 DOI: 10.1021/acs.nanolett.2c04637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
As the field of nanocrystal-based optoelectronics matures, more advanced techniques must be developed in order to reveal the electronic structure of nanocrystals, particularly with device-relevant conditions. So far, most of the efforts have been focused on optical spectroscopy, and electrochemistry where an absolute energy reference is required. Device optimization requires probing not only the pristine material but also the material in its actual environment (i.e., surrounded by a transport layer and an electrode, in the presence of an applied electric field). Here, we explored the use of photoemission microscopy as a strategy for operando investigation of NC-based devices. We demonstrate that the method can be applied to a variety of materials and device geometries. Finally, we show that it provides direct access to the metal-semiconductor interface band bending as well as the distance over which the gate effect propagates in field-effect transistors.
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Affiliation(s)
- Mariarosa Cavallo
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, F-75005 Paris, France
| | - Erwan Bossavit
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, F-75005 Paris, France
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, 91190 Saint-Aubin, France
| | - Huichen Zhang
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, F-75005 Paris, France
| | - Corentin Dabard
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI-Paris, PSL Research University, Sorbonne Université Univ Paris 06, CNRS UMR 8213, 10 rue Vauquelin, 75005 Paris, France
| | - Tung Huu Dang
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, F-75005 Paris, France
- Laboratoire de Physique de l'Ecole normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, 75005 Paris, France
| | - Adrien Khalili
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, F-75005 Paris, France
| | - Claire Abadie
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, F-75005 Paris, France
| | - Rodolphe Alchaar
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, F-75005 Paris, France
| | - Dario Mastrippolito
- Department of Physical and Chemical Sciences (DSFC), University of L'Aquila, Via Vetoio, 67100 L'Aquila, Italy
| | - Yoann Prado
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, F-75005 Paris, France
| | - Loïc Becerra
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, F-75005 Paris, France
| | - Michael Rosticher
- Laboratoire de Physique de l'Ecole normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, 75005 Paris, France
| | - Mathieu G Silly
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, 91190 Saint-Aubin, France
| | - James K Utterback
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, F-75005 Paris, France
| | - Sandrine Ithurria
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI-Paris, PSL Research University, Sorbonne Université Univ Paris 06, CNRS UMR 8213, 10 rue Vauquelin, 75005 Paris, France
| | - José Avila
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, 91190 Saint-Aubin, France
| | - Debora Pierucci
- Centre de Nanosciences et de Nanotechnologies, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - Emmanuel Lhuillier
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, F-75005 Paris, France
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11
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Pinna J, Mehrabi Koushki R, Gavhane DS, Ahmadi M, Mutalik S, Zohaib M, Protesescu L, Kooi BJ, Portale G, Loi MA. Approaching Bulk Mobility in PbSe Colloidal Quantum Dots 3D Superlattices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2207364. [PMID: 36308048 DOI: 10.1002/adma.202207364] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 10/13/2022] [Indexed: 06/16/2023]
Abstract
3D superlattices made of colloidal quantum dots are a promising candidate for the next generation of optoelectronic devices as they are expected to exhibit a unique combination of tunable optical properties and coherent electrical transport through minibands. While most of the previous work was performed on 2D arrays, the control over the formation of these systems is lacking, where limited long-range order and energetical disorder have so far hindered the potential of these metamaterials, giving rise to disappointing transport properties. Here, it is reported that nanoscale-level controlled ordering of colloidal quantum dots in 3D and over large areas allows the achievement of outstanding transport properties. The measured electron mobilities are the highest ever reported for a self-assembled solid of fully quantum-confined objects. This ultimately demonstrates that optoelectronic metamaterials with highly tunable optical properties (in this case in the short-wavelength infrared spectral range) and charge mobilities approaching that of bulk semiconductor can be obtained. This finding paves the way toward a new generation of optoelectronic devices.
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Affiliation(s)
- Jacopo Pinna
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh, 4, Groningen, 9747 AG, The Netherlands
| | - Razieh Mehrabi Koushki
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh, 4, Groningen, 9747 AG, The Netherlands
| | - Dnyaneshwar S Gavhane
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh, 4, Groningen, 9747 AG, The Netherlands
| | - Majid Ahmadi
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh, 4, Groningen, 9747 AG, The Netherlands
| | - Suhas Mutalik
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh, 4, Groningen, 9747 AG, The Netherlands
| | - Muhammad Zohaib
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh, 4, Groningen, 9747 AG, The Netherlands
| | - Loredana Protesescu
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh, 4, Groningen, 9747 AG, The Netherlands
| | - Bart J Kooi
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh, 4, Groningen, 9747 AG, The Netherlands
| | - Giuseppe Portale
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh, 4, Groningen, 9747 AG, The Netherlands
| | - Maria Antonietta Loi
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh, 4, Groningen, 9747 AG, The Netherlands
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12
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Abelson A, Qian C, Crawford Z, Zimanyi GT, Law M. High-Mobility Hole Transport in Single-Grain PbSe Quantum Dot Superlattice Transistors. NANO LETTERS 2022; 22:9578-9585. [PMID: 36411037 PMCID: PMC9756332 DOI: 10.1021/acs.nanolett.2c03657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 11/14/2022] [Indexed: 06/16/2023]
Abstract
Epitaxially-fused superlattices of colloidal quantum dots (QD epi-SLs) may exhibit electronic minibands and high-mobility charge transport, but electrical measurements of epi-SLs have been limited to large-area, polycrystalline samples in which superlattice grain boundaries and intragrain defects suppress/obscure miniband effects. Systematic measurements of charge transport in individual, highly-ordered epi-SL grains would facilitate the study of minibands in QD films. Here, we demonstrate the air-free fabrication of microscale field-effect transistors (μ-FETs) with channels consisting of single PbSe QD epi-SL grains (2-7 μm channel dimensions) and analyze charge transport in these single-grain devices. The eight devices studied show p-channel or ambipolar transport with a hole mobility as high as 3.5 cm2 V-1 s-1 at 290 K and 6.5 cm2 V-1 s-1 at 170-220 K, one order of magnitude larger than that of previous QD solids. The mobility peaks at 150-220 K, but device hysteresis at higher temperatures makes the true mobility-temperature curve uncertain and evidence for miniband transport inconclusive.
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Affiliation(s)
- Alex Abelson
- Department
of Materials Science and Engineering, University
of California, Irvine, Irvine, California 92697, United States
| | - Caroline Qian
- Department
of Chemical and Biomolecular Engineering, University of California, Irvine, Irvine, California 92697, United States
| | - Zachary Crawford
- Department
of Physics, University of California, Davis, Davis, California 95616, United States
| | - Gergely T. Zimanyi
- Department
of Physics, University of California, Davis, Davis, California 95616, United States
| | - Matt Law
- Department
of Materials Science and Engineering, University
of California, Irvine, Irvine, California 92697, United States
- Department
of Chemical and Biomolecular Engineering, University of California, Irvine, Irvine, California 92697, United States
- Department
of Chemistry, University of California,
Irvine, Irvine, California 92697, United States
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13
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Wang B, Zhong X, Xu H, Zhang Y, Cvelbar U, Ostrikov K(K. Structure and Photoluminescence of WO 3-x Aggregates Tuned by Surfactants. MICROMACHINES 2022; 13:2075. [PMID: 36557374 PMCID: PMC9785493 DOI: 10.3390/mi13122075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/18/2022] [Accepted: 11/23/2022] [Indexed: 06/17/2023]
Abstract
The optoelectronic properties of transition metal oxide semiconductors depend on their oxygen vacancies, nanostructures and aggregation states. Here, we report the synthesis and photoluminescence (PL) properties of substoichiometric tungsten oxide (WO3-x) aggregates with the nanorods, nanoflakes, submicro-spherical-like, submicro-spherical and micro-spherical structures in the acetic acid solution without and with the special surfactants (butyric or oleic acids). Based on theory on the osmotic potential of polymers, we demonstrate the structural change of the WO3-x aggregates, which is related to the change of steric repulsion caused by the surfactant layers, adsorption and deformation of the surfactant molecules on the WO3-x nanocrystals. The WO3-x aggregates generate multi-color light, including ultraviolet, blue, green, red and near-infrared light caused by the inter-band transition and defect level-specific transition as well as the relaxation of polarons. Compared to the nanorod and nanoflake WO3-x aggregates, the PL quenching of the submicro-spherical-like, submicro-spherical and micro-spherical WO3-x aggregates is associated with the coupling between the WO3-x nanoparticles and the trapping centers arising from the surfactant molecules adsorbed on the WO3-x nanoparticles.
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Affiliation(s)
- Biben Wang
- College of Chemistry and Chemical Engineering, Chongqing University of Technology, 69 Hongguang Rd, Lijiatuo, Banan District, Chongqing 400054, China
| | - Xiaoxia Zhong
- State Key Laboratory of Advanced Optical Communication and Networks, Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Haiyan Xu
- School of Materials and Chemical Engineering, Anhui Jianzhu University, Hefei 230601, China
| | - Yongcai Zhang
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225009, China
| | - Uros Cvelbar
- Jozef Stefan Institute, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia
| | - Kostya (Ken) Ostrikov
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4000, Australia
- Centre for Materials Science, Queensland University of Technology, Brisbane, QLD 4000, Australia
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14
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Grimaldi D, Kelderer E, Dirin DN, Kovalenko MV, Hohenau A, Ditlbacher H, Krenn JR. Photoconductivity of PbS/perovskite quantum dots in gold nanogaps. NANOSCALE ADVANCES 2022; 4:3566-3572. [PMID: 36134347 PMCID: PMC9400517 DOI: 10.1039/d2na00284a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 07/17/2022] [Indexed: 06/15/2023]
Abstract
We demonstrate that the photoconductance of colloidal PbS/MAPbI3 quantum dots in nanoscale gold electrode gaps shows a consistent power law dependence of the photocurrent on the light intensity with an exponent slightly below 0.7. The gap sizes are between 25 and 800 nm and by scanning photocurrent microscopy we evidence the strong localization and high reproducibility of photocurrent generation. We probe different flat-faced and pointed electrodes for excitation light in the red and near infrared spectral range and laser irradiances from 10-2 to 102 W cm-2. Our material combination provides practically identical photocurrent response for a wide range of gap sizes and geometries, highlighting its generic potential for nanoscale light coupling and detection.
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Affiliation(s)
- Dario Grimaldi
- Institute of Physics, University of Graz 8010 Graz Austria
| | - Emil Kelderer
- Institute of Physics, University of Graz 8010 Graz Austria
| | - Dmitry N Dirin
- Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich 8093 Zürich Switzerland
- Empa - Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Thin Films and Photovoltaics 8600 Dübendorf Switzerland
| | - Maksym V Kovalenko
- Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich 8093 Zürich Switzerland
- Empa - Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Thin Films and Photovoltaics 8600 Dübendorf Switzerland
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15
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Jasrasaria D, Weinberg D, Philbin JP, Rabani E. Simulations of nonradiative processes in semiconductor nanocrystals. J Chem Phys 2022; 157:020901. [PMID: 35840368 DOI: 10.1063/5.0095897] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The description of carrier dynamics in spatially confined semiconductor nanocrystals (NCs), which have enhanced electron-hole and exciton-phonon interactions, is a great challenge for modern computational science. These NCs typically contain thousands of atoms and tens of thousands of valence electrons with discrete spectra at low excitation energies, similar to atoms and molecules, that converge to the continuum bulk limit at higher energies. Computational methods developed for molecules are limited to very small nanoclusters, and methods for bulk systems with periodic boundary conditions are not suitable due to the lack of translational symmetry in NCs. This perspective focuses on our recent efforts in developing a unified atomistic model based on the semiempirical pseudopotential approach, which is parameterized by first-principle calculations and validated against experimental measurements, to describe two of the main nonradiative relaxation processes of quantum confined excitons: exciton cooling and Auger recombination. We focus on the description of both electron-hole and exciton-phonon interactions in our approach and discuss the role of size, shape, and interfacing on the electronic properties and dynamics for II-VI and III-V semiconductor NCs.
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Affiliation(s)
- Dipti Jasrasaria
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Daniel Weinberg
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - John P Philbin
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Eran Rabani
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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16
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Ballabio M, Cánovas E. Electron Transfer at Quantum Dot–Metal Oxide Interfaces for Solar Energy Conversion. ACS NANOSCIENCE AU 2022; 2:367-395. [PMID: 36281255 PMCID: PMC9585894 DOI: 10.1021/acsnanoscienceau.2c00015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Electron transfer
at a donor–acceptor quantum dot–metal
oxide interface is a process fundamentally relevant to solar energy
conversion architectures as, e.g., sensitized solar cells and solar
fuels schemes. As kinetic competition at these technologically relevant
interfaces largely determines device performance, this Review surveys
several aspects linking electron transfer dynamics and device efficiency;
this correlation is done for systems aiming for efficiencies up to
and above the ∼33% efficiency limit set by Shockley and Queisser
for single gap devices. Furthermore, we critically comment on common
pitfalls associated with the interpretation of kinetic data obtained
from current methodologies and experimental approaches, and finally,
we highlight works that, to our judgment, have contributed to a better
understanding of the fundamentals governing electron transfer at quantum
dot–metal oxide interfaces.
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Affiliation(s)
- Marco Ballabio
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia), 28049 Madrid, Spain
| | - Enrique Cánovas
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia), 28049 Madrid, Spain
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17
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Freeney SE, Slot MR, Gardenier TS, Swart I, Vanmaekelbergh D. Electronic Quantum Materials Simulated with Artificial Model Lattices. ACS NANOSCIENCE AU 2022; 2:198-224. [PMID: 35726276 PMCID: PMC9204828 DOI: 10.1021/acsnanoscienceau.1c00054] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 01/24/2022] [Accepted: 01/28/2022] [Indexed: 11/29/2022]
Abstract
![]()
The
band structure and electronic properties of a material are
defined by the sort of elements, the atomic registry in the crystal,
the dimensions, the presence of spin–orbit coupling, and the
electronic interactions. In natural crystals, the interplay of these
factors is difficult to unravel, since it is usually not possible
to vary one of these factors in an independent way, keeping the others
constant. In other words, a complete understanding of complex electronic
materials remains challenging to date. The geometry of two- and one-dimensional
crystals can be mimicked in artificial lattices. Moreover, geometries
that do not exist in nature can be created for the sake of further
insight. Such engineered artificial lattices can be better controlled
and fine-tuned than natural crystals. This makes it easier to vary
the lattice geometry, dimensions, spin–orbit coupling, and
interactions independently from each other. Thus, engineering and
characterization of artificial lattices can provide unique insights.
In this Review, we focus on artificial lattices that are built atom-by-atom
on atomically flat metals, using atomic manipulation in a scanning
tunneling microscope. Cryogenic scanning tunneling microscopy allows
for consecutive creation, microscopic characterization, and band-structure
analysis by tunneling spectroscopy, amounting in the analogue quantum
simulation of a given lattice type. We first review the physical elements
of this method. We then discuss the creation and characterization
of artificial atoms and molecules. For the lattices, we review works
on honeycomb and Lieb lattices and lattices that result in crystalline
topological insulators, such as the Kekulé and “breathing”
kagome lattice. Geometric but nonperiodic structures such as electronic
quasi-crystals and fractals are discussed as well. Finally, we consider
the option to transfer the knowledge gained back to real materials,
engineered by geometric patterning of semiconductor quantum wells.
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Affiliation(s)
- Saoirsé E. Freeney
- Condensed Matter and Interfaces, Debye Institute of Nanomaterial Science, University of Utrecht, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Marlou R. Slot
- Condensed Matter and Interfaces, Debye Institute of Nanomaterial Science, University of Utrecht, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Thomas S. Gardenier
- Condensed Matter and Interfaces, Debye Institute of Nanomaterial Science, University of Utrecht, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Ingmar Swart
- Condensed Matter and Interfaces, Debye Institute of Nanomaterial Science, University of Utrecht, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Daniel Vanmaekelbergh
- Condensed Matter and Interfaces, Debye Institute of Nanomaterial Science, University of Utrecht, Princetonplein 5, 3584 CC Utrecht, The Netherlands
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18
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Notot V, Walravens W, Berthe M, Peric N, Addad A, Wallart X, Delerue C, Hens Z, Grandidier B, Biadala L. Quantum Dot Acceptors in Two-Dimensional Epitaxially Fused PbSe Quantum Dot Superlattices. ACS NANO 2022; 16:3081-3091. [PMID: 35156366 DOI: 10.1021/acsnano.1c10596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Oriented attachment of colloidal quantum dots allows the growth of two-dimensional crystals by design, which could have striking electronic properties upon progress on manipulating their conductivity. Here, we explore the origin of doping in square and epitaxially fused PbSe quantum dot superlattices with low-temperature scanning tunneling microscopy and spectroscopy. Probing the density of states of numerous individual quantum dots reveals an electronic coupling between the hole ground states of the quantum dots. Moreover, a small amount of quantum dots shows a reproducible deep level in the band gap, which is not caused by structural defects in the connections but arises from unpassivated sites at the {111} facets. Based on semiconductor statistics, these distinct defective quantum dots, randomly distributed in the superlattice, trap electrons, releasing a concentration of free holes, which is intimately related to the interdot electronic coupling. They act as acceptor quantum dots in the host quantum dot lattice, mimicking the role of dopant atoms in a semiconductor crystal.
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Affiliation(s)
- Vincent Notot
- Université Lille, CNRS, Centrale Lille, Université Polytechnique Hauts-de-France, JUNIA-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - Willem Walravens
- Physics and Chemistry of Nanostructures, Ghent University, 9000 Ghent, Belgium
| | - Maxime Berthe
- Université Lille, CNRS, Centrale Lille, Université Polytechnique Hauts-de-France, JUNIA-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - Nemanja Peric
- Université Lille, CNRS, Centrale Lille, Université Polytechnique Hauts-de-France, JUNIA-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - Ahmed Addad
- Université Lille, CNRS, INRAE, Centrale Lille, UMR 8207 - UMET - Unité Matériaux et Transformations, F-59000 Lille, France
| | - Xavier Wallart
- Université Lille, CNRS, Centrale Lille, Université Polytechnique Hauts-de-France, JUNIA-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - Christophe Delerue
- Université Lille, CNRS, Centrale Lille, Université Polytechnique Hauts-de-France, JUNIA-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - Zeger Hens
- Physics and Chemistry of Nanostructures, Ghent University, 9000 Ghent, Belgium
| | - Bruno Grandidier
- Université Lille, CNRS, Centrale Lille, Université Polytechnique Hauts-de-France, JUNIA-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - Louis Biadala
- Université Lille, CNRS, Centrale Lille, Université Polytechnique Hauts-de-France, JUNIA-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
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19
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Korath Shivan S, Maier A, Scheele M. Emergent properties in supercrystals of atomically precise nanoclusters and colloidal nanocrystals. Chem Commun (Camb) 2022; 58:6998-7017. [DOI: 10.1039/d2cc00778a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We provide a comprehensive account of the optical, electrical and mechanical properties that result from the self-assembly of colloidal nanocrystals or atomically precise nanoclusters into crystalline arrays with long-range order....
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20
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Ma J, Chen M, Qiao S, Fu G, Wang S. High-performance broadband position-sensitive detector based on lateral photovoltaic effect of PbSe heterostructure. OPTICS EXPRESS 2021; 29:35226-35237. [PMID: 34808961 DOI: 10.1364/oe.439796] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 09/29/2021] [Indexed: 06/13/2023]
Abstract
PbSe has attracted considerable attention due to its promising applications in optoelectronics and energy harvesting. In this work, we explore the lateral photovoltaic effect (LPE) of PbSe films with a simple PbSe/Si heterostructure under nonuniform light illumination and zero-bias conditions. The LPE response is strongly dependent on the thickness of the PbSe film, but always shows a linear dependence on the laser spot position in an ultra-large working size of 5 mm and exhibits a wide photoresponse ranging from visible to near-infrared. The maximum position sensitivity can reach up to 190 mV/mm for the 15-nm-thick PbSe device at 1064 nm and nonlinearity is less than 4%, demonstrating its new potential application in novel position sensitive detectors (PSDs). Besides, the device also shows an ultrafast response speed, with the rise and fall time of ∼40 µs and ∼105 µs, respectively, and excellent reproducibility. These results bring great inspirations for developing high-performance broadband and self-powered PSDs based on the PbSe/Si heterostructure.
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21
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Quick MT, Owschimikow N, Achtstein AW. Terahertz Charge Carrier Mobility in 1D and 2D Semiconductor Nanoparticles. J Phys Chem Lett 2021; 12:7688-7695. [PMID: 34378384 DOI: 10.1021/acs.jpclett.1c02045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We investigate the charge carrier mobility in 1D and 2D semiconductor nanoparticle domains with a focus on the interpretation of THz mobility measurements. We provide a microscopic understanding of the frequency-dependent charge carrier transport in these structures of finite lateral size. Yet unexplored oscillations in the frequency-dependent complex conductivity and a strong size dependence of the mobility are observed. The quantum nature of the charge carrier states results in oscillations in the frequency-dependent mobility for subresonant THz probing, seen in experiments. The effect is based on the lack of an energy continuum for the charge motion. In 2D systems the mobility is further governed by transitions in the two orthogonal x- and y-directions and depends nontrivially on the THz polarization, as well as the quantum well lateral aspect ratio, defining the energetic detuning of the lowest THz-photon transitions in both directions. We analyze the frequency, length, and effective mass dependencies.
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Affiliation(s)
- Michael T Quick
- Institute of Optics and Atomic Physics, Technical University of Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Nina Owschimikow
- Institute of Optics and Atomic Physics, Technical University of Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Alexander W Achtstein
- Institute of Optics and Atomic Physics, Technical University of Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
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22
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Liu J, Enomoto K, Takeda K, Inoue D, Pu YJ. Simple cubic self-assembly of PbS quantum dots by finely controlled ligand removal through gel permeation chromatography. Chem Sci 2021; 12:10354-10361. [PMID: 34377421 PMCID: PMC8336479 DOI: 10.1039/d1sc02096j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 07/05/2021] [Indexed: 11/21/2022] Open
Abstract
The geometry in self-assembled superlattices of colloidal quantum dots (QDs) strongly affects their optoelectronic properties and is thus of critical importance for applications in optoelectronic devices. Here, we achieve the selective control of the geometry of colloidal quasi-spherical PbS QDs in highly-ordered two and three dimensional superlattices: Disordered, simple cubic (sc), and face-centered cubic (fcc). Gel permeation chromatography (GPC), not based on size-exclusion effects, is developed to quantitatively and continuously control the ligand coverage of PbS QDs. The obtained QDs can retain their high stability and photoluminescence on account of the chemically soft removal of the ligands by GPC. With increasing ligand coverage, the geometry of the self-assembled superlattices by solution-casting of the GPC-processed PbS QDs changed from disordered, sc to fcc because of the finely controlled ligand coverage and anisotropy on QD surfaces. Importantly, the highly-ordered sc supercrystal usually displays unique superfluorescence and is expected to show high charge transporting properties, but it has not yet been achieved for colloidal quasi-spherical QDs. It is firstly accessible by fine-tuning the QD ligand density using the GPC method here. This selective formation of different geometric superlattices based on GPC promises applications of such colloidal quasi-spherical QDs in high-performance optoelectronic devices.
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Affiliation(s)
- Jianjun Liu
- RIKEN Center for Emergent Matter Science (CEMS) Wako Saitama 351-0198 Japan
| | - Kazushi Enomoto
- RIKEN Center for Emergent Matter Science (CEMS) Wako Saitama 351-0198 Japan
| | - Kotaro Takeda
- RIKEN Center for Emergent Matter Science (CEMS) Wako Saitama 351-0198 Japan
| | - Daishi Inoue
- RIKEN Center for Emergent Matter Science (CEMS) Wako Saitama 351-0198 Japan
| | - Yong-Jin Pu
- RIKEN Center for Emergent Matter Science (CEMS) Wako Saitama 351-0198 Japan
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23
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Purschke DN, Pielmeier MRP, Üzer E, Ott C, Jensen C, Degg A, Vogel A, Amer N, Nilges T, Hegmann FA. Ultrafast Photoconductivity and Terahertz Vibrational Dynamics in Double-Helix SnIP Nanowires. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2100978. [PMID: 34278600 DOI: 10.1002/adma.202100978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/30/2021] [Indexed: 06/13/2023]
Abstract
Tin iodide phosphide (SnIP), an inorganic double-helix material, is a quasi-1D van der Waals semiconductor that shows promise in photocatalysis and flexible electronics. However, the understanding of the fundamental photophysics and charge transport dynamics of this new material is limited. Here, time-resolved terahertz (THz) spectroscopy is used to probe the transient photoconductivity of SnIP nanowire films and measure the carrier mobility. With insight into the highly anisotropic electronic structure from quantum chemical calculations, an electron mobility as high as 280 cm2 V-1 s-1 along the double-helix axis and a hole mobility of 238 cm2 V-1 s-1 perpendicular to the double-helix axis are detected. Additionally, infrared-active (IR-active) THz vibrational modes are measured, which shows excellent agreement with first-principles calculations, and an ultrafast photoexcitation-induced charge redistribution is observed that reduces the amplitude of a twisting mode of the outer SnI helix on picosecond timescales. Finally, it is shown that the carrier lifetime and mobility are limited by a trap density greater than 1018 cm-3 . The results provide insight into the optical excitation and relaxation pathways of SnIP and demonstrate a remarkably high carrier mobility for such a soft and flexible material, suggesting that it could be ideally suited for flexible electronics applications.
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Affiliation(s)
- David N Purschke
- Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
| | - Markus R P Pielmeier
- Department of Chemistry, Technical University of Munich, 85748, Garching bei München, Germany
| | - Ebru Üzer
- Department of Chemistry, Technical University of Munich, 85748, Garching bei München, Germany
| | - Claudia Ott
- Department of Chemistry, Technical University of Munich, 85748, Garching bei München, Germany
| | - Charles Jensen
- Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
| | - Annabelle Degg
- Department of Chemistry, Technical University of Munich, 85748, Garching bei München, Germany
| | - Anna Vogel
- Department of Chemistry, Technical University of Munich, 85748, Garching bei München, Germany
| | - Naaman Amer
- Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
| | - Tom Nilges
- Department of Chemistry, Technical University of Munich, 85748, Garching bei München, Germany
| | - Frank A Hegmann
- Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
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24
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Capiod P, van der Sluijs M, de Boer J, Delerue C, Swart I, Vanmaekelbergh D. Electronic properties of atomically coherent square PbSe nanocrystal superlattice resolved by Scanning Tunneling Spectroscopy. NANOTECHNOLOGY 2021; 32:325706. [PMID: 33930872 DOI: 10.1088/1361-6528/abfd57] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 04/30/2021] [Indexed: 06/12/2023]
Abstract
Rock-salt lead selenide nanocrystals can be used as building blocks for large scale square superlattices via two-dimensional assembly of nanocrystals at a liquid-air interface followed by oriented attachment. Here we report Scanning Tunneling Spectroscopy measurements of the local density of states of an atomically coherent superlattice with square geometry made from PbSe nanocrystals. Controlled annealing of the sample permits the imaging of a clean structure and to reproducibly probe the band gap and the valence hole and conduction electron states. The measured band gap and peak positions are compared to the results of optical spectroscopy and atomistic tight-binding calculations of the square superlattice band structure. In spite of the crystalline connections between nanocrystals that induce significant electronic couplings, the electronic structure of the superlattices remains very strongly influenced by the effects of disorder and variability.
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Affiliation(s)
- Pierre Capiod
- Debye Institute for Nanomaterials Science, Utrecht University, PO Box 80 000, 3508 TA Utrecht, The Netherlands
| | - Maaike van der Sluijs
- Debye Institute for Nanomaterials Science, Utrecht University, PO Box 80 000, 3508 TA Utrecht, The Netherlands
| | - Jeroen de Boer
- Debye Institute for Nanomaterials Science, Utrecht University, PO Box 80 000, 3508 TA Utrecht, The Netherlands
| | - Christophe Delerue
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia, UMR 8520-IEMN, F-59000 Lille, France
| | - Ingmar Swart
- Debye Institute for Nanomaterials Science, Utrecht University, PO Box 80 000, 3508 TA Utrecht, The Netherlands
| | - Daniel Vanmaekelbergh
- Debye Institute for Nanomaterials Science, Utrecht University, PO Box 80 000, 3508 TA Utrecht, The Netherlands
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25
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Zhao Q, Gouget G, Guo J, Yang S, Zhao T, Straus DB, Qian C, Oh N, Wang H, Murray CB, Kagan CR. Enhanced Carrier Transport in Strongly Coupled, Epitaxially Fused CdSe Nanocrystal Solids. NANO LETTERS 2021; 21:3318-3324. [PMID: 33792310 DOI: 10.1021/acs.nanolett.1c00860] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Strongly coupled, epitaxially fused colloidal nanocrystal (NC) solids are promising solution-processable semiconductors to realize optoelectronic devices with high carrier mobilities. Here, we demonstrate sequential, solid-state cation exchange reactions to transform epitaxially connected PbSe NC thin films into Cu2Se nanostructured thin-film intermediates and then successfully to achieve zinc-blende, CdSe NC solids with wide epitaxial necking along {100} facets. Transient photoconductivity measurements probe carrier transport at nanometer length scales and show a photoconductance of 0.28(1) cm2 V-1 s-1, the highest among CdSe NC solids reported. Atomic-layer deposition of a thin Al2O3 layer infiltrates and protects the structure from fusing into a polycrystalline thin film during annealing and further improves the photoconductance to 1.71(5) cm2 V-1 s-1 and the diffusion length to 760 nm. We fabricate field-effect transistors to study carrier transport at micron length scales and realize high electron mobilities of 35(3) cm2 V-1 s-1 with on-off ratios of 106 after doping.
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26
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Gréboval C, Chu A, Goubet N, Livache C, Ithurria S, Lhuillier E. Mercury Chalcogenide Quantum Dots: Material Perspective for Device Integration. Chem Rev 2021; 121:3627-3700. [DOI: 10.1021/acs.chemrev.0c01120] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Charlie Gréboval
- CNRS, Institut des NanoSciences de Paris, INSP, Sorbonne Université, F-75005 Paris, France
| | - Audrey Chu
- CNRS, Institut des NanoSciences de Paris, INSP, Sorbonne Université, F-75005 Paris, France
| | - Nicolas Goubet
- CNRS, Laboratoire de la Molécule aux Nano-objets; Réactivité, Interactions et Spectroscopies, MONARIS, Sorbonne Université, 4 Place Jussieu, Case Courier 840, F-75005 Paris, France
| | - Clément Livache
- CNRS, Institut des NanoSciences de Paris, INSP, Sorbonne Université, F-75005 Paris, France
| | - Sandrine Ithurria
- Laboratoire de Physique et d’Etude des Matériaux, ESPCI-Paris, PSL Research University, Sorbonne Université Univ Paris 06, CNRS UMR 8213, 10 rue Vauquelin 75005 Paris, France
| | - Emmanuel Lhuillier
- CNRS, Institut des NanoSciences de Paris, INSP, Sorbonne Université, F-75005 Paris, France
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27
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Ondry JC, Philbin JP, Lostica M, Rabani E, Alivisatos AP. Colloidal Synthesis Path to 2D Crystalline Quantum Dot Superlattices. ACS NANO 2021; 15:2251-2262. [PMID: 33377761 DOI: 10.1021/acsnano.0c07202] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
By combining colloidal nanocrystal synthesis, self-assembly, and solution phase epitaxial growth techniques, we developed a general method for preparing single dot thick atomically attached quantum dot (QD) superlattices with high-quality translational and crystallographic orientational order along with state-of-the-art uniformity in the attachment thickness. The procedure begins with colloidal synthesis of hexagonal prism shaped core/shell QDs (e.g., CdSe/CdS), followed by liquid subphase self-assembly and immobilization of superlattices on a substrate. Solution phase epitaxial growth of additional semiconductor material fills in the voids between the particles, resulting in a QD-in-matrix structure. The photoluminescence emission spectra of the QD-in-matrix structure retains characteristic 0D electronic confinement. Importantly, annealing of the resulting structures removes inhomogeneities in the QD-QD inorganic bridges, which our atomistic electronic structure calculations demonstrate would otherwise lead to Anderson-type localization. The piecewise nature of this procedure allows one to independently tune the size and material of the QD core, shell, QD-QD distance, and the matrix material. These four choices can be tuned to control many properties (degree of quantum confinement, quantum coupling, band alignments, etc.) depending on the specific applications. Finally, cation exchange reactions can be performed on the final QD-in-matrix, as demonstrated herein with a CdSe/CdS to HgSe/HgS conversion.
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Affiliation(s)
- Justin C Ondry
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Kavli Energy NanoScience Institute, Berkeley, California 94720, United States
| | - John P Philbin
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Michael Lostica
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Eran Rabani
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv, Israel 69978
| | - A Paul Alivisatos
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Kavli Energy NanoScience Institute, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States
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28
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Salzmann BV, van der Sluijs MM, Soligno G, Vanmaekelbergh D. Oriented Attachment: From Natural Crystal Growth to a Materials Engineering Tool. Acc Chem Res 2021; 54:787-797. [PMID: 33502844 PMCID: PMC7893701 DOI: 10.1021/acs.accounts.0c00739] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Indexed: 12/18/2022]
Abstract
ConspectusIntuitively, chemists see crystals grow atom-by-atom or molecule-by-molecule, very much like a mason builds a wall, brick by brick. It is much more difficult to grasp that small crystals can meet each other in a liquid or at an interface, start to align their crystal lattices and then grow together to form one single crystal. In analogy, that looks more like prefab building. Yet, this is what happens in many occasions and can, with reason, be considered as an alternative mechanism of crystal growth. Oriented attachment is the process in which crystalline colloidal particles align their atomic lattices and grow together into a single crystal. Hence, two aligned crystals become one larger crystal by epitaxy of two specific facets, one of each crystal. If we simply consider the system of two crystals, the unifying attachment reduces the surface energy and results in an overall lower (free) energy of the system. Oriented attachment often occurs with massive numbers of crystals dispersed in a liquid phase, a sol or crystal suspension. In that case, oriented attachment lowers the total free energy of the crystal suspension, predominantly by removal of the nanocrystal/liquid interface area. Accordingly, we should start by considering colloidal suspensions with crystals as the dispersed phase, i.e., "sols", and discuss the reasons for their thermodynamic (meta)stability and how this stability can be lowered such that oriented attachment can occur as a spontaneous thermodynamic process. Oriented attachment is a process observed both for charge-stabilized crystals in polar solvents and for ligand capped nanocrystal suspensions in nonpolar solvents. In this last system different facets can develop a very different reactivity for oriented attachment. Due to this facet selectivity, crystalline structures with very specific geometries can be grown in one, two, or three dimensions; controlled oriented attachment suddenly becomes a tool for material scientists to grow architectures that cannot be reached by any other means. We will review the work performed with PbSe and CdSe nanocrystals. The entire process, i.e., the assembly of nanocrystals, atomic alignment, and unification by attachment, is a very complex and intriguing process. Researchers have succeeded in monitoring these different steps with in situ wave scattering methods and real-space (S)TEM studies. At the same time coarse-grained molecular dynamics simulations have been used to further study the forces involved in self-assembly and attachment at an interface. We will briefly come back to some of these results in the last sections of this review.
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Affiliation(s)
| | | | - Giuseppe Soligno
- Condensed Matter and Interfaces,
Debye Institute for Nanomaterials Science, Utrecht University, P. O. Box 80000, 3508 TA Utrecht, The Netherlands
| | - Daniel Vanmaekelbergh
- Condensed Matter and Interfaces,
Debye Institute for Nanomaterials Science, Utrecht University, P. O. Box 80000, 3508 TA Utrecht, The Netherlands
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29
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Smeaton MA, El Baggari I, Balazs DM, Hanrath T, Kourkoutis LF. Mapping Defect Relaxation in Quantum Dot Solids upon In Situ Heating. ACS NANO 2021; 15:719-726. [PMID: 33444506 DOI: 10.1021/acsnano.0c06990] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Epitaxially connected quantum dot solids have emerged as an interesting class of quantum confined materials with the potential for highly tunable electronic structures. Realization of the predicted emergent electronic properties has remained elusive due in part to defective interdot epitaxial connections. Thermal annealing has shown potential to eliminate such defects, but a direct understanding of this mechanism hinges on determining the nature of defects in the connections and how they respond to heating. Here, we use in situ heating in the scanning transmission electron microscope to probe the effect of heating on distinct defect types. We apply a real space, local strain mapping technique, which allows us to identify tensile and shear strain in the atomic lattice, highlighting tensile, shear, and bending defects in interdot connections. We also track the out-of-plane orientation of individual QDs and infer the prevalence of out-of-plane twisting and bending defects as a function of annealing. We find that tensile and shear defects are fully relaxed upon mild thermal annealing, while bending defects persist. Additionally, out-of-plane orientation tracking reveals an increase in correctly oriented QDs, pointing to a relaxation of either twisting defects or out-of-plane bending defects. While bending defects remain, highlighting the need for further study of orientational ordering during the preattachment phase of superlattice formation, these atomic-scale insights show that annealing can effectively eliminate tensile and shear defects, a promising step toward delocalization of charge carriers and tunable electronic properties.
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Affiliation(s)
- Michelle A Smeaton
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Ismail El Baggari
- Department of Physics, Cornell University, Ithaca, New York 14853, United States
| | - Daniel M Balazs
- Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Tobias Hanrath
- Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Lena F Kourkoutis
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, United States
- Kavli Institute for Nanoscale Science, Cornell University, Ithaca, New York 14853, United States
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30
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Maier A, Löffler R, Scheele M. Fabrication of nanocrystal superlattice microchannels by soft-lithography for electronic measurements of single-crystalline domains. NANOTECHNOLOGY 2020; 31:405302. [PMID: 32531775 DOI: 10.1088/1361-6528/ab9c52] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We report a high-throughput and easy-to-implement approach to fabricate microchannels of nanocrystal superlattices with dimensions of ∼4 μm2, thus approaching the size of typical single-crystalline domains. By means of microcontact printing, highly ordered superlattices with microscale dimensions are transferred onto photolithographically prepatterned microelectrodes, obtaining well-defined superlattice microchannels. We present step-by-step guidelines for microfabrication, nanocrystal self-assembly and patterning to archive large quantities of up to 330 microchannels per device for statistically meaningful investigations of charge transport in single-crystalline superlattice domains. As proof-of-concept, we perform conductivity and field-effect transistor measurements on microchannels of PbS nanocrystal superlattices. We find that the electric transport within microchannel superlattices is orders of magnitude more efficient than within conventional large-scale channels, highlighting the advantage of the near single-crystalline microchannels presented in this paper.
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Affiliation(s)
- Andre Maier
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, D-72076, Tübingen, Germany. Center for Light-Matter Interaction, Sensors & Analytics LISA+, University of Tübingen, Auf der Morgenstelle 15, D-72076, Tübingen, Germany
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31
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Chen IY, Cimada daSilva J, Balazs DM, Smeaton MA, Kourkoutis LF, Hanrath T, Clancy P. The Role of Dimer Formation in the Nucleation of Superlattice Transformations and Its Impact on Disorder. ACS NANO 2020; 14:11431-11441. [PMID: 32804472 DOI: 10.1021/acsnano.0c03800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The formation of defect-free two-dimensional nanocrystal (NC) superstructures remains a challenge as persistent defects hinder charge delocalization and related device performance. Understanding defect formation is an important step toward developing strategies to mitigate their formation. However, specific mechanisms of defect formation are difficult to determine, as superlattice phase transformations that occur during fabrication are quite complex and there are a variety of factors influencing the disorder in the final structure. Here, we use Molecular Dynamics (MD) and electron microscopy in concert to investigate the nucleation of the epitaxial attachment of lead chalcogenide (PbX, where X = S, Se) NC assemblies. We use an updated implementation of an existing reactive force field in an MD framework to investigate how initial orientational (mis)alignment of the constituent building blocks impacts the final structure of the epitaxially connected superlattice. This Simple Molecular Reactive Force Field (SMRFF) captures both short-range covalent forces and long-range electrostatic forces and allows us to follow orientational and translational changes of NCs during superlattice transformation. Our simulations reveal how robust the oriented attachment is with regard to the initial configuration of the NCs, measuring its sensitivity to both in-plane and out-of-plane misorientation. We show that oriented attachment nucleates through the initial formation of dimers, which corroborate experimentally observed structures. We present high-resolution structural analysis of dimers at early stages of the superlattice transformation and rationalize their contribution to the formation of defects in the final superlattice. Collectively, the simulations and experiments presented in this paper provide insights into the nucleation of NC oriented attachment, the impact of the initial configuration of NCs on the structural fidelity of the final epitaxially connected superlattice, and the propensity to form commonly observed defects, such as missing bridges and atomic misalignment in the superlattice due to the formation of dimers. We present potential strategies to mitigate the formation of superlattice defects.
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Affiliation(s)
- Isaiah Y Chen
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | | | | | | | | | | | - Paulette Clancy
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
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32
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Maier A, Lapkin D, Mukharamova N, Frech P, Assalauova D, Ignatenko A, Khubbutdinov R, Lazarev S, Sprung M, Laible F, Löffler R, Previdi N, Bräuer A, Günkel T, Fleischer M, Schreiber F, Vartanyants IA, Scheele M. Structure-Transport Correlation Reveals Anisotropic Charge Transport in Coupled PbS Nanocrystal Superlattices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2002254. [PMID: 32725688 DOI: 10.1002/adma.202002254] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 06/17/2020] [Indexed: 06/11/2023]
Abstract
The assembly of colloidal semiconductive nanocrystals into highly ordered superlattices predicts novel structure-related properties by design. However, those structure-property relationships, such as charge transport depending on the structure or even directions of the superlattice, have remained unrevealed so far. Here, electric transport measurements and X-ray nanodiffraction are performed on self-assembled lead sulfide nanocrystal superlattices to investigate direction-dependent charge carrier transport in microscopic domains of these materials. By angular X-ray cross-correlation analysis, the structure and orientation of individual superlattices is determined, which are directly correlated with the electronic properties of the same microdomains. By that, strong evidence for the effect of superlattice crystallinity on the electric conductivity is found. Further, anisotropic charge transport in highly ordered monocrystalline domains is revealed, which is attributed to the dominant effect of shortest interparticle distance. This implies that transport anisotropy should be a general feature of weakly coupled nanocrystal superlattices.
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Affiliation(s)
- Andre Maier
- Institute of Physical and Theoretical Chemistry, University of Tuebingen, Auf der Morgenstelle 18, Tuebingen, 72076, Germany
- Center for Light-Matter Interaction, Sensors & Analytics LISA+, University of Tuebingen, Auf der Morgenstelle 15, Tuebingen, 72076, Germany
| | - Dmitry Lapkin
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, Hamburg, 22607, Germany
| | | | - Philipp Frech
- Institute of Physical and Theoretical Chemistry, University of Tuebingen, Auf der Morgenstelle 18, Tuebingen, 72076, Germany
| | - Dameli Assalauova
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, Hamburg, 22607, Germany
| | - Alexandr Ignatenko
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, Hamburg, 22607, Germany
| | - Ruslan Khubbutdinov
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, Hamburg, 22607, Germany
- National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Kashirskoe shosse 31, Moscow, 115409, Russia
| | - Sergey Lazarev
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, Hamburg, 22607, Germany
- National Research Tomsk Polytechnic University (TPU), pr. Lenina 30, Tomsk, 634050, Russia
| | - Michael Sprung
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, Hamburg, 22607, Germany
| | - Florian Laible
- Center for Light-Matter Interaction, Sensors & Analytics LISA+, University of Tuebingen, Auf der Morgenstelle 15, Tuebingen, 72076, Germany
- Institute of Applied Physics, University of Tuebingen, Auf der Morgenstelle 10, Tuebingen, 72076, Germany
| | - Ronny Löffler
- Center for Light-Matter Interaction, Sensors & Analytics LISA+, University of Tuebingen, Auf der Morgenstelle 15, Tuebingen, 72076, Germany
| | - Nicolas Previdi
- Institute of Physical and Theoretical Chemistry, University of Tuebingen, Auf der Morgenstelle 18, Tuebingen, 72076, Germany
| | - Annika Bräuer
- Center for Light-Matter Interaction, Sensors & Analytics LISA+, University of Tuebingen, Auf der Morgenstelle 15, Tuebingen, 72076, Germany
- Institute of Applied Physics, University of Tuebingen, Auf der Morgenstelle 10, Tuebingen, 72076, Germany
| | - Thomas Günkel
- Institute of Applied Physics, University of Tuebingen, Auf der Morgenstelle 10, Tuebingen, 72076, Germany
| | - Monika Fleischer
- Center for Light-Matter Interaction, Sensors & Analytics LISA+, University of Tuebingen, Auf der Morgenstelle 15, Tuebingen, 72076, Germany
- Institute of Applied Physics, University of Tuebingen, Auf der Morgenstelle 10, Tuebingen, 72076, Germany
| | - Frank Schreiber
- Center for Light-Matter Interaction, Sensors & Analytics LISA+, University of Tuebingen, Auf der Morgenstelle 15, Tuebingen, 72076, Germany
- Institute of Applied Physics, University of Tuebingen, Auf der Morgenstelle 10, Tuebingen, 72076, Germany
| | - Ivan A Vartanyants
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, Hamburg, 22607, Germany
- National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Kashirskoe shosse 31, Moscow, 115409, Russia
| | - Marcus Scheele
- Institute of Physical and Theoretical Chemistry, University of Tuebingen, Auf der Morgenstelle 18, Tuebingen, 72076, Germany
- Center for Light-Matter Interaction, Sensors & Analytics LISA+, University of Tuebingen, Auf der Morgenstelle 15, Tuebingen, 72076, Germany
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33
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Zheng W, Bonn M, Wang HI. Photoconductivity Multiplication in Semiconducting Few-Layer MoTe 2. NANO LETTERS 2020; 20:5807-5813. [PMID: 32697101 PMCID: PMC7458477 DOI: 10.1021/acs.nanolett.0c01693] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 07/22/2020] [Indexed: 06/11/2023]
Abstract
We report efficient photoconductivity multiplication in few-layer 2H-MoTe2 as a direct consequence of an efficient steplike carrier multiplication with near unity quantum yield and high carrier mobility (∼45 cm2 V-1 s-1) in MoTe2. This photoconductivity multiplication is quantified using ultrafast, excitation-wavelength-dependent photoconductivity measurements employing contact-free terahertz spectroscopy. We discuss the possible origins of efficient carrier multiplication in MoTe2 to guide future theoretical investigations. The combination of photoconductivity multiplication and the advantageous bandgap renders MoTe2 as a promising candidate for efficient optoelectronic devices.
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Affiliation(s)
- Wenhao Zheng
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Mischa Bonn
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Hai I. Wang
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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34
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Deng K, Luo Z, Tan L, Quan Z. Self-assembly of anisotropic nanoparticles into functional superstructures. Chem Soc Rev 2020; 49:6002-6038. [PMID: 32692337 DOI: 10.1039/d0cs00541j] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Self-assembly of colloidal nanoparticles (NPs) into superstructures offers a flexible and promising pathway to manipulate the nanometer-sized particles and thus make full use of their unique properties. This bottom-up strategy builds a bridge between the NP regime and a new class of transformative materials across multiple length scales for technological applications. In this field, anisotropic NPs with size- and shape-dependent physical properties as self-assembly building blocks have long fascinated scientists. Self-assembly of anisotropic NPs not only opens up exciting opportunities to engineer a variety of intriguing and complex superlattice architectures, but also provides access to discover emergent collective properties that stem from their ordered arrangement. Thus, this has stimulated enormous research interests in both fundamental science and technological applications. This present review comprehensively summarizes the latest advances in this area, and highlights their rich packing behaviors from the viewpoint of NP shape. We provide the basics of the experimental techniques to produce NP superstructures and structural characterization tools, and detail the delicate assembled structures. Then the current understanding of the assembly dynamics is discussed with the assistance of in situ studies, followed by emergent collective properties from these NP assemblies. Finally, we end this article with the remaining challenges and outlook, hoping to encourage further research in this field.
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Affiliation(s)
- Kerong Deng
- Department of Chemistry, Academy for Advanced Interdisciplinary Studies, Key Laboratory of Energy Conversion and Storage Technologies, Ministry of Education, Southern University of Science and Technology (SUSTech), Shenzhen, Guangdong 518055, China.
| | - Zhishan Luo
- Department of Chemistry, Academy for Advanced Interdisciplinary Studies, Key Laboratory of Energy Conversion and Storage Technologies, Ministry of Education, Southern University of Science and Technology (SUSTech), Shenzhen, Guangdong 518055, China.
| | - Li Tan
- Department of Chemistry, Academy for Advanced Interdisciplinary Studies, Key Laboratory of Energy Conversion and Storage Technologies, Ministry of Education, Southern University of Science and Technology (SUSTech), Shenzhen, Guangdong 518055, China.
| | - Zewei Quan
- Department of Chemistry, Academy for Advanced Interdisciplinary Studies, Key Laboratory of Energy Conversion and Storage Technologies, Ministry of Education, Southern University of Science and Technology (SUSTech), Shenzhen, Guangdong 518055, China.
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35
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daSilva JC, Smeaton MA, Dunbar TA, Xu Y, Balazs DM, Kourkoutis LF, Hanrath T. Mechanistic Insights into Superlattice Transformation at a Single Nanocrystal Level Using Nanobeam Electron Diffraction. NANO LETTERS 2020; 20:5267-5274. [PMID: 32484679 DOI: 10.1021/acs.nanolett.0c01579] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Understanding the mechanism and ultimately directing nanocrystal (NC) superlattice assembly and attachment have important implications on future advances in this emerging field. Here, we use 4D-STEM to investigate a monolayer of PbS NCs at various stages of the transformation from a hexatic assembly to a nonconnected square-like superlattice over large fields of view. Maps of nanobeam electron diffraction patterns acquired with an electron microscope pixel array detector (EMPAD) offer unprecedented detail into the 3D crystallographic alignment of the polyhedral NCs. Our analysis reveals that superlattice transformation is dominated by translation of prealigned NCs strongly coupled along the <11n>AL direction and occurs stochastically and gradually throughout single grains. We validate the generality of the proposed mechanism by examining the structure of analogous PbSe NC assemblies using conventional transmission electron microscopy and selected area electron diffraction. The experimental results presented here provide new mechanistic insights into NC self-assembly and oriented attachment.
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36
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Unravelling three-dimensional adsorption geometries of PbSe nanocrystal monolayers at a liquid-air interface. Commun Chem 2020; 3:28. [PMID: 36703462 PMCID: PMC9814399 DOI: 10.1038/s42004-020-0275-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 01/07/2020] [Indexed: 01/29/2023] Open
Abstract
The adsorption, self-organization and oriented attachment of PbSe nanocrystals (NCs) at liquid-air interfaces has led to remarkable nanocrystal superlattices with atomic order and a superimposed nanoscale geometry. Earlier studies examined the NC self-organization at the suspension/air interface with time-resolved in-situ X-ray scattering. Upon continuous evaporation of the solvent, the NC interfacial layer will finally contact the (ethylene glycol) liquid substrate on which the suspension was casted. In order to obtain structural information on the NC organization at this stage of the process, we examined the ethylene glycol/NC interface in detail for PbSe NCs of different sizes, combining in-situ grazing-incidence small-and-wide-angle X-ray scattering (GISAXS/GIWAXS), X-ray reflectivity (XRR) and analytical calculations of the adsorption geometry of these NCs. Here, we observe in-situ three characteristic adsorption geometries varying with the NC size. Based on the experimental evidence and simulations, we reveal fully three-dimensional arrangements of PbSe nanocrystals at the ethylene glycol-air interface with and without the presence of rest amounts of toluene.
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37
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Abelson A, Qian C, Salk T, Luan Z, Fu K, Zheng JG, Wardini JL, Law M. Collective topo-epitaxy in the self-assembly of a 3D quantum dot superlattice. NATURE MATERIALS 2020; 19:49-55. [PMID: 31611669 DOI: 10.1038/s41563-019-0485-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Accepted: 08/15/2019] [Indexed: 05/25/2023]
Abstract
Epitaxially fused colloidal quantum dot (QD) superlattices (epi-SLs) may enable a new class of semiconductors that combine the size-tunable photophysics of QDs with bulk-like electronic performance, but progress is hindered by a poor understanding of epi-SL formation and surface chemistry. Here we use X-ray scattering and correlative electron imaging and diffraction of individual SL grains to determine the formation mechanism of three-dimensional PbSe QD epi-SL films. We show that the epi-SL forms from a rhombohedrally distorted body centred cubic parent SL via a phase transition in which the QDs translate with minimal rotation (~10°) and epitaxially fuse across their {100} facets in three dimensions. This collective epitaxial transformation is atomically topotactic across the 103-105 QDs in each SL grain. Infilling the epi-SLs with alumina by atomic layer deposition greatly changes their electrical properties without affecting the superlattice structure. Our work establishes the formation mechanism of three-dimensional QD epi-SLs and illustrates the critical importance of surface chemistry to charge transport in these materials.
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Affiliation(s)
- Alex Abelson
- Department of Materials Science and Engineering, University of California, Irvine, Irvine, CA, USA
| | - Caroline Qian
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, Irvine, CA, USA
| | - Trenton Salk
- Department of Physics and Astronomy, University of California, Irvine, Irvine, CA, USA
| | - Zhongyue Luan
- Department of Materials Science and Engineering, University of California, Irvine, Irvine, CA, USA
| | - Kan Fu
- Department of Materials Science and Engineering, University of California, Irvine, Irvine, CA, USA
| | - Jian-Guo Zheng
- Irvine Materials Research Institute, University of California, Irvine, Irvine, CA, USA
| | - Jenna L Wardini
- Department of Materials Science and Engineering, University of California, Irvine, Irvine, CA, USA
| | - Matt Law
- Department of Materials Science and Engineering, University of California, Irvine, Irvine, CA, USA.
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, Irvine, CA, USA.
- Department of Chemistry, University of California, Irvine, Irvine, CA, USA.
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38
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Walravens W, Solano E, Geenen F, Dendooven J, Gorobtsov O, Tadjine A, Mahmoud N, Ding PP, Ruff JPC, Singer A, Roelkens G, Delerue C, Detavernier C, Hens Z. Setting Carriers Free: Healing Faulty Interfaces Promotes Delocalization and Transport in Nanocrystal Solids. ACS NANO 2019; 13:12774-12786. [PMID: 31693334 DOI: 10.1021/acsnano.9b04757] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Superlattices of epitaxially connected nanocrystals (NCs) are model systems to study electronic and optical properties of NC arrays. Using elemental analysis and structural analysis by in situ X-ray fluorescence and grazing-incidence small-angle scattering, respectively, we show that epitaxial superlattices of PbSe NCs keep their structural integrity up to temperatures of 300 °C; an ideal starting point to assess the effect of gentle thermal annealing on the superlattice properties. We find that annealing such superlattices between 75 and 150 °C induces a marked red shift of the NC band-edge transition. In fact, the post-annealing band-edge reflects theoretical predictions on the impact of charge carrier delocalization in these epitaxial superlattices. In addition, we observe a pronounced enhancement of the charge carrier mobility and a reduction of the hopping activation energy after mild annealing. While the superstructure remains intact at these temperatures, structural defect studies through X-ray diffraction indicate that annealing markedly decreases the density of point defects and edge dislocations. This indicates that the connections between NCs in as-synthesized superlattices still form a major source of grain boundaries and defects, which prevent carrier delocalization over multiple NCs and hamper NC-to-NC transport. Overcoming the limitations imposed by interfacial defects is therefore an essential next step in the development of high-quality optoelectronic devices based on NC solids.
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Affiliation(s)
- Willem Walravens
- Physics and Chemistry of Nanostructures (PCN) , Ghent University , 9000 Gent , Belgium
- Center for Nano and Biophotonics , Ghent University , 9000 Gent , Belgium
| | - Eduardo Solano
- NCD-SWEET beamline, ALBA Synchrotron Light Source , Carrer de la Llum 2-26 , 08290 Cerdanyola del Vallès , Spain
| | - Filip Geenen
- Center for Nano and Biophotonics , Ghent University , 9000 Gent , Belgium
- Department of Solid State Sciences, CoCooN group , Ghent University , 9000 Gent , Belgium
| | - Jolien Dendooven
- Center for Nano and Biophotonics , Ghent University , 9000 Gent , Belgium
- Department of Solid State Sciences, CoCooN group , Ghent University , 9000 Gent , Belgium
| | - Oleg Gorobtsov
- Department of Materials Science and Engineering , Cornell University , Ithaca , New York 14850 , United States
| | - Athmane Tadjine
- Université de Lille , CNRS, Centrale Lille, Yncrea-ISEN, UPHF, UMR 8520-IEMN, 59000 Lille , France
| | - Nayyera Mahmoud
- Center for Nano and Biophotonics , Ghent University , 9000 Gent , Belgium
- Photonics Research Group , Ghent University , 9000 Gent , Belgium
| | - Patrick Peiwen Ding
- Department of Materials Science and Engineering , Cornell University , Ithaca , New York 14850 , United States
| | - Jacob P C Ruff
- CHESS , Cornell University , Ithaca , New York 14850 , United States
| | - Andrej Singer
- Department of Materials Science and Engineering , Cornell University , Ithaca , New York 14850 , United States
| | - Gunther Roelkens
- Center for Nano and Biophotonics , Ghent University , 9000 Gent , Belgium
- Photonics Research Group , Ghent University , 9000 Gent , Belgium
| | - Christophe Delerue
- Université de Lille , CNRS, Centrale Lille, Yncrea-ISEN, UPHF, UMR 8520-IEMN, 59000 Lille , France
| | - Christophe Detavernier
- Center for Nano and Biophotonics , Ghent University , 9000 Gent , Belgium
- Department of Solid State Sciences, CoCooN group , Ghent University , 9000 Gent , Belgium
| | - Zeger Hens
- Physics and Chemistry of Nanostructures (PCN) , Ghent University , 9000 Gent , Belgium
- Center for Nano and Biophotonics , Ghent University , 9000 Gent , Belgium
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39
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Ondry JC, Philbin JP, Lostica M, Rabani E, Alivisatos AP. Resilient Pathways to Atomic Attachment of Quantum Dot Dimers and Artificial Solids from Faceted CdSe Quantum Dot Building Blocks. ACS NANO 2019; 13:12322-12344. [PMID: 31246407 DOI: 10.1021/acsnano.9b03052] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The goal of this work is to identify favored pathways for preparation of defect-resilient attached wurtzite CdX (X = S, Se, Te) nanocrystals. We seek guidelines for oriented attachment of faceted nanocrystals that are most likely to yield pairs of nanocrystals with either few or no electronic defects or electronic defects that are in and of themselves desirable and stable. Using a combination of in situ high-resolution transmission electron microscopy (HRTEM) and electronic structure calculations, we evaluate the relative merits of atomic attachment of wurtzite CdSe nanocrystals on the {11̅00} or {112̅0} family of facets. Pairwise attachment on either facet can lead to perfect interfaces, provided the nanocrystal facets are perfectly flat and the angles between the nanocrystals can adjust during the assembly. Considering defective attachment, we observe for {11̅00} facet attachment that only one type of edge dislocation forms, creating deep hole traps. For {112̅0} facet attachment, we observe that four distinct types of extended defects form, some of which lead to deep hole traps whereas others only to shallow hole traps. HRTEM movies of the dislocation dynamics show that dislocations at {11̅00} interfaces can be removed, albeit slowly. Whereas only some extended defects at {112̅0} interfaces could be removed, others were trapped at the interface. Based on these insights, we identify the most resilient pathways to atomic attachment of pairs of wurtzite CdX nanocrystals and consider how these insights can translate to the creation of electronically useful materials from quantum dots with other crystal structures.
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Affiliation(s)
- Justin C Ondry
- Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - John P Philbin
- Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Michael Lostica
- Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Eran Rabani
- Department of Chemistry , University of California , Berkeley , California 94720 , United States
- Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
- The Sackler Center for Computational Molecular and Materials Science , Tel Aviv University , Tel Aviv 69978 , Israel
| | - A Paul Alivisatos
- Department of Chemistry , University of California , Berkeley , California 94720 , United States
- Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
- Department of Materials Science and Engineering , University of California , Berkeley , California 94720 , United States
- Kavli Energy NanoScience Institute , Berkeley , California 94720 , United States
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40
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Liu L, Bisri SZ, Ishida Y, Aida T, Iwasa Y. Tunable electronic properties by ligand coverage control in PbS nanocrystal assemblies. NANOSCALE 2019; 11:20467-20474. [PMID: 31647086 DOI: 10.1039/c9nr07101f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
It is well-known that controlling electronic properties of nanocrystal (NC) assemblies can be achieved by the usage of various types of ligands on the NC surface. However, the ligand coverage, which could also tune electronic properties, is always ignored. It is due to the lack of accurate evaluation methods of ligand amounts on the surface of NCs and the difficulty of ligand binding control at the nanoscale. Here, we demonstrate a precise ligand (oleic acid) coverage control of PbS NCs through a modified liquid/air assembly technique. In this way, both the assembly structures and electronic properties can be tuned by ligand coverage at the same time. In particular, the medium oleic acid coverage (2.1 ligand per nm2), which forms a square lattice of PbS NCs, shows the best electronic properties, especially when it is compared with the full coverage (2.4 ligand per nm2) and the sparse coverage (0.7 ligand per nm2) of oleic acid on the NC surface. This ligand coverage controlled electronic properties of NC films will give new insights for finely tuning the properties of electronic devices based on NCs.
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Affiliation(s)
- Liming Liu
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | | | - Yasuhiro Ishida
- RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
| | - Takuzo Aida
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan and RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
| | - Yoshihiro Iwasa
- RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. and Quantum-Phase Electronics Center and Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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41
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McCray ARC, Savitzky BH, Whitham K, Hanrath T, Kourkoutis LF. Orientational Disorder in Epitaxially Connected Quantum Dot Solids. ACS NANO 2019; 13:11460-11468. [PMID: 31502825 DOI: 10.1021/acsnano.9b04951] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Periodic arrays of strongly coupled colloidal quantum dots (QDs) may enable unprecedented control of electronic band structure through manipulation of QD size, shape, composition, spacing, and assembly geometry. This includes the possibilities of precisely engineered bandgaps and charge carrier mobilities, as well as remarkable behaviors such as metal-insulator transitions, massless carriers, and topological states. However, experimental realization of these theoretically predicted electronic structures is presently limited by structural disorder. Here, we use aberration-corrected scanning transmission electron microscopy to precisely quantify the orientational disorder of epitaxially connected QD films. In spite of coherent atomic connectivity between nearest neighbor QDs, we find misalignment persists with a standard deviation of 1.9°, resulting in significant bending strain localized to the adjoining necks. We observe and quantify a range of out-of-plane particle orientations over thousands of QDs and correlate the in-plane and out-of-plane misalignments, finding QDs misoriented out-of-plane display a statistically greater misalignment with respect to their in-plane neighbors as well. Using the bond orientational order metric ψ4, we characterize the 4-fold symmetry and introduce a quantification of the local superlattice (SL) orientation. This enables direct comparison between local orientational order in the SL and atomic lattice (AL). We find significantly larger variations in the SL orientation and a statistically robust but locally highly variable correlation between the orientations of the two differently scaled lattices. Distinct AL and SL behaviors are observed about a grain boundary, with a sharp boundary in the AL orientations, but a more smooth transition in the SL, facilitated by lattice deformation between the neighboring grains. Coupling between the AL and SL is a fundamental driver of film growth, and these results suggest nontrivial underlying mechanics, implying that simplified models of epitaxial attachment may be insufficient to understand QD growth and disorder when oriented attachment and superlattice growth occur in concert.
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Affiliation(s)
- Arthur R C McCray
- School of Applied and Engineering Physics , Cornell University , Ithaca , New York 14853 , United States
| | - Benjamin H Savitzky
- Department of Physics , Cornell University , Ithaca , New York 14853 , United States
| | - Kevin Whitham
- Department of Materials Science and Engineering , Cornell University , Ithaca , New York 14853 , United States
| | - Tobias Hanrath
- School of Chemical and Biomolecular Engineering , Cornell University , Ithaca , New York 14853 , United States
| | - Lena F Kourkoutis
- School of Applied and Engineering Physics , Cornell University , Ithaca , New York 14853 , United States
- Kavli Institute for Nanoscale Science , Cornell University , Ithaca , New York 14853 , United States
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42
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Liu Y, Peard N, Grossman JC. Bandlike Transport in PbS Quantum Dot Superlattices with Quantum Confinement. J Phys Chem Lett 2019; 10:3756-3762. [PMID: 31185712 DOI: 10.1021/acs.jpclett.9b01282] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Optoelectronic devices made from colloidal quantum dots (CQDs) often take advantage of the combination of tunable quantum-confined optical properties and carrier mobilities of strongly coupled systems. In this work, first-principles calculations are applied to investigate the electronic, optical, and transport properties of PbS CQD superlattices. Our results show that even in the regime of strong necking and fusing between PbS CQDs, quantum confinement can be generally preserved. In particular, computed carrier mobilities for simple cubic and two-dimensional square lattices fused along the {100} facets are 2-3 orders of magnitude larger than those of superlattices fused along {110} and {111} facets. The relative magnitude of the electron and hole mobilities strongly depends on the crystal and electronic structures. Our results illustrate the importance of understanding the crystal structure of CQD films and that strongly fused CQD superlattices offer a promising pathway for achieving tunable quantum-confined optical properties while increasing carrier mobilities.
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Affiliation(s)
- Yun Liu
- Department of Materials Science and Engineering , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Nolan Peard
- Department of Physics , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Jeffrey C Grossman
- Department of Materials Science and Engineering , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
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43
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Alimoradi Jazi M, Kulkarni A, Sinai SB, Peters JL, Geschiere E, Failla M, Delerue C, Houtepen AJ, Siebbeles LDA, Vanmaekelbergh D. Room-Temperature Electron Transport in Self-Assembled Sheets of PbSe Nanocrystals with a Honeycomb Nanogeometry. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2019; 123:14058-14066. [PMID: 31205579 PMCID: PMC6559210 DOI: 10.1021/acs.jpcc.9b03549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Indexed: 06/09/2023]
Abstract
It has been shown recently that atomically coherent superstructures of a nanocrystal monolayer in thickness can be prepared by self-assembly of monodisperse PbSe nanocrystals, followed by oriented attachment. Superstructures with a honeycomb nanogeometry are of special interest, as theory has shown that they are regular 2-D semiconductors, but with the highest valence and lowest conduction bands being Dirac-type, that is, with a linear energy-momentum relation around the K-points in the zone. Experimental validation will require cryogenic measurements on single sheets of these nanocrystal monolayer superstructures. Here, we show that we can incorporate these fragile superstructures into a transistor device with electrolyte gating, control the electron density, and measure the electron transport characteristics at room temperature. The electron mobility is 1.5 ± 0.5 cm2 V-1 s-1, similar to the mobility observed with terahertz spectroscopy on freestanding superstructures. The terahertz spectroscopic data point to pronounced carrier scattering on crystallographic imperfections in the superstructure, explaining the limited mobility.
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Affiliation(s)
- Maryam Alimoradi Jazi
- Debye Institute
for Nanomaterials Science, University of
Utrecht, Princetonplein 1, 3584 CC, Utrecht, The Netherlands
| | - Aditya Kulkarni
- Optoelectronic Materials Section, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Sophia Buhbut Sinai
- Debye Institute
for Nanomaterials Science, University of
Utrecht, Princetonplein 1, 3584 CC, Utrecht, The Netherlands
| | - Joep L. Peters
- Debye Institute
for Nanomaterials Science, University of
Utrecht, Princetonplein 1, 3584 CC, Utrecht, The Netherlands
| | - Eva Geschiere
- Optoelectronic Materials Section, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Michele Failla
- Optoelectronic Materials Section, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | | | - Arjan J. Houtepen
- Optoelectronic Materials Section, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Laurens D. A. Siebbeles
- Optoelectronic Materials Section, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Daniel Vanmaekelbergh
- Debye Institute
for Nanomaterials Science, University of
Utrecht, Princetonplein 1, 3584 CC, Utrecht, The Netherlands
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44
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Wang Y, Peng X, Abelson A, Xiao P, Qian C, Yu L, Ophus C, Ercius P, Wang LW, Law M, Zheng H. Dynamic deformability of individual PbSe nanocrystals during superlattice phase transitions. SCIENCE ADVANCES 2019; 5:eaaw5623. [PMID: 31187062 PMCID: PMC6555630 DOI: 10.1126/sciadv.aaw5623] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 04/26/2019] [Indexed: 05/12/2023]
Abstract
The behavior of individual nanocrystals during superlattice phase transitions can profoundly affect the structural perfection and electronic properties of the resulting superlattices. However, details of nanocrystal morphological changes during superlattice phase transitions are largely unknown due to the lack of direct observation. Here, we report the dynamic deformability of PbSe semiconductor nanocrystals during superlattice phase transitions that are driven by ligand displacement. Real-time high-resolution imaging with liquid-phase transmission electron microscopy reveals that following ligand removal, the individual PbSe nanocrystals experience drastic directional shape deformation when the spacing between nanocrystals reaches 2 to 4 nm. The deformation can be completely recovered when two nanocrystals move apart or it can be retained when they attach. The large deformation, which is responsible for the structural defects in the epitaxially fused nanocrystal superlattice, may arise from internanocrystal dipole-dipole interactions.
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Affiliation(s)
- Yu Wang
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Xinxing Peng
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- State Key Lab of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China
| | - Alex Abelson
- Department of Chemistry, University of California, Irvine, Irvine, CA, 92697, USA
| | - Penghao Xiao
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Caroline Qian
- Department of Chemistry, University of California, Irvine, Irvine, CA, 92697, USA
| | - Lei Yu
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Colin Ophus
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Peter Ercius
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Lin-Wang Wang
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Matt Law
- Department of Chemistry, University of California, Irvine, Irvine, CA, 92697, USA
| | - Haimei Zheng
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
- Corresponding author.
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45
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Bederak D, Balazs DM, Sukharevska NV, Shulga AG, Abdu-Aguye M, Dirin DN, Kovalenko MV, Loi MA. Comparing Halide Ligands in PbS Colloidal Quantum Dots for Field-Effect Transistors and Solar Cells. ACS APPLIED NANO MATERIALS 2018; 1:6882-6889. [PMID: 30613830 PMCID: PMC6317010 DOI: 10.1021/acsanm.8b01696] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 11/09/2018] [Indexed: 05/05/2023]
Abstract
Capping colloidal quantum dots (CQDs) with atomic ligands is a powerful approach to tune their properties and improve the charge carrier transport in CQD solids. Efficient passivation of the CQD surface, which can be achieved with halide ligands, is crucial for application in optoelectronic devices. Heavier halides, i.e., I- and Br-, have been thoroughly studied as capping ligands in the last years, but passivation with fluoride ions has not received sufficient consideration. In this work, effective coating of PbS CQDs with fluoride ligands is demonstrated and compared to the results obtained with other halides. The electron mobility in field-effect transistors of PbS CQDs treated with different halides shows an increase with the size of the atomic ligand (from 3.9 × 10-4 cm2/(V s) for fluoride-treated to 2.1 × 10-2 cm2/(V s) for iodide-treated), whereas the hole mobility remains unchanged in the range between 1 × 10-5 cm2/(V s) and 10-4cm2/(V s). This leads to a relatively more pronounced p-type behavior of the fluoride- and chloride-treated films compared to the iodide-treated ones. Cl-- and F--capped PbS CQDs solids were then implemented as p-type layer in solar cells; these devices showed similar performance to those prepared with 1,2-ethanedithiol in the same function. The relatively stronger p-type character of the fluoride- and chloride-treated PbS CQD films broadens the utility of such materials in optoelectronic devices.
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Affiliation(s)
- Dmytro Bederak
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Daniel M. Balazs
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Nataliia V. Sukharevska
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Artem G. Shulga
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Mustapha Abdu-Aguye
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Dmitry N. Dirin
- Department
of Chemistry and Applied Biosciences, ETH
Zürich, Vladimir Prelog Weg 1, Zürich 8093, Switzerland
- Empa-Swiss
Federal Laboratories for Materials Science and Technology, Uberlandstrasse 129, Dübendorf 8600, Switzerland
| | - Maksym V. Kovalenko
- Department
of Chemistry and Applied Biosciences, ETH
Zürich, Vladimir Prelog Weg 1, Zürich 8093, Switzerland
- Empa-Swiss
Federal Laboratories for Materials Science and Technology, Uberlandstrasse 129, Dübendorf 8600, Switzerland
| | - Maria A. Loi
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
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46
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Abstract
From a niche field over 30 years ago, quantum dots (QDs) have developed into viable materials for many commercial optoelectronic devices. We discuss the advancements in Pb-based QD solar cells (QDSCs) from a viewpoint of the pathways an excited state can take when relaxing back to the ground state. Systematically understanding the fundamental processes occurring in QDs has led to improvements in solar cell efficiency from ~3% to over 13% in 8 years. We compile data from ~200 articles reporting functioning QDSCs to give an overview of the current limitations in the technology. We find that the open circuit voltage limits the device efficiency and propose some strategies for overcoming this limitation.
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47
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Balazs DM, Matysiak BM, Momand J, Shulga AG, Ibáñez M, Kovalenko MV, Kooi BJ, Loi MA. Electron Mobility of 24 cm 2 V -1 s -1 in PbSe Colloidal-Quantum-Dot Superlattices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1802265. [PMID: 30069938 DOI: 10.1002/adma.201802265] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 06/07/2018] [Indexed: 05/28/2023]
Abstract
Colloidal quantum dots (CQDs) are nanoscale building blocks for bottom-up fabrication of semiconducting solids with tailorable properties beyond the possibilities of bulk materials. Achieving ordered, macroscopic crystal-like assemblies has been in the focus of researchers for years, since it would allow exploitation of the quantum-confinement-based electronic properties with tunable dimensionality. Lead-chalcogenide CQDs show especially strong tendencies to self-organize into 2D superlattices with micrometer-scale order, making the array fabrication fairly simple. However, most studies concentrate on the fundamentals of the assembly process, and none have investigated the electronic properties and their dependence on the nanoscale structure induced by different ligands. Here, it is discussed how different chemical treatments on the initial superlattices affect the nanostructure, the optical, and the electronic-transport properties. Transistors with average two-terminal electron mobilities of 13 cm2 V-1 s-1 and contactless mobility of 24 cm2 V-1 s-1 are obtained for small-area superlattice field-effect transistors. Such mobility values are the highest reported for CQD devices wherein the quantum confinement is substantially present and are comparable to those reported for heavy sintering. The considerable mobility with the simultaneous preservation of the optical bandgap displays the vast potential of colloidal QD superlattices for optoelectronic applications.
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Affiliation(s)
- Daniel M Balazs
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG, Groningen, Netherlands
| | - Bartosz M Matysiak
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG, Groningen, Netherlands
| | - Jamo Momand
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG, Groningen, Netherlands
| | - Artem G Shulga
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG, Groningen, Netherlands
| | - Maria Ibáñez
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1, Zürich, 8093, Switzerland
- Empa-Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, Dübendorf, 8600, Switzerland
| | - Maksym V Kovalenko
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1, Zürich, 8093, Switzerland
- Empa-Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, Dübendorf, 8600, Switzerland
| | - Bart J Kooi
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG, Groningen, Netherlands
| | - Maria Antonietta Loi
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG, Groningen, Netherlands
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48
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Gilmore RH, Winslow SW, Lee EMY, Ashner MN, Yager KG, Willard AP, Tisdale WA. Inverse Temperature Dependence of Charge Carrier Hopping in Quantum Dot Solids. ACS NANO 2018; 12:7741-7749. [PMID: 29927579 DOI: 10.1021/acsnano.8b01643] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In semiconductors, increasing mobility with decreasing temperature is a signature of charge carrier transport through delocalized bands. Here, we show that this behavior can also occur in nanocrystal solids due to temperature-dependent structural transformations. Using a combination of broadband infrared transient absorption spectroscopy and numerical modeling, we investigate the temperature-dependent charge transport properties of well-ordered PbS quantum dot (QD) solids. Contrary to expectations, we observe that the QD-to-QD charge tunneling rate increases with decreasing temperature, while simultaneously exhibiting thermally activated nearest-neighbor hopping behavior. Using synchrotron grazing-incidence small-angle X-ray scattering, we show that this trend is driven by a temperature-dependent reduction in nearest-neighbor separation that is quantitatively consistent with the measured tunneling rate.
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Affiliation(s)
| | | | | | | | - Kevin G Yager
- Center for Functional Nanomaterials , Brookhaven National Laboratory , Upton , New York 11973 , United States
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49
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André A, Weber M, Wurst KM, Maiti S, Schreiber F, Scheele M. Electron-Conducting PbS Nanocrystal Superlattices with Long-Range Order Enabled by Terthiophene Molecular Linkers. ACS APPLIED MATERIALS & INTERFACES 2018; 10:24708-24714. [PMID: 29968457 DOI: 10.1021/acsami.8b06044] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
PbS nanocrystals are surface-functionalized with the organic semiconductor 5,5″-dithiol-[2,2':5,2″-terthiophene] and assembled to afford hybrid nanostructured thin films with a large structural coherence and an electron mobility of 0.2 cm2/(V s). Electrochemistry, optical spectroscopy, and quantum mechanical calculations are applied to elucidate the electronic structure at the inorganic/organic interface, and it is established that electron injection into the molecule alters its (electronic) structure, which greatly facilitates coupling of the neighboring PbS 1Se states. This is verified by field-effect and electrochemically gated transport measurements, and evidence is provided that carrier transport occurs predominantly via the 1Se states. The presented material allows studying structure-transport correlations and exploring transport anisotropies in semiconductor nanocrystal superlattices.
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Affiliation(s)
- Alexander André
- Institute for Physical and Theoretical Chemistry , University of Tübingen , Auf der Morgenstelle 18 , 72076 Tübingen , Germany
| | - Michelle Weber
- Institute for Physical and Theoretical Chemistry , University of Tübingen , Auf der Morgenstelle 18 , 72076 Tübingen , Germany
| | - Kai M Wurst
- Institute for Physical and Theoretical Chemistry , University of Tübingen , Auf der Morgenstelle 18 , 72076 Tübingen , Germany
| | - Santanu Maiti
- Institute of Applied Physics , University of Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
| | - Frank Schreiber
- Institute of Applied Physics , University of Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
- Center for Light-Matter Interaction, Sensors & Analytics LISA+ , University of Tübingen , Auf der Morgenstelle 15 , 72076 Tübingen , Germany
| | - Marcus Scheele
- Institute for Physical and Theoretical Chemistry , University of Tübingen , Auf der Morgenstelle 18 , 72076 Tübingen , Germany
- Center for Light-Matter Interaction, Sensors & Analytics LISA+ , University of Tübingen , Auf der Morgenstelle 15 , 72076 Tübingen , Germany
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50
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Gong J, Yang M, Rebollar D, Rucinski J, Liveris Z, Zhu K, Xu T. Divalent Anionic Doping in Perovskite Solar Cells for Enhanced Chemical Stability. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1800973. [PMID: 29984441 DOI: 10.1002/adma.201800973] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 06/05/2018] [Indexed: 06/08/2023]
Abstract
The chemical stabilities of hybrid perovskite materials demand further improvement toward long-term and large-scale photovoltaic applications. Herein, the enhanced chemical stability of CH3 NH3 PbI3 is reported by doping the divalent anion Se2- in the form of PbSe in precursor solutions to enhance the hydrogen-bonding-like interactions between the organic cations and the inorganic framework. As a result, in 100% humidity at 40 °C, the 10% w/w PbSe-doped CH3 NH3 PbI3 films exhibited >140-fold stability improvement over pristine CH3 NH3 PbI3 films. As the PbSe-doped CH3 NH3 PbI3 films maintained the perovskite structure, a top efficiency of 10.4% with 70% retention after 700 h aging in ambient air is achieved with an unencapsulated 10% w/w PbSe:MAPbI3 -based cell. As a bonus, the incorporated Se2- also effectively suppresses iodine diffusion, leading to enhanced chemical stability of the silver electrodes.
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Affiliation(s)
- Jue Gong
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL, 60115, USA
| | - Mengjin Yang
- Chemistry and Nanoscience Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Dominic Rebollar
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL, 60115, USA
| | - Jordan Rucinski
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL, 60115, USA
| | - Zachary Liveris
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL, 60115, USA
| | - Kai Zhu
- Chemistry and Nanoscience Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Tao Xu
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL, 60115, USA
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