1
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Chen HJ, Wang L, Zhu H, Wang ZG, Liu SL. NIR-II Fluorescence Imaging for In Vivo Quantitative Analysis. ACS APPLIED MATERIALS & INTERFACES 2024; 16:28011-28028. [PMID: 38783516 DOI: 10.1021/acsami.4c04913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
In vivo real-time qualitative and quantitative analysis is essential for the diagnosis and treatment of diseases such as tumors. Near-infrared-II (NIR-II, 1000-1700 nm) bioimaging is an emerging visualization modality based on fluorescent materials. The advantages of NIR-II region fluorescent materials in terms of reduced photon scattering and low tissue autofluorescence enable NIR-II bioimaging with high resolution and increasing depth of tissue penetration, and thus have great potential for in vivo qualitative and quantitative analysis. In this review, we first summarize recent advances in NIR-II imaging, including fluorescent probe selection, quantitative analysis strategies, and imaging. Then, we describe in detail representative applications to illustrate how NIR-II fluorescence imaging has become an important tool for in vivo quantitative analysis. Finally, we describe the future possibilities and challenges of NIR-II fluorescence imaging.
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Affiliation(s)
- Hua-Jie Chen
- Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, P. R. China
| | - Lei Wang
- State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Centre for New Organic Matter, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Centre for Analytical Sciences, College of Chemistry and School of Medicine, Nankai University, Tianjin 300071, P. R. China
| | - Han Zhu
- State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Centre for New Organic Matter, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Centre for Analytical Sciences, College of Chemistry and School of Medicine, Nankai University, Tianjin 300071, P. R. China
| | - Zhi-Gang Wang
- State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Centre for New Organic Matter, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Centre for Analytical Sciences, College of Chemistry and School of Medicine, Nankai University, Tianjin 300071, P. R. China
| | - Shu-Lin Liu
- Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, P. R. China
- State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Centre for New Organic Matter, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Centre for Analytical Sciences, College of Chemistry and School of Medicine, Nankai University, Tianjin 300071, P. R. China
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2
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Li Q, Wu K, Zhu H, Yang Y, He S, Lian T. Charge Transfer from Quantum-Confined 0D, 1D, and 2D Nanocrystals. Chem Rev 2024; 124:5695-5763. [PMID: 38629390 PMCID: PMC11082908 DOI: 10.1021/acs.chemrev.3c00742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 03/29/2024] [Accepted: 04/02/2024] [Indexed: 05/09/2024]
Abstract
The properties of colloidal quantum-confined semiconductor nanocrystals (NCs), including zero-dimensional (0D) quantum dots, 1D nanorods, 2D nanoplatelets, and their heterostructures, can be tuned through their size, dimensionality, and material composition. In their photovoltaic and photocatalytic applications, a key step is to generate spatially separated and long-lived electrons and holes by interfacial charge transfer. These charge transfer properties have been extensively studied recently, which is the subject of this Review. The Review starts with a summary of the electronic structure and optical properties of 0D-2D nanocrystals, followed by the advances in wave function engineering, a novel way to control the spatial distribution of electrons and holes, through their size, dimension, and composition. It discusses the dependence of NC charge transfer on various parameters and the development of the Auger-assisted charge transfer model. Recent advances in understanding multiple exciton generation, decay, and dissociation are also discussed, with an emphasis on multiple carrier transfer. Finally, the applications of nanocrystal-based systems for photocatalysis are reviewed, focusing on the photodriven charge separation and recombination processes that dictate the function and performance of these materials. The Review ends with a summary and outlook of key remaining challenges and promising future directions in the field.
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Affiliation(s)
- Qiuyang Li
- Department
of Physics, University of Michigan, 450 Church St, Ann Arbor, Michigan 48109, United States
| | - Kaifeng Wu
- State
Key Laboratory of Molecular Reaction Dynamics and Collaborative Innovation
Center of Chemistry for Energy Materials (iChEM), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China
- University
of Chinese Academy of Sciences, Beijing 100049, China
| | - Haiming Zhu
- Department
of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Ye Yang
- The
State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM
(Collaborative Innovation Center of Chemistry for Energy Materials),
College of Chemistry & Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Sheng He
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Tianquan Lian
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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3
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Zhang P, Wang Y, Su X, Zhang Q, Sun M. Study of Laser-Induced Multi-Exciton Generation and Dynamics by Multi-Photon Absorption in CdSe Quantum Dots. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:558. [PMID: 38607093 PMCID: PMC11013938 DOI: 10.3390/nano14070558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 03/11/2024] [Accepted: 03/18/2024] [Indexed: 04/13/2024]
Abstract
Multi-exciton generation by multi-photon absorption under low-energy photons can be thought a reasonable method to reduce the risk of optical damage, especially in photoelectric quantum dot (QD) devices. The lifetime of the multi-exciton state plays a key role in the utilization of photon-induced carriers, which depends on the dynamics of the exciton generation process in materials. In this paper, the exciton generation dynamics of the photon absorption under low-frequency light in CdSe QDs are successfully detected and studied by the temporal resolution transient absorption (TA) spectroscopy method. Since the cooling time of hot excitons extends while the rate of auger recombination is accelerated when incident energy is increased, the filling time of defect states is irregular, and exciton generation experiences a transition from single-photon absorption to multi-photon absorption. This result shows how to change the excitation. Optical parameters can prolong the lifetime of excitons, thus fully extracting excitons and improving the photoelectric conversion efficiency of QD optoelectronic devices, which provides theoretical and experimental support for the development of QD optoelectronic devices.
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Affiliation(s)
- Peng Zhang
- Institute of Photonic Chips, University of Shanghai for Science and Technology, Shanghai 200093, China; (P.Z.); (Y.W.); (Q.Z.)
- Centre for Artificial-Intelligence Nanophotonics, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Yimeng Wang
- Institute of Photonic Chips, University of Shanghai for Science and Technology, Shanghai 200093, China; (P.Z.); (Y.W.); (Q.Z.)
- Centre for Artificial-Intelligence Nanophotonics, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Xueqiong Su
- School of Physics and Optoelectronic Engineering, Beijing University of Technology, Beijing 100124, China;
| | - Qiwen Zhang
- Institute of Photonic Chips, University of Shanghai for Science and Technology, Shanghai 200093, China; (P.Z.); (Y.W.); (Q.Z.)
- Centre for Artificial-Intelligence Nanophotonics, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Mingyu Sun
- Institute of Photonic Chips, University of Shanghai for Science and Technology, Shanghai 200093, China; (P.Z.); (Y.W.); (Q.Z.)
- Centre for Artificial-Intelligence Nanophotonics, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
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4
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Huang Z, Sun Q, Wang S, Shen H, Cai W, Wang Y. Broadband Tunable Optical Gain from Ecofriendly Semiconductor Quantum Dots with Near-Half-Exciton Threshold. NANO LETTERS 2023; 23:4032-4038. [PMID: 37125767 DOI: 10.1021/acs.nanolett.3c00813] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Optical gain in solution-processable quantum dots (QDs) has attracted intense interest toward next-generation optoelectronics; however, the development of optical gain in heavy-metal-free QDs remains challenging. Herein, we reveal that the ZnSe1-xTex-based QDs show excellent optical gain covering the violet to near-red regime. A new gain mechanism is established in the alloy QDs, which promotes a theoretically threshold-less optical gain thanks to the ultrafast carrier localization and suppression of ground-state absorption by the Te-derived isoelectronic state. Further, we disclose that the hot-carrier trapping represents the main culprit to exacerbate the gain performance. With the increase of Te-to-Se ratio, a sub-band-gap photoinduced absorption (PA) appears and extinguishes the optical gain. To overcome this issue, we modulate the inner ZnSe shell thickness, and the gain is recovered by reducing the overlap between the gain and PA regions in the Te-rich QDs. Our finding represents a significant step toward sustainable QD-based optoelectronics.
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Affiliation(s)
- Zhigao Huang
- MIIT Key Laboratory of Advanced Display Materials and Devices, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Qi Sun
- MIIT Key Laboratory of Advanced Display Materials and Devices, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Sensen Wang
- MIIT Key Laboratory of Advanced Display Materials and Devices, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Hanchen Shen
- MIIT Key Laboratory of Advanced Display Materials and Devices, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Wenbing Cai
- MIIT Key Laboratory of Advanced Display Materials and Devices, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Yue Wang
- MIIT Key Laboratory of Advanced Display Materials and Devices, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
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5
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Kumar K, Wächtler M. Unravelling Dynamics Involving Multiple Charge Carriers in Semiconductor Nanocrystals. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:nano13091579. [PMID: 37177124 PMCID: PMC10181110 DOI: 10.3390/nano13091579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/02/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023]
Abstract
The use of colloidal nanocrystals as part of artificial photosynthetic systems has recently gained significant attention, owing to their strong light absorption and highly reproducible, tunable electronic and optical properties. The complete photocatalytic conversion of water to its components is yet to be achieved in a practically suitable and commercially viable manner. To complete this challenging task, we are required to fully understand the mechanistic aspects of the underlying light-driven processes involving not just single charge carriers but also multiple charge carriers in detail. This review focuses on recent progress in understanding charge carrier dynamics in semiconductor nanocrystals and the influence of various parameters such as dimension, composition, and cocatalysts. Transient absorption spectroscopic studies involving single and multiple charge carriers, and the challenges associated with the need for accumulation of multiple charge carriers to drive the targeted chemical reactions, are discussed.
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Affiliation(s)
- Krishan Kumar
- Department Functional Interfaces, Leibniz Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745 Jena, Germany
| | - Maria Wächtler
- Chemistry Department and State Research Center OPTIMAS, RPTU Kaiserslautern-Landau, Erwin-Schrödinger-Str. 52, 67663 Kaiserslautern, Germany
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6
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Shulenberger KE, Jilek MR, Sherman SJ, Hohman BT, Dukovic G. Electronic Structure and Excited State Dynamics of Cadmium Chalcogenide Nanorods. Chem Rev 2023; 123:3852-3903. [PMID: 36881852 DOI: 10.1021/acs.chemrev.2c00676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
The cylindrical quasi-one-dimensional shape of colloidal semiconductor nanorods (NRs) gives them unique electronic structure and optical properties. In addition to the band gap tunability common to nanocrystals, NRs have polarized light absorption and emission and high molar absorptivities. NR-shaped heterostructures feature control of electron and hole locations as well as light emission energy and efficiency. We comprehensively review the electronic structure and optical properties of Cd-chalcogenide NRs and NR heterostructures (e.g., CdSe/CdS dot-in-rods, CdSe/ZnS rod-in-rods), which have been widely investigated over the last two decades due in part to promising optoelectronic applications. We start by describing methods for synthesizing these colloidal NRs. We then detail the electronic structure of single-component and heterostructure NRs and follow with a discussion of light absorption and emission in these materials. Next, we describe the excited state dynamics of these NRs, including carrier cooling, carrier and exciton migration, radiative and nonradiative recombination, multiexciton generation and dynamics, and processes that involve trapped carriers. Finally, we describe charge transfer from photoexcited NRs and connect the dynamics of these processes with light-driven chemistry. We end with an outlook that highlights some of the outstanding questions about the excited state properties of Cd-chalcogenide NRs.
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Affiliation(s)
| | - Madison R Jilek
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Skylar J Sherman
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Benjamin T Hohman
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Gordana Dukovic
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80309, United States.,Materials Science and Engineering, University of Colorado Boulder, Boulder, Colorado 80303, United States
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7
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Zhang L, Qiu H, Shi R, Liu J, Ran G, Zhang W, Sun G, Long R, Fang W. Charge Transport Dynamics of Quasi-Type II Perovskite Janus Nanocrystals in High-Performance Photoconductors. J Phys Chem Lett 2023; 14:1823-1831. [PMID: 36779627 DOI: 10.1021/acs.jpclett.3c00198] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
CsPbBr3-Pb4S3Br2 Janus nanocrystals (NCs) are the only nanomaterial where the epitaxial structure of perovskite and chalcogenide materials has been realized at the nanoscale, but their exciton dynamics mechanism has not yet been thoroughly investigated or applied in photodetection applications. This work reports an attractive device performance of perovskite photoconductors based on epitaxial CsPbBr3-Pb4S3Br2 Janus NCs, as well as the carrier relaxation and transfer mechanism of the heterojunction. By a combination of transient optical absorption and quantum dynamics simulation, it is demonstrated that the photogenerated holes on CsPbBr3 can be successfully extracted by Pb4S3Br2, while the hole transfer proceeds about three times faster than energy loss and remains "hot" for about 300 fs. This feature has favorable effects on long-range charge separation and transport; therefore, the Janus NCs photoconductors exhibit an exceptional responsivity of 34.0 A W-1 and specific detectivity of 1.26 × 1014 Jones.
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Affiliation(s)
- Lin Zhang
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Key Laboratory of Energy Conversion and Storage Materials Institute, Beijing Normal University, Beijing, 100875, China
| | - Hengwei Qiu
- Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Ran Shi
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Key Laboratory of Energy Conversion and Storage Materials Institute, Beijing Normal University, Beijing, 100875, China
| | - Jinsong Liu
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing, 100875, China
| | - Guangliu Ran
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing, 100875, China
| | - Wenkai Zhang
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing, 100875, China
| | - Genban Sun
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Key Laboratory of Energy Conversion and Storage Materials Institute, Beijing Normal University, Beijing, 100875, China
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Key Laboratory of Energy Conversion and Storage Materials Institute, Beijing Normal University, Beijing, 100875, China
| | - Weihai Fang
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Key Laboratory of Energy Conversion and Storage Materials Institute, Beijing Normal University, Beijing, 100875, China
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8
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Ben-Shahar Y, Stone D, Banin U. Rich Landscape of Colloidal Semiconductor-Metal Hybrid Nanostructures: Synthesis, Synergetic Characteristics, and Emerging Applications. Chem Rev 2023; 123:3790-3851. [PMID: 36735598 PMCID: PMC10103135 DOI: 10.1021/acs.chemrev.2c00770] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Nanochemistry provides powerful synthetic tools allowing one to combine different materials on a single nanostructure, thus unfolding numerous possibilities to tailor their properties toward diverse functionalities. Herein, we review the progress in the field of semiconductor-metal hybrid nanoparticles (HNPs) focusing on metal-chalcogenides-metal combined systems. The fundamental principles of their synthesis are discussed, leading to a myriad of possible hybrid architectures including Janus zero-dimensional quantum dot-based systems and anisotropic quasi 1D nanorods and quasi-2D platelets. The properties of HNPs are described with particular focus on emergent synergetic characteristics. Of these, the light-induced charge-separation effect across the semiconductor-metal nanojunction is of particular interest as a basis for the utilization of HNPs in photocatalytic applications. The extensive studies on the charge-separation behavior and its dependence on the HNPs structural characteristics, environmental and chemical conditions, and light excitation regime are surveyed. Combining the advanced synthetic control with the charge-separation effect has led to demonstration of various applications of HNPs in different fields. A particular promise lies in their functionality as photocatalysts for a variety of uses, including solar-to-fuel conversion, as a new type of photoinitiator for photopolymerization and 3D printing, and in novel chemical and biomedical uses.
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Affiliation(s)
- Yuval Ben-Shahar
- Department of Physical Chemistry, Israel Institute for Biological Research, P.O. Box 19, Ness Ziona74100, Israel
| | - David Stone
- The Institute of Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem91904, Israel
| | - Uri Banin
- The Institute of Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem91904, Israel
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9
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Xiao H, Zhang Q, Ahmad M, Dong S, Zhang Y, Fang D, Wang X, Peng H, Lei Y, Wu G, Bai Y, Deng S, Ye F, Zeng Z. Carbonate Mediated Hole Transfer Boosting the Photocatalytic Degradation of Organic Pollutants over Carbon Nitride Nanosheets. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.122580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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10
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Gogoi H, Pathak SS, Dasgupta S, Panchakarla LS, Nath S, Datta A. Exciton Dynamics in Colloidal CdS Quantum Dots with Intense and Stokes Shifted Photoluminescence in a Single Decay Channel. J Phys Chem Lett 2022; 13:6770-6776. [PMID: 35853205 DOI: 10.1021/acs.jpclett.2c01623] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
CdS quantum dots (QDs), synthesized by a sol-gel method, exhibit significantly Stokes shifted bright photoluminescence (PL), predominantly from the trap states. Surprisingly, the PL decay at the emission maximum is single-exponential. This is an unusual observation for as-prepared QDs and indicates a narrow distribution in the nature of trap states. A closer look reveals an additional fast component for the decays at shorter emission wavelengths, presumably due to the band edge emission, which remains elusive in the steady-state spectra. Indeed, a significantly narrower and blue-shifted emission band is observed in the decay-associated spectra. The contribution of this component to the steady-state PL intensity is shown to be overwhelmed by that of the significantly stronger trap emission. Exciton dynamics in the quantum dots is elucidated using transient absorption spectra, in which the stimulated emission is observed even at low pump power.
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Affiliation(s)
- Hemen Gogoi
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Sushil Swaroop Pathak
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Souradip Dasgupta
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | | | - Sukhendu Nath
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400 094, India
| | - Anindya Datta
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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11
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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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12
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He S, Li Q, Jin T, Lian TT. Contributions of exciton fine structure and hole trapping on the hole state filling effect in the transient absorption spectra of CdSe quantum dots. J Chem Phys 2022; 156:054704. [DOI: 10.1063/5.0081192] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Sheng He
- Chemistry, Emory University, United States of America
| | - Qiuyang Li
- Physics, University of Michigan, United States of America
| | - Tao Jin
- Chemistry Department, Emory University, United States of America
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13
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Liu Y, Cullen DA, Lian T. Slow Auger Recombination of Trapped Excitons Enables Efficient Multiple Electron Transfer in CdS-Pt Nanorod Heterostructures. J Am Chem Soc 2021; 143:20264-20273. [PMID: 34797980 DOI: 10.1021/jacs.1c09125] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Solar-to-fuel conversion reaction often requires multiple proton-coupled electron transfer (PCET) processes powered by the energetic electrons and/or holes generated by the absorption of multiple photons. The effective coupling of multiple electron transfer from the light absorber with the multiple PCET reactions at the catalytic center is one of the key challenges in efficient and selective conversion of solar energy to chemical fuels. In this paper, we examine the dynamics of multiple electron transfer in quantum confined CdS nanorods with a Pt tip, in which the CdS rod functions as the light absorber and the Pt tip the catalytic center. By excitation-fluence-dependent transient absorption spectroscopic measurements, we show that the multiexciton Auger recombination rate in CdS rods follows a carrier-collision model, knA = n2(n - 1)/4k2A, with a biexciton lifetime (1/k2A) of 2.0 ± 0.2 ns. In CdS-Pt nanorods, electron transfer kinetics from the CdS conduction band edge to the Pt show negligible dependence on the excitation fluence, occurring with a half-life time of 5.6 ± 0.6 ps. The efficiency of multiple exciton dissociation by multiple electron transfer to Pt decreases from 100% in biexciton states to ∼41% at 22 exciton state due to the competition with Auger recombination. The half-lifetime of the n-charge separated state recombination (with n electrons in the Pt and n holes in the CdS) decreases from 10 μs in the single charge separated state to 42 ns in nine charge separated states. Our findings suggest the possibility of driving multielectron photocatalytic reactions under intense illumination and controlling product selectivity through multielectron transfer.
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Affiliation(s)
- Yawei Liu
- Department of Chemistry, Emory University, 1515 Dickey Drive, NE, Atlanta, Georgia 30322, United States
| | - David A Cullen
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Tianquan Lian
- Department of Chemistry, Emory University, 1515 Dickey Drive, NE, Atlanta, Georgia 30322, United States
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14
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Yang G, Liu L, Shi S, Zhang X, Liang Y, Liang G. Size‐dependent Auger recombination in
CdSe
quantum dots studied by transient absorption spectroscopy. J CHIN CHEM SOC-TAIP 2021. [DOI: 10.1002/jccs.202100161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Gaoyuan Yang
- Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices Hubei University of Arts and Science Xiangyang China
| | - Liu Liu
- Xiangyang Sunvalor Aerospace Films Co., Ltd. Xiangyang China
| | - Shuang Shi
- Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices Hubei University of Arts and Science Xiangyang China
| | - Xin Zhang
- Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices Hubei University of Arts and Science Xiangyang China
| | - Ying Liang
- Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices Hubei University of Arts and Science Xiangyang China
| | - Guijie Liang
- Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices Hubei University of Arts and Science Xiangyang China
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15
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Choi JY, Park WW, Park B, Sul S, Kwon OH, Song H. Optimal Length of Hybrid Metal–Semiconductor Nanorods for Photocatalytic Hydrogen Generation. ACS Catal 2021. [DOI: 10.1021/acscatal.1c03754] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ji Yong Choi
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Won-Woo Park
- Department of Chemistry, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Bumjin Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Soohwan Sul
- Analytical Engineering Group, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., Suwon 16678, Republic of Korea
| | - Oh-Hoon Kwon
- Department of Chemistry, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Hyunjoon Song
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
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16
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Wang H, Guo Y, Zang J, Hao H, Wang L, Liu T, Bian H, Jiang R, Wen R, Li H, Tong Y, Wang H. Nanoantennas Involved Optical Plasmonic Cavity for Improved Luminescence of Quantum Dots Light-Emitting Diodes. ACS APPLIED MATERIALS & INTERFACES 2021; 13:44760-44767. [PMID: 34505502 DOI: 10.1021/acsami.1c11995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The optical plasmonic cavity (OPC) including the metallic optical nanoantennas and a metal film exhibits extreme field enhancement for the increased spontaneous emission rate of emitters. The resonance wavelength of the OPC can be easily controlled by the volume of the OPC and the localized surface plasmonic resonances (LSPRs) of the nanoantennas, facilitating the effective coupling of OPC and the emitters. However, involving the OPC into the light emission-enhanced solution-processed devices is still a difficult challenge. The trade-off between the metallic structure of OPC and the solution procedures limits the performance enhancement of the electrical-driven devices. In this work, we construct a device-compatible OPC that allows the characterization of the carrier dynamics of quantum dot (QD) films in the real devices in-suit. The radiative recombination rate and relaxation rate of carriers in QDs are increased by the LSPR effect of the silver nanocubes for luminescence enhancement. The OPC further increases the spontaneous emission rate of QD films, achieving a Purcell factor of 166 and improving the electroluminescence of the OPC-based QD light-emitting diodes (QLEDs). The design of the OPC-involved QLEDs offers a solution for addressing the limitation of fabrication of OPC-combined solution-processed optoelectronic light sources.
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Affiliation(s)
- Hongyue Wang
- State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Shaanxi Joint Laboratory of Graphene (NPU), Northwestern Polytechnical University, Xi'an 710072, P. R. China
| | - Yangyang Guo
- State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Shaanxi Joint Laboratory of Graphene (NPU), Northwestern Polytechnical University, Xi'an 710072, P. R. China
| | - Jianyang Zang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, P. R. China
| | - Hongxing Hao
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, P. R. China
| | - Le Wang
- Shaanxi Key Laboratory for Advanced Energy Devices, Shaanxi Engineering Laboratory for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an 710119, P. R. China
| | - Taihong Liu
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, P. R. China
| | - Hongtao Bian
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, P. R. China
| | - Ruibin Jiang
- Shaanxi Key Laboratory for Advanced Energy Devices, Shaanxi Engineering Laboratory for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an 710119, P. R. China
| | - Ruijuan Wen
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, P. R. China
| | - Huixin Li
- State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Shaanxi Joint Laboratory of Graphene (NPU), Northwestern Polytechnical University, Xi'an 710072, P. R. China
| | - Yu Tong
- State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Shaanxi Joint Laboratory of Graphene (NPU), Northwestern Polytechnical University, Xi'an 710072, P. R. China
| | - Hongqiang Wang
- State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Shaanxi Joint Laboratory of Graphene (NPU), Northwestern Polytechnical University, Xi'an 710072, P. R. China
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17
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Ali F, Das S, Banerjee S, Maddala BG, Rana G, Datta A. Intense photoluminescence from Cu-doped CdSe nanotetrapods triggered by ultrafast hole capture. NANOSCALE 2021; 13:14228-14235. [PMID: 34477705 DOI: 10.1039/d1nr03833h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Brightly photoluminescent Cu-doped CdSe nanotetrapods (NTPs) have been prepared by a modified hot injection method. Their photoluminescence (PL) has a quantum yield of 38% and decays slowly over a few microseconds, while the PL in undoped NTPs has a rather small quantum yield of 1.7% and decays predominantly in tens of picoseconds, with a minor component in the nanosecond time regime. PL spectra of doped NTPs are significantly Stokes shifted compared to the band edge (BE). Efficient PL quenching by a hole scavenger confirms the oxidation state of +I for the dopant ion and establishes hole capture by this ion to be the primary event that leads to the Stokes shifted PL. A fast decay of the photoinduced absorption band, along with a similar decay in PL, observed in a femtosecond optical gating experiment, yields a time constant of about a picosecond for the hole capture from the valence band (VB) by Cu+. The remarkably long PL lifetime in the doped NTPs is ascribed to the decrease in the overlap between the wavefunctions of the photogenerated electrons and the captured hole. Hot carrier relaxation processes, triggered by excitation at energies greater than the band gap, leave their signature in a rise time of few hundreds of femtoseconds, in the ground state bleach recovery kinetics. Hence, a complete picture of exciton dynamics in the doped NTPs has been obtained using ultrafast spectroscopic techniques working in tandem.
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Affiliation(s)
- Fariyad Ali
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India.
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18
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Rhee S, Jung D, Kim D, Lee DC, Lee C, Roh J. Polarized Electroluminescence Emission in High-Performance Quantum Rod Light-Emitting Diodes via the Langmuir-Blodgett Technique. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2101204. [PMID: 34242488 DOI: 10.1002/smll.202101204] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 05/30/2021] [Indexed: 06/13/2023]
Abstract
Due to their anisotropic structure, quantum rods (QRs) feature unique properties that differ from quantum dots, such as suppression of non-radiative Auger recombination and linearly polarized light emission. Despite many potential advantages, the progress of QR-based light-emitting diodes (QR-LEDs) is left behind due to the difficulty in aligning QRs. In this study, polarized electroluminescence emission is reported in high-performance QR-LEDs by employing the Langmuir-Blodgett (LB) technique. The adoption of the LB technique successfully produces a highly dense and smooth QR film with a high degree of alignment. As a result, the aligned QR films exhibit polarized photoluminescence emission with a degree of linear polarization of 2.1. Advantageous features of the LB technique, such as nondestructiveness, precise thickness control, and the nonnecessity of an additional matrix material, allow to fabricate QR-LEDs with the same procedure as the standard spin coating-based scheme. The device is fabricated via the LB technique, which shows excellent device performance, such as the low turn-on voltage of 1.8 V, peak luminance of 56 287 cd m-2 , and peak external quantum efficiency (EQE) of 10.33%. Furthermore, these devices clearly exhibit an indication of polarized electroluminescence emission, which opens new opportunities for QRs in display technologies.
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Affiliation(s)
- Seunghyun Rhee
- SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon, 16419, Republic of Korea
- Department of Electrical Engineering and Computer Science, Inter-University Semiconductor Research Center (ISRC), Seoul National University, Seoul, 08826, Republic of Korea
| | - Dongju Jung
- SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Dahin Kim
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Doh C Lee
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Changhee Lee
- Department of Electrical Engineering and Computer Science, Inter-University Semiconductor Research Center (ISRC), Seoul National University, Seoul, 08826, Republic of Korea
| | - Jeongkyun Roh
- Department of Electrical Engineering, Pusan National University, Busan, 46241, Republic of Korea
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19
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Yang W, Liu Y, Cullen DA, McBride JR, Lian T. Harvesting Sub-Bandgap IR Photons by Photothermionic Hot Electron Transfer in a Plasmonic p-n Junction. NANO LETTERS 2021; 21:4036-4043. [PMID: 33877837 DOI: 10.1021/acs.nanolett.1c00932] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Plasmonic semiconductors are an emerging class of low-cost plasmonic materials, and the presence of a bandgap and band-bending in these materials offer new opportunities to overcome some of the limitations of plasmonic metals. Here, we demonstrate that in a plasmonic p-n heterojunction (Cu2-xSe-CdSe) the near-IR excitation (1.1 eV) of the hole plasmon in the p-Cu2-xSe phase results in rapid hot electron transfer to n-CdSe, with an energy 2.2 eV above the Fermi level. This hot electron generation and energy upconversion process can be well-described by a photothermionic mechanism, where the presence of a bandgap in p-Cu2-xSe facilitates the generation of energetic photothermal electrons. The lifetime of the transferred electrons in Cu2-xSe-CdSe can reach ∼130 ps, which is nearly 100× longer than that of its metal-semiconductor counterpart. This result demonstrates a novel approach for harvesting the sub-bandgap near IR photons using plasmonic p-n junctions and the potential advantages of plasmonic semiconductors for hot carrier-based devices.
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Affiliation(s)
- Wenxing Yang
- Department of Chemistry, Emory University, 1515 Dickey Drive Northeast, Atlanta, Georgia 30322, United States
- Department of Chemistry, Ångström Laboratory, Physical Chemistry, Uppsala University, SE-75120 Uppsala, Sweden
| | - Yawei Liu
- Department of Chemistry, Emory University, 1515 Dickey Drive Northeast, Atlanta, Georgia 30322, United States
| | - David A Cullen
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - James R McBride
- Department of Chemistry, The Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Tianquan Lian
- Department of Chemistry, Emory University, 1515 Dickey Drive Northeast, Atlanta, Georgia 30322, United States
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20
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Qin C, Guo J, Zhou Z, Liu Y, Jiang Y. Hot excitons cooling and multiexcitons Auger recombination in PbS quantum dots. NANOTECHNOLOGY 2021; 32:185701. [PMID: 33482649 DOI: 10.1088/1361-6528/abdf03] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In the past few years, lead chalcogenide quantum dots (QDs) have attracted attention as a new system with a strong quantum confinement effect. In this paper, the hot-excitons cooling and Auger recombination of multiexcitons in PbS QDs are investigated by the femtosecond time-resolved transient absorption spectroscopy. The results show that the excitons dynamics in PbS QDs are closely related to the pump-photon energy and pump-pulse energy. Multiexcitons generate when the excess energy of the absorbed photons is larger than the bandgap energy in PbS QDs. The hot-excitons cooling lifetime increases but the Auger recombination lifetime decreases as the pump-photon energy and the pump-pulse energy increase. Besides, there is a competitive relation between multiple-excitons generation and hot-excitons cooling. The dynamics results of the formation and relaxation of multiexcitons in PbS QDs would shed light on the further understanding of the interaction between excitons and photons in the optoelectronic application based on PbS QDs.
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Affiliation(s)
- Chaochao Qin
- Henan Key Laboratory of Infrared Materials & Spectrum Measures and Applications, School of Physics, Henan Normal University, Xinxiang, Henan 453007, People's Republic of China
| | - Jiajia Guo
- Henan Key Laboratory of Infrared Materials & Spectrum Measures and Applications, School of Physics, Henan Normal University, Xinxiang, Henan 453007, People's Republic of China
| | - Zhongpo Zhou
- Henan Key Laboratory of Infrared Materials & Spectrum Measures and Applications, School of Physics, Henan Normal University, Xinxiang, Henan 453007, People's Republic of China
| | - Yufang Liu
- Henan Key Laboratory of Infrared Materials & Spectrum Measures and Applications, School of Physics, Henan Normal University, Xinxiang, Henan 453007, People's Republic of China
| | - Yuhai Jiang
- Henan Key Laboratory of Infrared Materials & Spectrum Measures and Applications, School of Physics, Henan Normal University, Xinxiang, Henan 453007, People's Republic of China
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, People's Republic of China
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21
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Yang G, Shi S, Zhang X, Zhou S, Liu D, Liang Y, Chen Z, Liang G. Ultrafast photophysical process of bi-exciton Auger recombination in CuInS 2 quantum dots studied by transient-absorption spectroscopy. OPTICS EXPRESS 2021; 29:9012-9020. [PMID: 33820339 DOI: 10.1364/oe.414327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 01/19/2021] [Indexed: 06/12/2023]
Abstract
Auger recombination is an ultrafast and unnegligible photophysical process in colloidal semiconductor quantum dots (QDs) due to competition with charge separation or radiative recombination processes, pivotal for their applications ranging from bio-labeling, light-emitting diodes, QD lasing to solar energy conversion. Among diverse QDs, ternary chalcopyrite is recently receiving significant attention for its heavy-metal free property and remarkable optical performance. Given deficient understanding of the Auger process for ternary chalcopyrite QDs, CuInS2 QDs with various sizes are synthesized as a representative and the bi-exciton lifetime (τBX) is derived by virtue of ultrafast time resolved absorption spectrum. The trend of τBX varying with size is consistent with the universal scaling of τBX versus QD volume (V): τBX = γV. The scaling factor γ is 6.6 ± 0.5 ps·nm-3 for CuInS2 QDs, and the bi-exciton Auger lifetime is 4-5 times slower than typical CdSe QDs with the same volume, suggesting reduced Auger recombination rate in ternary chalcopyrite. This work facilitates clearer understanding of Auger process and provides further insight for rational design of light-harvesting and emitting devices based on ternary chalcopyrite QDs.
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22
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Xie W, Tian L, Wu K, Guo B, Gong JR. Understanding and modulating exciton dynamics of organic and low-dimensional inorganic materials in photo(electro)catalysis. J Catal 2021. [DOI: 10.1016/j.jcat.2020.12.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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23
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Burke R, Bren KL, Krauss TD. Semiconductor nanocrystal photocatalysis for the production of solar fuels. J Chem Phys 2021; 154:030901. [DOI: 10.1063/5.0032172] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Rebeckah Burke
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
| | - Kara L. Bren
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
| | - Todd D. Krauss
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
- The Institute of Optics, University of Rochester, Rochester, New York 14627, USA
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24
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Liao H, Fan Y, Lin Y, Wang K, Li R, Chen X, Zhang KHL, Yang Y. Micro-Heterogeneous Annihilation Dynamics of Self-Trapped Excitons in Hematite Single Crystals. J Phys Chem Lett 2020; 11:7867-7873. [PMID: 32864976 DOI: 10.1021/acs.jpclett.0c02330] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The Auger recombination in bulk semiconductors can quickly depopulate the charge carriers in a nonradiative way, which, fortunately, only has a detrimental impact on optoelectronic device performance under the condition of high carrier density because the restriction arising from concurrent momentum and energy conservation limits the Auger rate. Here, we surprisingly observed enhanced Auger recombination in an α-Fe2O3 single crystal, a wide bandgap semiconductor with low carrier mobility. The Auger process was ascribed to the Coulombically coupled self-trapped excitons (STEs), and the relaxation of momentum conservation due to the strong spatial localization of these STEs should account for the enhancement. The STE-density dependent kinetics suggested that the strong polaronic effect could cause a micro-heterogeneous distribution of STEs in a high-quality bulk single crystal, which also gave rise to the micro-heterogeneous annihilation dynamics, and a stochastic recombination model was developed and successfully described the STE annihilation dynamics.
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Affiliation(s)
- Hongyan Liao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Yunyan Fan
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Yumei Lin
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Kang Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Renfu Li
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures and Fujian Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China
| | - Xueyuan Chen
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures and Fujian Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China
| | - Kelvin H L Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Ye Yang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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25
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Yang W, Yang Y, Kaledin AL, He S, Jin T, McBride JR, Lian T. Surface passivation extends single and biexciton lifetimes of InP quantum dots. Chem Sci 2020; 11:5779-5789. [PMID: 32832054 PMCID: PMC7416692 DOI: 10.1039/d0sc01039a] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/15/2020] [Indexed: 01/18/2023] Open
Abstract
Indium phosphide quantum dots (InP QDs) are nontoxic nanomaterials with potential applications in photocatalytic and optoelectronic fields. Post-synthetic treatments of InP QDs are known to be essential for improving their photoluminescence quantum efficiencies (PLQEs) and device performances, but the mechanisms remain poorly understood. Herein, by applying ultrafast transient absorption and photoluminescence spectroscopies, we systematically investigate the dynamics of photogenerated carriers in InP QDs and how they are affected by two common passivation methods: HF treatment and the growth of a heterostructure shell (ZnS in this study). The HF treatment is found to improve the PLQE up to 16-20% by removing an intrinsic fast hole trapping channel (τ h,non = 3.4 ± 1 ns) in the untreated InP QDs while having little effect on the band-edge electron decay dynamics (τ e = 26-32 ns). The growth of the ZnS shell, on the other hand, is shown to improve the PLQE up to 35-40% by passivating both electron and hole traps in InP QDs, resulting in both a long-lived band-edge electron (τ e > 120 ns) and slower hole trapping lifetime (τ h,non > 45 ns). Furthermore, both the untreated and the HF-treated InP QDs have short biexciton lifetimes (τ xx ∼ 1.2 ± 0.2 ps). The growth of an ultra-thin ZnS shell (∼0.2 nm), on the other hand, can significantly extend the biexciton lifetime of InP QDs to 20 ± 2 ps, making it a passivation scheme that can improve both the single and multiple exciton lifetimes. Based on these results, we discuss the possible trap-assisted Auger processes in InP QDs, highlighting the particular importance of trap passivation for reducing the Auger recombination loss in InP QDs.
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Affiliation(s)
- Wenxing Yang
- Department of Chemistry , Emory University , 1515 Dickey Drive Northeast , Atlanta , Georgia 30322 , USA . ;
- Department of Chemistry - Ångström Laboratory , Physical Chemistry , Uppsala University , SE-75120 Uppsala , Sweden
| | - Yawei Yang
- Department of Chemistry , Emory University , 1515 Dickey Drive Northeast , Atlanta , Georgia 30322 , USA . ;
- Electronic Materials Research Laboratory , Key Laboratory of the Ministry of Education , International Center for Dielectric Research , Shaanxi Engineering Research Center of Advanced Energy Materials and Devices , School of Electronic Science and Engineering , Xi'an Jiaotong University , Xi'an 710049 , Shaanxi , P. R. China
| | - Alexey L Kaledin
- Cherry L. Emerson Center for Scientific Computation , Emory University , 1515 Dickey Drive , Atlanta , GA 30322 , USA
| | - Sheng He
- Department of Chemistry , Emory University , 1515 Dickey Drive Northeast , Atlanta , Georgia 30322 , USA . ;
| | - Tao Jin
- Department of Chemistry , Emory University , 1515 Dickey Drive Northeast , Atlanta , Georgia 30322 , USA . ;
| | - James R McBride
- Department of Chemistry , The Vanderbilt Institute of Nanoscale Science and Engineering , Vanderbilt University , Nashville , TN 37235 , USA
| | - Tianquan Lian
- Department of Chemistry , Emory University , 1515 Dickey Drive Northeast , Atlanta , Georgia 30322 , USA . ;
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26
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Kameyama T, Sugiura K, Kuwabata S, Okuhata T, Tamai N, Torimoto T. Hot electron transfer in Zn-Ag-In-Te nanocrystal-methyl viologen complexes enhanced with higher-energy photon excitation. RSC Adv 2020; 10:16361-16365. [PMID: 35498842 PMCID: PMC9052877 DOI: 10.1039/d0ra02842h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 04/16/2020] [Indexed: 01/11/2023] Open
Abstract
The dynamics of hot electron transfer from Zn–Ag–In–Te (ZAITe) nanocrystals (NCs) to adsorbed methyl viologen (MV2+) were investigated by transient absorption spectroscopy. The bleaching of the exciton peak in the ZAITe NC–MV2+ complexes evolved faster than that of ZAITe NCs. The hot electron transfer efficiency increased from 45% to 72% with increasing excitation photon energy. Zn–Ag–In–Te nanocrystals exhibited hot electron transfer to adsorbed methyl viologen, the efficiency being enhanced from 45% to 72% with an increase in the excitation photon energy.![]()
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Affiliation(s)
- Tatsuya Kameyama
- Graduate School of Engineering, Nagoya University Chikusa-ku Nagoya 464-8603 Japan.,JST, PRESTO 4-2-8 Hon-cho Kawaguchi Saitama 332-0012 Japan
| | - Kouta Sugiura
- Graduate School of Engineering, Nagoya University Chikusa-ku Nagoya 464-8603 Japan
| | - Susumu Kuwabata
- Graduate School of Engineering, Osaka University Suita Osaka 565-0871 Japan
| | - Tomoki Okuhata
- School of Science and Technology, Kwansei Gakuin University 2-1 Gakuen Sanda Hyogo 669-1337 Japan
| | - Naoto Tamai
- School of Science and Technology, Kwansei Gakuin University 2-1 Gakuen Sanda Hyogo 669-1337 Japan
| | - Tsukasa Torimoto
- Graduate School of Engineering, Nagoya University Chikusa-ku Nagoya 464-8603 Japan
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27
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Gao X, Zhang X, Yang X, Zhao L, Han B, Alanagh HR, Tang Z. Detecting electronic structure evolution of semiconductor nanocrystals by magnetic circular dichroism spectroscopy. NANOSCALE 2019; 11:19380-19386. [PMID: 31204749 DOI: 10.1039/c9nr03630j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The evolution of electronic states of nanocrystals under shape variation is hardly detected by conventional optical and electronic instruments due to the condensed electronic levels of nanocrystals. Herein, we demonstrate that magnetic circular dichroism (MCD) spectroscopy is a high-resolution method to monitor this delicate progress on account of the sensitive Zeeman response to electronic states. In particular, the MCD intensity of the first excitonic transition exponentially decreases with the shape changing from quantum dots to quantum rods owing to the increased density of valence pz state with elongation in the z direction, which contributes much less to MCD intensity compared with p±. This work provides a simple but effective strategy for understanding the electronic state evolution in various semiconductor nanomaterials.
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Affiliation(s)
- Xiaoqing Gao
- Shenzhen Key Laboratory of Flexible Memory Materials and Devices, College of Physics and Optoelectronic Engineering, Shenzhen University, Guangdong 518060, People's Republic of China
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28
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Yang W, Godin R, Kasap H, Moss B, Dong Y, Hillman SAJ, Steier L, Reisner E, Durrant JR. Electron Accumulation Induces Efficiency Bottleneck for Hydrogen Production in Carbon Nitride Photocatalysts. J Am Chem Soc 2019; 141:11219-11229. [DOI: 10.1021/jacs.9b04556] [Citation(s) in RCA: 120] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Wenxing Yang
- Department of Chemistry and Centre for Plastic Electronics, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Robert Godin
- Department of Chemistry and Centre for Plastic Electronics, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Hatice Kasap
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Benjamin Moss
- Department of Chemistry and Centre for Plastic Electronics, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Yifan Dong
- Department of Chemistry and Centre for Plastic Electronics, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Sam A. J. Hillman
- Department of Chemistry and Centre for Plastic Electronics, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Ludmilla Steier
- Department of Chemistry and Centre for Plastic Electronics, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Erwin Reisner
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - James R. Durrant
- Department of Chemistry and Centre for Plastic Electronics, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
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29
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Li Q, Lian T. Ultrafast Charge Separation in Two-Dimensional CsPbBr 3 Perovskite Nanoplatelets. J Phys Chem Lett 2019; 10:566-573. [PMID: 30642172 DOI: 10.1021/acs.jpclett.8b03610] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Two-dimensional (2D) cesium lead halide perovskite colloidal nanoplatelets show sharper excitonic absorption/emission peaks and larger absorption cross section in comparison to bulk materials and quantum dots. It remains unclear how 2D exciton and charge separation properties can be utilized to further enhance the performance of perovskite materials for optoelectrical applications. Herein, we report a study of exciton and interfacial charge-transfer dynamics of CsPbBr3 nanoplatelets via transient absorption spectroscopy. The exciton binding energy (∼260 meV) is determined via detailed spectral analysis. The exciton bleach is caused by band-edge exciton state-filling with negligible single carrier (electron or hole) contributions. Efficient charge separation can be achieved by selective electron and hole transfers to adsorbed molecular acceptors (benzoquinone and phenothiazine, respectively), and the half-life of the charge-separated state (≫100 ns) in nanoplatelet-phenothiazine complexes is >100 fold longer than that in quantum dot-phenothiazine complexes. Our results suggest that CsPbBr3 nanoplatelets are promising materials for photocatalysis and photovoltaic applications.
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Affiliation(s)
- Qiuyang Li
- Department of Chemistry , Emory University , 1515 Dickey Drive, NE , Atlanta , Georgia 30322 , United States
| | - Tianquan Lian
- Department of Chemistry , Emory University , 1515 Dickey Drive, NE , Atlanta , Georgia 30322 , United States
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Philbin JP, Rabani E. Electron-Hole Correlations Govern Auger Recombination in Nanostructures. NANO LETTERS 2018; 18:7889-7895. [PMID: 30403875 DOI: 10.1021/acs.nanolett.8b03715] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The fast nonradiative decay of multiexcitonic states via Auger recombination is a fundamental process affecting a variety of applications based on semiconductor nanostructures. From a theoretical perspective, the description of Auger recombination in confined semiconductor nanostructures is a challenging task due to the large number of valence electrons and exponentially growing number of excited excitonic and biexcitonic states that are coupled by the Coulomb interaction. These challenges have restricted the treatment of Auger recombination to simple, noninteracting electron-hole models. Herein we present a novel approach for calculating Auger recombination lifetimes in confined nanostructures having thousands to tens of thousands of electrons, explicitly including electron-hole interactions. We demonstrate that the inclusion of electron-hole correlations are imperative to capture the correct scaling of the Auger recombination lifetime with the size and shape of the nanostructure. In addition, correlation effects are required to obtain quantitatively accurate lifetimes even for systems smaller than the exciton Bohr radius. Neglecting such correlations can result in lifetimes that are two orders of magnitude too long. We establish the utility of the new approach for CdSe quantum dots of varying sizes and for CdSe nanorods of varying diameters and lengths. Our new approach is the first theoretical method to postdict the experimentally known "universal volume scaling law" for quantum dots and makes novel predictions for the scaling of the Auger recombination lifetimes in nanorods.
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Affiliation(s)
- John P Philbin
- Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Eran Rabani
- Department of Chemistry , University of California , Berkeley , California 94720 , United States
- The Sackler Center for Computational Molecular and Materials Science , Tel Aviv University , Tel Aviv 69978 , Israel
- Materials Science Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
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31
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Miao Y, Gu C, Zhu Y, Yu B, Shen Y, Cong H. Recent Progress in Fluorescence Imaging of the Near‐Infrared II Window. Chembiochem 2018; 19:2522-2541. [DOI: 10.1002/cbic.201800466] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Indexed: 01/16/2023]
Affiliation(s)
- Yawei Miao
- Institute of Biomedical Materials and EngineeringCollege of Materials Science and EngineeringLaboratory for New Fiber Materials and Modern Textile, Growing Base for State Key LaboratoryCollege of Chemistry and Chemical EngineeringQingdao University Qingdao 266071 P.R. China
| | - Chuantao Gu
- Institute of Biomedical Materials and EngineeringCollege of Materials Science and EngineeringLaboratory for New Fiber Materials and Modern Textile, Growing Base for State Key LaboratoryCollege of Chemistry and Chemical EngineeringQingdao University Qingdao 266071 P.R. China
| | - Yaowei Zhu
- Institute of Biomedical Materials and EngineeringCollege of Materials Science and EngineeringLaboratory for New Fiber Materials and Modern Textile, Growing Base for State Key LaboratoryCollege of Chemistry and Chemical EngineeringQingdao University Qingdao 266071 P.R. China
| | - Bing Yu
- Institute of Biomedical Materials and EngineeringCollege of Materials Science and EngineeringLaboratory for New Fiber Materials and Modern Textile, Growing Base for State Key LaboratoryCollege of Chemistry and Chemical EngineeringQingdao University Qingdao 266071 P.R. China
| | - Youqing Shen
- Institute of Biomedical Materials and EngineeringCollege of Materials Science and EngineeringLaboratory for New Fiber Materials and Modern Textile, Growing Base for State Key LaboratoryCollege of Chemistry and Chemical EngineeringQingdao University Qingdao 266071 P.R. China
- Center for Bionanoengineering and Key Laboratory of Biomass, Chemical Engineering of Ministry of EducationCollege of Chemical and Biological EngineeringZhejiang University Hangzhou 310027 P.R. China
| | - Hailin Cong
- Institute of Biomedical Materials and EngineeringCollege of Materials Science and EngineeringLaboratory for New Fiber Materials and Modern Textile, Growing Base for State Key LaboratoryCollege of Chemistry and Chemical EngineeringQingdao University Qingdao 266071 P.R. China
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32
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Li Q, Zhao F, Qu C, Shang Q, Xu Z, Yu L, McBride JR, Lian T. Two-Dimensional Morphology Enhances Light-Driven H 2 Generation Efficiency in CdS Nanoplatelet-Pt Heterostructures. J Am Chem Soc 2018; 140:11726-11734. [PMID: 30145886 DOI: 10.1021/jacs.8b06100] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Light-driven H2 generation using semiconductor nanocrystal heterostructures has attracted intense recent interest because of the ability to rationally improve their performance by tailoring their size, composition, and morphology. In zero- and one-dimensional nanomaterials, the lifetime of the photoinduced charge-separated state is still too short for H2 evolution reaction, limiting the solar-to-H2 conversion efficiency. Here we report that using two-dimensional (2D) CdS nanoplatelet (NPL)-Pt heterostructures, H2 generation internal quantum efficiency (IQE) can exceed 40% at pH 8.8-13 and approach unity at pH 14.7. The near unity IQE at pH 14.7 is similar to those reported for 1D nanorods and can be attributed to the irreversible hole removal by OH-. At pH < 13, the IQE of 2D NPL-Pt is significantly higher than those in 1D nanorods. Detailed time-resolved spectroscopic studies and modeling of the elementary charge separation and recombination processes show that, compared to 1D nanorods, 2D morphology extends charge-separated state lifetime and may play a dominant role in enhancing the H2 generation efficiency. This work provides a new approach for designing nanostructures for efficient light-driven H2 generation.
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Affiliation(s)
- Qiuyang Li
- Department of Chemistry , Emory University , 1515 Dickey Drive, Northeast , Atlanta , Georgia 30322 , United States
| | - Fengjiao Zhao
- State Key Laboratory of Molecular Reaction Dynamics , Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian 116023 , China
| | - Chen Qu
- Department of Chemistry , Emory University , 1515 Dickey Drive, Northeast , Atlanta , Georgia 30322 , United States
| | - Qiongyi Shang
- Department of Chemistry , Emory University , 1515 Dickey Drive, Northeast , Atlanta , Georgia 30322 , United States
| | - Zihao Xu
- Department of Chemistry , Emory University , 1515 Dickey Drive, Northeast , Atlanta , Georgia 30322 , United States
| | - Li Yu
- Department of Chemistry , Emory University , 1515 Dickey Drive, Northeast , Atlanta , Georgia 30322 , United States
| | - James R McBride
- Department of Chemistry, The Vanderbilt Institute of Nanoscale Science and Engineering , Vanderbilt University , Nashville , Tennessee 37235 , United States
| | - Tianquan Lian
- Department of Chemistry , Emory University , 1515 Dickey Drive, Northeast , Atlanta , Georgia 30322 , United States
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33
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Ben-Shahar Y, Philbin JP, Scotognella F, Ganzer L, Cerullo G, Rabani E, Banin U. Charge Carrier Dynamics in Photocatalytic Hybrid Semiconductor-Metal Nanorods: Crossover from Auger Recombination to Charge Transfer. NANO LETTERS 2018; 18:5211-5216. [PMID: 29985622 DOI: 10.1021/acs.nanolett.8b02169] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Hybrid semiconductor-metal nanoparticles (HNPs) manifest unique, synergistic electronic and optical properties as a result of combining semiconductor and metal physics via a controlled interface. These structures can exhibit spatial charge separation across the semiconductor-metal junction upon light absorption, enabling their use as photocatalysts. The combination of the photocatalytic activity of the metal domain with the ability to generate and accommodate multiple excitons in the semiconducting domain can lead to improved photocatalytic performance because injecting multiple charge carriers into the active catalytic sites can increase the quantum yield. Herein, we show a significant metal domain size dependence of the charge carrier dynamics as well as the photocatalytic hydrogen generation efficiencies under nonlinear excitation conditions. An understanding of this size dependence allows one to control the charge carrier dynamics following the absorption of light. Using a model hybrid semiconductor-metal CdS-Au nanorod system and combining transient absorption and hydrogen evolution kinetics, we reveal faster and more efficient charge separation and transfer under multiexciton excitation conditions for large metal domains compared to small ones. Theoretical modeling uncovers a competition between the kinetics of Auger recombination and charge separation. A crossover in the dominant process from Auger recombination to charge separation as the metal domain size increases allows for effective multiexciton dissociation and harvesting in large metal domain HNPs. This was also found to lead to relative improvement of their photocatalytic activity under nonlinear excitation conditions.
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Affiliation(s)
- Yuval Ben-Shahar
- The Institute of Chemistry and Center for Nanoscience and Nanotechnology , The Hebrew University of Jerusalem , Jerusalem 91904 , Israel
| | - John P Philbin
- Department of Chemistry , University of California and Lawrence Berkeley National Laboratory , Berkeley , California 94720-1460 , United States
| | | | - Lucia Ganzer
- IFN-CNR, Dipartimento di Fisica , Politecnico di Milano , Milan 20133 , Italy
| | - Giulio Cerullo
- IFN-CNR, Dipartimento di Fisica , Politecnico di Milano , Milan 20133 , Italy
| | - Eran Rabani
- Department of Chemistry , University of California and Lawrence Berkeley National Laboratory , Berkeley , California 94720-1460 , United States
- The Sackler Institute for Computational Molecular and Materials Science , Tel Aviv University , Tel Aviv , Israel 69978
| | - Uri Banin
- The Institute of Chemistry and Center for Nanoscience and Nanotechnology , The Hebrew University of Jerusalem , Jerusalem 91904 , Israel
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Sekhar MC, Paul S, De A, Samanta A. An Ultrafast Transient Absorption Study of Charge Separation and Recombination Dynamics in CdSe QDs and Methyl Viologen: Dependence on Surface Stoichiometry. ChemistrySelect 2018. [DOI: 10.1002/slct.201800313] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- M. Chandra Sekhar
- School of Chemistry; University of Hyderabad; Hyderabad 500046 India
| | - Sneha Paul
- School of Chemistry; University of Hyderabad; Hyderabad 500046 India
| | - Apurba De
- School of Chemistry; University of Hyderabad; Hyderabad 500046 India
| | - Anunay Samanta
- School of Chemistry; University of Hyderabad; Hyderabad 500046 India
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35
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Li Q, Lian T. A model for optical gain in colloidal nanoplatelets. Chem Sci 2018; 9:728-734. [PMID: 29629142 PMCID: PMC5870475 DOI: 10.1039/c7sc04294a] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 11/13/2017] [Indexed: 12/19/2022] Open
Abstract
Optical gain in CdSe nanoplatelets is shown to be independent on their lateral size and can be explained by a new optical gain model for 2D nanoplatelets.
Cadmium chalcogenide nanoplatelets (NPLs) and their heterostructures have been reported to have low gain thresholds and large gain coefficients, showing great potential for lasing applications. However, the further improvement of the optical gain properties of NPLs is hindered by a lack of models that can account for their optical gain characteristics and predict their dependence on the properties (such as lateral size, concentration, and/or optical density). Herein, we report a systematic study of optical gain (OG) in 4-monolayer thick CdSe NPLs by both transient absorption spectroscopy study of colloidal solutions and amplified spontaneous emission (ASE) measurement of thin films. We showed that comparing samples with the same optical density at the excitation, the OG threshold is not dependent of the NPL lateral area, while the saturation gain amplitude is dependent on the NPL lateral area when comparing samples with the same optical density at the excitation wavelength. Both the OG and ASE thresholds increase with the optical density at the excitation wavelength for samples of the same NPL thickness and lateral area. We proposed an OG model for NPLs that can successfully account for the observed lateral area and optical density dependences. The model reveals that OG originates from stimulated emission from the bi-exciton states and the OG threshold is reached when the average number of excitons per NPL is about half the occupation of the band-edge exciton states. The model can also rationalize the much lower OG thresholds in the NPLs compared to QDs. This work provides a microscopic understanding of the dependence of the OG properties on the morphology of the colloidal nanocrystals and important guidance for the rational optimization of the lasing performance of NPLs and other 1- and 2-dimensional nanocrystals.
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Affiliation(s)
- Qiuyang Li
- Department of Chemistry , Emory University , 1515 Dickey Drive, NE , Atlanta , GA 30322 , USA .
| | - Tianquan Lian
- Department of Chemistry , Emory University , 1515 Dickey Drive, NE , Atlanta , GA 30322 , USA .
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36
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Mondal N, De A, Samanta A. All-inorganic perovskite nanocrystal assisted extraction of hot electrons and biexcitons from photoexcited CdTe quantum dots. NANOSCALE 2018; 10:639-645. [PMID: 29238789 DOI: 10.1039/c7nr07830g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Excitation of semiconductor quantum dots (QDs) by photons possessing energy higher than the band-gap creates a hot electron-hole pair, which releases its excess energy as waste heat or under certain conditions (when hν > 2Eg) produces multiple excitons. Extraction of these hot carriers and multiple excitons is one of the key strategies for enhancing the efficiency of QD-based photovoltaic devices. However, this is a difficult task as competing carrier cooling and relaxation of multiple excitons (through Auger recombination) are ultrafast processes. Herein, we study the potential of all-inorganic perovskite nanocrystals (NCs) of CsPbX3 (X = Cl, Br) as harvesters of these short-lived species from photo-excited CdTe QDs. The femtosecond transient absorption measurements show CsPbX3 mediated extraction of both hot and thermalized electrons of the QDs (under a low pump power) and (under a high pump fluence) extraction of multiple excitons prior to their Auger assisted recombination. A faster timescale of thermalized electron transfer (∼2 ps) and a higher extraction efficiency of hot electrons (∼60%) are observed in the presence of CsPbBr3. These observations demonstrate the potential of all-inorganic perovskite NCs in the extraction of these short-lived energy rich species implying that complexes of the QDs and perovskite NCs are better suited for improving the efficiency of QD-sensitized solar cells.
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Affiliation(s)
- Navendu Mondal
- School of Chemistry, University of Hyderabad, Hyderabad-500046, India.
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37
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Wang JH, Liang GJ, Wu KF. Long-lived Single Excitons, Trions, and Biexcitons in CdSe/CdTe Type-II Colloidal Quantum Wells. CHINESE J CHEM PHYS 2017. [DOI: 10.1063/1674-0068/30/cjcp1711206] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Jun-hui Wang
- State Key Laboratory of Molecular Reaction Dynamics and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Gui-jie Liang
- State Key Laboratory of Molecular Reaction Dynamics and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Kai-feng Wu
- State Key Laboratory of Molecular Reaction Dynamics and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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38
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Choi JY, Jeong D, Lee SJ, Kang DG, Kim SK, Nam KM, Song H. Engineering Reaction Kinetics by Tailoring the Metal Tips of Metal-Semiconductor Nanodumbbells. NANO LETTERS 2017; 17:5688-5694. [PMID: 28850244 DOI: 10.1021/acs.nanolett.7b02582] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Semiconductor-metal hybrid nanostructures are one of the best model catalysts for understanding photocatalytic hydrogen generation. To investigate the optimal structure of metal cocatalysts, metal-CdSe-metal nanodumbbells were synthesized with three distinct sets of metal tips, Pt-CdSe-Pt, Au-CdSe-Au, and Au-CdSe-Pt. Photoelectrochemical responses and transient absorption spectra showed that the competition between the charge recombination at the metal-CdSe interface and the water reduction on the metal surface is a detrimental factor for the apparent hydrogen evolution rate. For instance, a large recombination rate (krec) at the Pt-CdSe interface limits the quantum yield of hydrogen generation despite a superior water reduction rate (kWR) on the Pt surface. To suppress the recombination process, Pt was selectively deposited onto the Au tips of Au-CdSe-Au nanodumbbells in which the krec was diminished at the Au-CdSe interface, and the large kWR was maintained on the Pt surface. As a result, the optimal structure of the Pt-coated Au-CdSe-Au nanodumbbells reached a quantum yield of 4.84%. These findings successfully demonstrate that the rational design of a metal cocatalyst and metal-semiconductor interface can additionally enhance the catalytic performance of the photochemical hydrogen generation reactions.
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Affiliation(s)
- Ji Yong Choi
- Department of Chemistry, Korea Advanced Institute of Science and Technology , Daejeon 34141, Republic of Korea
| | - Dahyi Jeong
- Department of Chemistry, Korea Advanced Institute of Science and Technology , Daejeon 34141, Republic of Korea
| | - Seon Joo Lee
- Advanced Materials Division, Korea Research Institute of Chemical Technology , 141 Gajeong-ro, Yuseong-gu, Daejeon 34114, Republic of Korea
| | - Dong-Gu Kang
- Department of Chemistry, Korea Advanced Institute of Science and Technology , Daejeon 34141, Republic of Korea
| | - Sang Kyu Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology , Daejeon 34141, Republic of Korea
| | - Ki Min Nam
- Department of Chemistry, Mokpo National University , Jeonnam 58554, Republic of Korea
| | - Hyunjoon Song
- Department of Chemistry, Korea Advanced Institute of Science and Technology , Daejeon 34141, Republic of Korea
- Center for Nanomaterials and Chemical Reactions, Institute for Basic Science , Daejeon 34141, Republic of Korea
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39
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Stolle CJ, Lu X, Yu Y, Schaller RD, Korgel BA. Efficient Carrier Multiplication in Colloidal Silicon Nanorods. NANO LETTERS 2017; 17:5580-5586. [PMID: 28762274 DOI: 10.1021/acs.nanolett.7b02386] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Auger recombination lifetimes, absorption cross sections, and the quantum yields of carrier multiplication (CM), or multiexciton generation (MEG), were determined for solvent-dispersed silicon (Si) nanorods using transient absorption spectroscopy (TAS). Nanorods with an average diameter of 7.5 nm and aspect ratios of 6.1, 19.3, and 33.2 were examined. Colloidal Si nanocrystals of similar diameters were also studied for comparison. The nanocrystals and nanorods were passivated with organic ligands by hydrosilylation to prevent surface oxidation and limit the effects of surface trapping of photoexcited carriers. All samples used in the study exhibited relatively efficient photoluminescence. The Auger lifetimes increased with nanorod length, and the nanorods exhibited higher CM quantum yield and efficiency than the nanocrystals with a similar band gap energy Eg. Beyond a critical length, the CM quantum yield decreases. Nanorods with the aspect ratio of 19.3 had the highest CM quantum yield of 1.6 ± 0.2 at 2.9Eg, which corresponded to a multiexciton yield that was twice as high as observed for the spherical nanocrystals.
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Affiliation(s)
- Carl Jackson Stolle
- McKetta Department of Chemical Engineering, Texas Materials Institute, Center for Nano- and Molecular Science and Technology, The University of Texas at Austin , Austin, Texas 78712, United States
| | - Xiaotang Lu
- McKetta Department of Chemical Engineering, Texas Materials Institute, Center for Nano- and Molecular Science and Technology, The University of Texas at Austin , Austin, Texas 78712, United States
| | - Yixuan Yu
- McKetta Department of Chemical Engineering, Texas Materials Institute, Center for Nano- and Molecular Science and Technology, The University of Texas at Austin , Austin, Texas 78712, United States
| | - Richard D Schaller
- Department of Chemistry, Northwestern University , Evanston, Illinois 60439, United States
- Center for Nanoscale Materials, Argonne National Laboratories , Argonne, Illinois 60439, United States
| | - Brian A Korgel
- McKetta Department of Chemical Engineering, Texas Materials Institute, Center for Nano- and Molecular Science and Technology, The University of Texas at Austin , Austin, Texas 78712, United States
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40
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Lee S, Wang Y, Liu Y, Lee D, Lee K, Lee DC, Lian T. Exciton dynamics in cation-exchanged CdSe/PbSe nanorods: The role of defects. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.04.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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41
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42
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Ponseca CS, Chábera P, Uhlig J, Persson P, Sundström V. Ultrafast Electron Dynamics in Solar Energy Conversion. Chem Rev 2017; 117:10940-11024. [DOI: 10.1021/acs.chemrev.6b00807] [Citation(s) in RCA: 211] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Carlito S. Ponseca
- Division
of Chemical Physics, Chemical Center, and ‡Theoretical Chemistry Division,
Chemical Center, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Pavel Chábera
- Division
of Chemical Physics, Chemical Center, and ‡Theoretical Chemistry Division,
Chemical Center, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Jens Uhlig
- Division
of Chemical Physics, Chemical Center, and ‡Theoretical Chemistry Division,
Chemical Center, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Petter Persson
- Division
of Chemical Physics, Chemical Center, and ‡Theoretical Chemistry Division,
Chemical Center, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Villy Sundström
- Division
of Chemical Physics, Chemical Center, and ‡Theoretical Chemistry Division,
Chemical Center, Lund University, Box 124, Lund SE-221 00, Sweden
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43
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Wang HI, Bonn M, Cánovas E. Boosting Biexciton Collection Efficiency at Quantum Dot-Oxide Interfaces by Hole Localization at the Quantum Dot Shell. J Phys Chem Lett 2017; 8:2654-2658. [PMID: 28558226 DOI: 10.1021/acs.jpclett.7b00966] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Harvesting multiexcitons from semiconductor quantum dots (QDs) has been proposed as a path toward photovoltaic efficiencies beyond the Shockley-Queisser limit. Although multiexciton generation efficiencies have been quantified extensively in QD structures, the challenge of actually collecting multiple excitons at electrodes-a prerequisite for high-efficiency solar cell devices-has received less attention. Here, we demonstrate that multiexciton collection (MEC) at the PbS QD/mesoporous SnO2 interface can be boosted 5-fold from ∼15 to reach ∼80% quantum yield, by partial localization of holes in a QD molecular capping shell. The resulting weakened Coulombic interactions give rise to reduced Auger recombination rates within the molecularly capped QDs, so that biexciton Auger relaxation, competing with MEC, is strongly suppressed. These results not only highlight the importance of surface chemistry and energetics at QD/ligand interfaces for multiexciton extraction but also provide clear design principles for realizing the benefits of MEG in sensitized systems exploited in solar cells and fuel geometries.
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Affiliation(s)
- Hai I Wang
- Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany
- Graduate School of Material Science in Mainz, University of Mainz , Staudingerweg 9, 55128 Mainz, Germany
| | - Mischa Bonn
- Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany
| | - Enrique Cánovas
- Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany
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Abstract
Atomically precise gold nanocluster based on linear assembly of repeating icosahedrons (clusters of clusters) is a unique type of linear nanostructure, which exhibits strong near-infrared absorption as their free electrons are confined in a one-dimensional quantum box. Little is known about the carrier dynamics in these nanoclusters, which limit their energy-related applications. Here, we reported the observation of exciton localization in triicosahedral Au37 nanoclusters (0.5 nm in diameter and 1.6 nm in length) by measuring femtosecond and nanosecond carrier dynamics. Upon photoexcitation to S1 electronic state, electrons in Au37 undergo ∼100-ps localization from the two vertexes of three icosahedrons to one vertex, forming a long-lived S1* state. Such phenomenon is not observed in Au25 (dimer) and Au13 (monomer) consisting of two and one icosahedrons, respectively. We have further observed temperature dependence on the localization process, which proves it is thermally driven. Two excited-state vibration modes with frequencies of 20 and 70 cm-1 observed in the kinetic traces are assigned to the axial and radial breathing modes, respectively. The electron localization is ascribed to the structural distortion of Au37 in the excited state induced by the strong coherent vibrations. The observed electron localization phenomenon provides unique physical insight into one-dimensional gold nanoclusters and other nanostructures, which will advance their applications in solar-energy storage and conversion.
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45
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Li Q, Lian T. Area- and Thickness-Dependent Biexciton Auger Recombination in Colloidal CdSe Nanoplatelets: Breaking the "Universal Volume Scaling Law". NANO LETTERS 2017; 17:3152-3158. [PMID: 28418671 DOI: 10.1021/acs.nanolett.7b00587] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Colloidal nanoplatelets (NPLs) have shown great potentials for lasing applications due to their sharp absorption and emission peaks, large absorption cross sections, large radiative decay rates, and long multiexciton lifetimes. How multiexciton lifetimes depend on material dimensions remains unknown in two-dimensional (2D) materials, despite being a key parameter affecting optical gain threshold and many other properties. Herein, we report a study of room-temperature biexciton Auger recombination time of CdSe NPLs as a function of thickness and lateral area. Comparison of all NPLs shows that the biexciton lifetime does not increase linearly with volume, unlike previously reported "universal volume scaling law" for quantum dots. For NPLs of the same thickness (∼1.8 nm), the biexciton lifetime increase linearly with their lateral area (from 143.7 ± 12.6 to 320.1 ± 17.1 ps when the area increases from 90.5 ± 21.4 to 234.2 ± 41.9 nm2). The biexciton lifetime depends linearly on (1/Ek(e))7/2 (Ek(e) is the electron confinement energy) or nearly linearly on d7 (d is NPL thickness). The observed dependence is consistent with a model in which biexciton Auger recombination rate scales with the product of exciton binary collision frequency and Auger recombination probability in biexciton complexes. The linear increase of Auger lifetimes with NPL lateral areas reflects a 1/area dependence of the binary collision frequency for 2D excitons and the thickness-dependent biexciton Auger recombination time is attributed to its strong dependence on the degree of quantum confinement. This model may be generally applicable to exciton Auger recombination in quantum confined 1D and 2D nanomaterials.
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Affiliation(s)
- Qiuyang Li
- Department of Chemistry, Emory University , 1515 Dickey Drive, NE, Atlanta, Georgia 30322, United States
| | - Tianquan Lian
- Department of Chemistry, Emory University , 1515 Dickey Drive, NE, Atlanta, Georgia 30322, United States
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Li JX, Ye C, Li XB, Li ZJ, Gao XW, Chen B, Tung CH, Wu LZ. A Redox Shuttle Accelerates O 2 Evolution of Photocatalysts Formed In Situ under Visible Light. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1606009. [PMID: 28218472 DOI: 10.1002/adma.201606009] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 12/15/2016] [Indexed: 06/06/2023]
Abstract
A redox shuttle strategy is demonstrated to be a promising approach to accelerate hole removal for efficient O2 production with mesoporous graphitic carbon nitride, WO3 , BiVO4 , NiTi-LDH, and Ag3 PO4 water-oxidation catalysts under visible-light irradiation.
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Affiliation(s)
- Jia-Xin Li
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Chen Ye
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Xu-Bing Li
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Zhi-Jun Li
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Xue-Wang Gao
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Bin Chen
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Chen-Ho Tung
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Li-Zhu Wu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China
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Li Q, Xu Z, McBride JR, Lian T. Low Threshold Multiexciton Optical Gain in Colloidal CdSe/CdTe Core/Crown Type-II Nanoplatelet Heterostructures. ACS NANO 2017; 11:2545-2553. [PMID: 28157330 DOI: 10.1021/acsnano.6b08674] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Colloidal cadmium chalcogenide core/crown type-II nanoplatelet heterostructures, such as CdSe/CdTe, are promising materials for lasing and light-emitting applications. Their rational design and improvement requires the understanding of the nature of single- and multiexciton states. Using pump fluence and wavelength-dependent ultrafast transient absorption spectroscopy, we have identified three spatially and energetically distinct excitons (in the order of increasing energy): interface-localized charge transfer exciton (XCT, with electron in the CdSe core bound to the hole in the CdTe crown), and CdTe crown-localized XCdTe and CdSe core-localized XCdSe excitons. These exciton levels can be filled sequentially, with each accommodating two excitons (due to electron spin degeneracy) to generate one to six exciton states (with lifetimes of ≫1000, 209, 43.5, 11.8, 5.8, and 4.5 ps, respectively). The spatial separation of these excitons prolongs the lifetime of multiexciton states. Optical gain was observed in tri- (XXCTXCdTe) and four (XXCTXXCdTe) exciton states. Because of the large absorption cross section of nanoplatelets, an optical gain threshold as low as ∼43 μJ/cm2 can be achieved at 550 nm excitation for a colloidal solution sample. This low gain threshold and the long triexciton (gain) lifetime suggest potential applications of these 2D type-II heterostructures as low threshold lasing materials.
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Affiliation(s)
- Qiuyang Li
- Department of Chemistry, Emory University , 1515 Dickey Drive, NE, Atlanta, Georgia 30322, United States
| | - Zihao Xu
- Department of Chemistry, Emory University , 1515 Dickey Drive, NE, Atlanta, Georgia 30322, United States
| | - James R McBride
- Department of Chemistry, The Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University , Nashville, Tennessee 37235, United States
| | - Tianquan Lian
- Department of Chemistry, Emory University , 1515 Dickey Drive, NE, Atlanta, Georgia 30322, United States
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Pavlopoulos NG, Dubose JT, Liu Y, Huang X, Pinna N, Willinger MG, Lian T, Char K, Pyun J. Type I vs. quasi-type II modulation in CdSe@CdS tetrapods: ramifications for noble metal tipping. CrystEngComm 2017. [DOI: 10.1039/c7ce01558e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report on noble metal tipping of heterostructured nanocrystals (NCs) of CdSe@CdS tetrapods (TPs) as a chemical reaction to manifest energetic differences between type I and quasi-type II heterojunctions.
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Affiliation(s)
| | - Jeffrey T. Dubose
- Department of Chemistry and Biochemistry
- University of Arizona
- Tucson
- USA
| | - Yawei Liu
- Department of Chemistry
- Emory University
- Atlanta
- USA
| | - Xing Huang
- Institut fur Chemie
- Humboldt-Universitat zu Berlin
- 12489 Berlin
- Germany
| | - Nicola Pinna
- Department of Inorganic Chemistry
- Fritz Haber Institute of the Max Planck Society
- Berlin
- Germany
| | | | | | - Kookheon Char
- World Class University Program for Chemical Convergence for Energy and Environment
- School of Chemical and Biological Engineering
- Seoul National University
- Seoul 151-744
- Korea
| | - Jeffrey Pyun
- Department of Chemistry and Biochemistry
- University of Arizona
- Tucson
- USA
- World Class University Program for Chemical Convergence for Energy and Environment
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Qiu F, Han Z, Peterson JJ, Odoi MY, Sowers KL, Krauss TD. Photocatalytic Hydrogen Generation by CdSe/CdS Nanoparticles. NANO LETTERS 2016; 16:5347-5352. [PMID: 27478995 DOI: 10.1021/acs.nanolett.6b01087] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The photocatalytic hydrogen (H2) production activity of various CdSe semiconductor nanoparticles was compared including CdSe and CdSe/CdS quantum dots (QDs), CdSe quantum rods (QRs), and CdSe/CdS dot-in-rods (DIRs). With equivalent photons absorbed, the H2 generation activity orders as CdSe QDs ≫ CdSe QRs > CdSe/CdS QDs > CdSe/CdS DIRs, which is surprisingly the opposite of the electron-hole separation efficiency. Calculations of photoexcited surface charge densities are positively correlated with the H2 production rate and suggest the size of the nanoparticle plays a critical role in determining the relative efficiency of H2 production.
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Affiliation(s)
- Fen Qiu
- Departments of Chemistry and ‡The Institute of Optics, University of Rochester , Rochester, New York 14627, United States
| | - Zhiji Han
- Departments of Chemistry and ‡The Institute of Optics, University of Rochester , Rochester, New York 14627, United States
| | - Jeffrey J Peterson
- Departments of Chemistry and ‡The Institute of Optics, University of Rochester , Rochester, New York 14627, United States
| | - Michael Y Odoi
- Departments of Chemistry and ‡The Institute of Optics, University of Rochester , Rochester, New York 14627, United States
| | - Kelly L Sowers
- Departments of Chemistry and ‡The Institute of Optics, University of Rochester , Rochester, New York 14627, United States
| | - Todd D Krauss
- Departments of Chemistry and ‡The Institute of Optics, University of Rochester , Rochester, New York 14627, United States
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Harris RD, Bettis Homan S, Kodaimati M, He C, Nepomnyashchii AB, Swenson NK, Lian S, Calzada R, Weiss EA. Electronic Processes within Quantum Dot-Molecule Complexes. Chem Rev 2016; 116:12865-12919. [PMID: 27499491 DOI: 10.1021/acs.chemrev.6b00102] [Citation(s) in RCA: 171] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The subject of this review is the colloidal quantum dot (QD) and specifically the interaction of the QD with proximate molecules. It covers various functions of these molecules, including (i) ligands for the QDs, coupled electronically or vibrationally to localized surface states or to the delocalized states of the QD core, (ii) energy or electron donors or acceptors for the QDs, and (iii) structural components of QD assemblies that dictate QD-QD or QD-molecule interactions. Research on interactions of ligands with colloidal QDs has revealed that ligands determine not only the excited state dynamics of the QD but also, in some cases, its ground state electronic structure. Specifically, the article discusses (i) measurement of the electronic structure of colloidal QDs and the influence of their surface chemistry, in particular, dipolar ligands and exciton-delocalizing ligands, on their electronic energies; (ii) the role of molecules in interfacial electron and energy transfer processes involving QDs, including electron-to-vibrational energy transfer and the use of the ligand shell of a QD as a semipermeable membrane that gates its redox activity; and (iii) a particular application of colloidal QDs, photoredox catalysis, which exploits the combination of the electronic structure of the QD core and the chemistry at its surface to use the energy of the QD excited state to drive chemical reactions.
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Affiliation(s)
- Rachel D Harris
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Stephanie Bettis Homan
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Mohamad Kodaimati
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Chen He
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | | | - Nathaniel K Swenson
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Shichen Lian
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Raul Calzada
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Emily A Weiss
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
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