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Cho K, Park Y, Jo H, Seo S, Moon J, Lee SJ, Park SY, Yoon SJ, Park J. Identification and Dynamics of Microsecond Long-Lived Charge Carriers for CsPbBr 3 Perovskite Quantum Dots, Featuring Ambient Long-Term Stability. J Phys Chem Lett 2024; 15:5795-5803. [PMID: 38780120 DOI: 10.1021/acs.jpclett.4c01024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
We analyze the stability and photophysical dynamics of CsPbBr3 perovskite quantum dots (PeQDs), fabricated under mild synthetic conditions and embedded in an amorphous silica (SiOx) matrix (CsPbBr3@SiOx), underscoring their sustained performance in ambient conditions for over 300 days with minimal optical degradation. However, this stability comes at the cost of a reduced photoluminescence efficiency. Time-resolved spectroscopic analyses, including flash-photolysis time-resolved microwave conductivity and time-resolved photoluminescence, show that excitons in CsPbBr3@SiOx films decay within 2.5 ns, while charge carriers recombine over approximately 230 ns. This longevity of the charge carriers is due to photoinduced electron transfer to the SiOx matrix, enabling hole retention. The measured hole mobility in these PeQDs is 0.880 cm2 V-1 s-1, underscoring their potential in optoelectronic applications. This study highlights the role of the silica matrix in enhancing the durability of PeQDs in humid environments and modifying exciton dynamics and photoluminescence, providing valuable insights for developing robust optoelectronic materials.
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Affiliation(s)
- Kayoung Cho
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Youmin Park
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Hyeonyeong Jo
- Department of Chemistry, Yeungnam University, Gyeongsan 38541, Republic of Korea
| | - Sumi Seo
- Department of Chemistry, Yeungnam University, Gyeongsan 38541, Republic of Korea
| | - Jiyoung Moon
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Soo Jeong Lee
- Department of Chemistry, Yeungnam University, Gyeongsan 38541, Republic of Korea
| | - Seong Yeon Park
- Department of Chemistry, Yeungnam University, Gyeongsan 38541, Republic of Korea
| | - Seog Joon Yoon
- Department of Chemistry, Yeungnam University, Gyeongsan 38541, Republic of Korea
| | - JaeHong Park
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea
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2
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Wang Q, Zhu H, Tan Y, Hao J, Ye T, Tang H, Wang Z, Ma J, Sun J, Zhang T, Zheng F, Zhang W, Choi HW, Choy WCH, Wu D, Sun XW, Wang K. Spin Quantum Dot Light-Emitting Diodes Enabled by 2D Chiral Perovskite with Spin-Dependent Carrier Transport. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2305604. [PMID: 37789724 DOI: 10.1002/adma.202305604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 10/02/2023] [Indexed: 10/05/2023]
Abstract
Chiral-induced spin selectivity (CISS) effect provides innovative approach to spintronics and quantum-based devices for chiral materials. Different from the conventional ferromagnetic devices, the application of CISS effect is potential to operate under room temperature and zero applied magnetic field. Low dimensional chiral perovskites by introducing chiral amines are beginning to show significant CISS effect for spin injection, but research on chiral perovskites is still in its infancy, especially on spin-light emitting diode (spin-LED) construction. Here, the spin-QLEDs enabled by 2D chiral perovskites as CISS layer for spin-dependent carrier injection and CdSe/ZnS quantum dots (QDs) as light emitting layer are reported. The regulation pattern of the chirality and thickness of chiral perovskites, which affects the circularly polarized electroluminescence (CP-EL) emission of spin-QLED, is discovered. Notably, the spin injection polarization of 2D chiral perovskites is higher than 80% and the CP-EL asymmetric factor (gCP-EL ) achieves up to 1.6 × 10-2 . Consequently, this work opens up a new and effective approach for high-performance spin-LEDs.
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Affiliation(s)
- Qingqian Wang
- Institute of Nanoscience and Applications, Department of Electronic and Electrical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
- Institute of Physics, Henan Academy of Sciences, Zhengzhou, 450046, China
| | - Hongmei Zhu
- Institute of Nanoscience and Applications, Department of Electronic and Electrical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Yangzhi Tan
- Institute of Nanoscience and Applications, Department of Electronic and Electrical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, 999077, China
| | - Junjie Hao
- Institute of Nanoscience and Applications, Department of Electronic and Electrical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
- College of Integrated Circuits and Optoelectronic Chips, Shenzhen Technology University, Shenzhen, 518118, China
| | - Taikang Ye
- Institute of Nanoscience and Applications, Department of Electronic and Electrical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Haodong Tang
- Institute of Nanoscience and Applications, Department of Electronic and Electrical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
- College of Integrated Circuits and Optoelectronic Chips, Shenzhen Technology University, Shenzhen, 518118, China
| | - Zhaojin Wang
- Institute of Nanoscience and Applications, Department of Electronic and Electrical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Jingrui Ma
- Institute of Nanoscience and Applications, Department of Electronic and Electrical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Jiayun Sun
- Institute of Nanoscience and Applications, Department of Electronic and Electrical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, 999077, China
| | - Tianqi Zhang
- Institute of Nanoscience and Applications, Department of Electronic and Electrical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Fankai Zheng
- Institute of Nanoscience and Applications, Department of Electronic and Electrical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Wenda Zhang
- Institute of Nanoscience and Applications, Department of Electronic and Electrical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Hoi Wai Choi
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, 999077, China
| | - Wallace C H Choy
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, 999077, China
| | - Dan Wu
- College of New Materials and New Energies, Shenzhen Technology University, Shenzhen, 518118, China
| | - Xiao Wei Sun
- Institute of Nanoscience and Applications, Department of Electronic and Electrical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Kai Wang
- Institute of Nanoscience and Applications, Department of Electronic and Electrical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
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3
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Nugraha MI, Indriyati I, Primadona I, Gedda M, Timuda GE, Iskandar F, Anthopoulos TD. Recent Progress in Colloidal Quantum Dot Thermoelectrics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2210683. [PMID: 36857683 DOI: 10.1002/adma.202210683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 02/12/2023] [Indexed: 06/18/2023]
Abstract
Semiconducting colloidal quantum dots (CQDs) represent an emerging class of thermoelectric materials for use in a wide range of future applications. CQDs combine solution processability at low temperatures with the potential for upscalable manufacturing via printing techniques. Moreover, due to their low dimensionality, CQDs exhibit quantum confinement and a high density of grain boundaries, which can be independently exploited to tune the Seebeck coefficient and thermal conductivity, respectively. This unique combination of attractive attributes makes CQDs very promising for application in emerging thermoelectric generator (TEG) technologies operating near room temperature. Herein, recent progress in CQDs for application in emerging thin-film thermoelectrics is reviewed. First, the fundamental concepts of thermoelectricity in nanostructured materials are outlined, followed by an overview of the popular synthetic methods used to produce CQDs with controllable sizes and shapes. Recent strides in CQD-based thermoelectrics are then discussed with emphasis on their application in thin-film TEGs. Finally, the current challenges and future perspectives for further enhancing the performance of CQD-based thermoelectric materials for future applications are discussed.
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Affiliation(s)
- Mohamad Insan Nugraha
- Physical Science and Engineering Division (PSE), KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
- Research Center for Advanced Materials, National Research and Innovation Agency (BRIN), South Tangerang, Banten, 15314, Indonesia
| | - Indriyati Indriyati
- Research Center for Advanced Materials, National Research and Innovation Agency (BRIN), South Tangerang, Banten, 15314, Indonesia
- Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, 40132, Indonesia
| | - Indah Primadona
- Research Center for Advanced Materials, National Research and Innovation Agency (BRIN), South Tangerang, Banten, 15314, Indonesia
- Collaboration Research Center for Advanced Energy Materials, National Research and Innovation Agency - Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, 40135, Indonesia
| | - Murali Gedda
- Physical Science and Engineering Division (PSE), KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Gerald Ensang Timuda
- Research Center for Advanced Materials, National Research and Innovation Agency (BRIN), South Tangerang, Banten, 15314, Indonesia
| | - Ferry Iskandar
- Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, 40132, Indonesia
- Collaboration Research Center for Advanced Energy Materials, National Research and Innovation Agency - Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, 40135, Indonesia
| | - Thomas D Anthopoulos
- Physical Science and Engineering Division (PSE), KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
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4
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Keating LP, Lee H, Rogers SP, Huang C, Shim M. Charging and Charged Species in Quantum Dot Light-Emitting Diodes. NANO LETTERS 2022; 22:9500-9506. [PMID: 36459088 DOI: 10.1021/acs.nanolett.2c03564] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Despite recent rapid advances in improving quantum dot light-emitting diodes, many fundamental aspects of the device operating mechanism remain unresolved. Through transient electroluminescence and time-resolved photoluminescence measurements, the effects of offset voltage on charging and charge transport are examined. First, capacitive charging occurs with a time constant of ∼500 ns, followed by electron transport through quantum dots with a mobility of ∼10-5 cm2 V-1 s-1. Hole injection then initiates an electroluminescence rise that is independent of offset voltage. The photoluminescence lifetime is also unaffected by the offset voltage, indicating no injection of charges into the quantum dots or on their surfaces prior to the voltage pulse. A slower equilibration to steady-state electroluminescence is dependent on the offset voltage, indicative of another charging process. Elemental mapping shows that ZnO deposition from solution can lead to the diffusion of charged species into the quantum dot layer, which may cause the slower process.
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Affiliation(s)
- Logan P Keating
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States
| | - Hyunho Lee
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States
| | - Steven P Rogers
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States
| | - Conan Huang
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States
| | - Moonsub Shim
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States
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5
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Brett MW, Gordon CK, Hardy J, Davis NJLK. The Rise and Future of Discrete Organic-Inorganic Hybrid Nanomaterials. ACS PHYSICAL CHEMISTRY AU 2022; 2:364-387. [PMID: 36855686 PMCID: PMC9955269 DOI: 10.1021/acsphyschemau.2c00018] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Hybrid nanomaterials (HNs), the combination of organic semiconductor ligands attached to nanocrystal semiconductor quantum dots, have applications that span a range of practical fields, including biology, chemistry, medical imaging, and optoelectronics. Specifically, HNs operate as discrete, tunable systems that can perform prompt fluorescence, energy transfer, singlet fission, upconversion, and/or thermally activated delayed fluorescence. Interest in HNs has naturally grown over the years due to their tunability and broad spectrum of applications. This Review presents a brief introduction to the components of HNs, before expanding on the characterization and applications of HNs. Finally, the future of HN applications is discussed.
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6
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Maier A, Strauß F, Kohlschreiber P, Schedel C, Braun K, Scheele M. Sub-nanosecond Intrinsic Response Time of PbS Nanocrystal IR-Photodetectors. NANO LETTERS 2022; 22:2809-2816. [PMID: 35311295 DOI: 10.1021/acs.nanolett.1c04938] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Colloidal nanocrystals (NCs), especially lead sulfide NCs, are promising candidates for solution-processed next-generation photodetectors with high-speed operation frequencies. However, the intrinsic response time of PbS-NC photodetectors, which is the material-specific physical limit, is still elusive, as the reported response times are typically limited by the device geometry. Here, we use the two-pulse coincidence photoresponse technique to identify the intrinsic response time of 1,2-ethanedithiol-functionalized PbS-NC photodetectors after femtosecond-pulsed 1560 nm excitation. We obtain an intrinsic response time of ∼1 ns, indicating an intrinsic bandwidth of ∼0.55 GHz as the material-specific limit. Examination of the dependence on laser power, gating, bias, temperature, channel length, and environmental conditions suggest that Auger recombination, assisted by NC-surface defects, is the dominant mechanism. Accordingly, the intrinsic response time might further be tuned by specifically controlling the ligand coverage and trap states. Thus, PbS-NC photodetectors are feasible for gigahertz optical communication in the third telecommunication window.
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Affiliation(s)
- Andre Maier
- Institute of Physical and Theoretical Chemistry, Universität Tübingen, Auf der Morgenstelle 18, D-72076Tübingen, Germany
- Center for Light-Matter Interaction, Sensors and Analytics LISA+, Universität Tübingen, Auf der Morgenstelle 15, D-72076 Tübingen, Germany
| | - Fabian Strauß
- Institute of Physical and Theoretical Chemistry, Universität Tübingen, Auf der Morgenstelle 18, D-72076Tübingen, Germany
- Center for Light-Matter Interaction, Sensors and Analytics LISA+, Universität Tübingen, Auf der Morgenstelle 15, D-72076 Tübingen, Germany
| | - Pia Kohlschreiber
- Institute of Physical and Theoretical Chemistry, Universität Tübingen, Auf der Morgenstelle 18, D-72076Tübingen, Germany
- Center for Light-Matter Interaction, Sensors and Analytics LISA+, Universität Tübingen, Auf der Morgenstelle 15, D-72076 Tübingen, Germany
| | - Christine Schedel
- Institute of Physical and Theoretical Chemistry, Universität Tübingen, Auf der Morgenstelle 18, D-72076Tübingen, Germany
| | - Kai Braun
- Institute of Physical and Theoretical Chemistry, Universität Tübingen, Auf der Morgenstelle 18, D-72076Tübingen, Germany
- Center for Light-Matter Interaction, Sensors and Analytics LISA+, Universität Tübingen, Auf der Morgenstelle 15, D-72076 Tübingen, Germany
| | - Marcus Scheele
- Institute of Physical and Theoretical Chemistry, Universität Tübingen, Auf der Morgenstelle 18, D-72076Tübingen, Germany
- Center for Light-Matter Interaction, Sensors and Analytics LISA+, Universität Tübingen, Auf der Morgenstelle 15, D-72076 Tübingen, Germany
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7
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Zhang J, Zhang L, Zhang Q. Element doping-induced effects in Zn-doped CdTe quantum-dot system: Insights from an ultrafast dynamics perspective. J Chem Phys 2022; 156:034701. [DOI: 10.1063/5.0078477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Jiachen Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Lei Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Qun Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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8
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Development of QDs-based nanosensors for heavy metal detection: A review on transducer principles and in-situ detection. Talanta 2021; 239:122903. [PMID: 34857381 DOI: 10.1016/j.talanta.2021.122903] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 09/15/2021] [Accepted: 09/22/2021] [Indexed: 12/17/2022]
Abstract
Heavy metal pollution has severe threats to the ecological environment and human health. Thus, it is urgent to achieve the rapid, selective, sensitive and portable detection of heavy metal ions. To overcome the defects of traditional methods such as time-consuming, low sensitivity, high cost and complicated operation, QDs (Quantum dots)-based nanomaterials have been used in sensors to significantly improve the sensing performance. Due to their excellent physicochemical properties, high specific surface area, high adsorption and reactive capacity, nanomaterials could act as potential probes or offer enhanced sensitivity and create a promising nanosensors platform. In this review, the rapidly advancing types of QDs for heavy metal ions detection are first summarized. Modified with ligands, nanomaterials, or biomaterials, QDs are assembled on sensors by the interaction of electrostatic adsorption, chemical bonding, steric hindrance, and base-pairing. The stability of QDs-based nanosensors is improved by doping the elements to QDs, providing the reference substance, optimizing the assemble strategies and so on. Then, according to transducer principles, the two most typical sensor categories based on QDs: optical and electrochemical sensors are highlighted to be discussed. In the meanwhile, portable devices combining with QDs to adapt the practical detection in complex situations are summarized. The deficiencies and future challenges of QDs in toxicity, specificity, portability, multi-metal co-detection and degradation during the detection are also pointed out. In the end, the development trends of QDs-based nanosensors for heavy metal ions detection are discussed. This review presents an overall understanding, recent advances, current challenges and future outlook of QDs-based nanosensors for heavy metal detection.
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9
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Bashir R, Bilal MK, Bashir A, Zhao J, Asif SU, Ahmad W, Xie J, Hu W. A low-temperature solution-processed indium incorporated zinc oxide electron transport layer for high-efficiency lead sulfide colloidal quantum dot solar cells. NANOSCALE 2021; 13:12991-12999. [PMID: 34477782 DOI: 10.1039/d1nr03572j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Colloidal quantum dot solar cells (CQDSCs) have achieved remarkable progress recently in terms of mainly surface passivation and composition-matching matrices on CQDs, while improving the overall photoelectric conversion efficiency (PCE) through electron transport layer (ETL) modifications is less explored. We report a low-temperature solution route to synthesize donor (Al3+/Ga3+/In3+) incorporated zinc oxide (AZO/GZO/IZO) ETL films for PbS CQDSCs. Spectroscopic characterization studies indicate that the IZO ETL fabricated with 150 °C annealing can increase the bandgap the most from 3.56 eV to 3.74 eV, possesses enhanced light transmission (∼94%) and finer particle sizes, and importantly shows the most suitable band alignment and charge transfer ability. Well-dispersed PbS CQDs of around 3 nm are synthesized by a N2-protected reflux method and are surface exchanged with 1-ethyl-3-methylimidazolium iodide (EMII) to allow I- grafting and ethanedithiol (EDT) for the active layer and hole transport layer, respectively. The IZO based PbS CQDSC, with a device architecture of ITO/IZO/PbS-EMII/PbS-EDT/Au, shows an enhanced PCE of 11.1% (comparatively 18% higher than that of the ZnO ETL), a VOC value of 0.64 V, and a JSC of 25.8 mA cm-2. The improved performances benefit from the higher recombination resistance and constrained photoluminescence emission with the utilization of the IZO ETL that provides a superior charge transfer property.
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Affiliation(s)
- Rabia Bashir
- Key Laboratory of LCR Materials and Devices of Yunnan Province, National Center for International Research on Photoelectric and Energy Materials, School of Materials and Energy, Yunnan University, Kunming 650091, P. R. China.
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10
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Carulli F, Pinchetti V, Zaffalon ML, Camellini A, Rotta Loria S, Moro F, Fanciulli M, Zavelani-Rossi M, Meinardi F, Crooker SA, Brovelli S. Optical and Magneto-Optical Properties of Donor-Bound Excitons in Vacancy-Engineered Colloidal Nanocrystals. NANO LETTERS 2021; 21:6211-6219. [PMID: 34260252 PMCID: PMC8397387 DOI: 10.1021/acs.nanolett.1c01818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/30/2021] [Indexed: 06/13/2023]
Abstract
Controlled insertion of electronic states within the band gap of semiconductor nanocrystals (NCs) is a powerful tool for tuning their physical properties. One compelling example is II-VI NCs incorporating heterovalent coinage metals in which hole capture produces acceptor-bound excitons. To date, the opposite donor-bound exciton scheme has not been realized because of the unavailability of suitable donor dopants. Here, we produce a model system for donor-bound excitons in CdSeS NCs engineered with sulfur vacancies (VS) that introduce a donor state below the conduction band (CB), resulting in long-lived intragap luminescence. VS-localized electrons are almost unaffected by trapping, and suppression of thermal quenching boosts the emission efficiency to 85%. Magneto-optical measurements indicate that the VS are not magnetically coupled to the NC bands and that the polarization properties are determined by the spin of the valence-band photohole, whose spin flip is massively slowed down due to suppressed exchange interaction with the donor-localized electron.
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Affiliation(s)
- Francesco Carulli
- Dipartimento
di Scienza dei Materiali, Università
degli Studi di Milano-Bicocca, via Cozzi 55, IT-20125 Milano, Italy
| | - Valerio Pinchetti
- Dipartimento
di Scienza dei Materiali, Università
degli Studi di Milano-Bicocca, via Cozzi 55, IT-20125 Milano, Italy
| | - Matteo L. Zaffalon
- Dipartimento
di Scienza dei Materiali, Università
degli Studi di Milano-Bicocca, via Cozzi 55, IT-20125 Milano, Italy
| | - Andrea Camellini
- Dipartimento
di Energia, Politecnico di Milano, IT-20133 Milano, Italy
| | | | - Fabrizio Moro
- Dipartimento
di Scienza dei Materiali, Università
degli Studi di Milano-Bicocca, via Cozzi 55, IT-20125 Milano, Italy
| | - Marco Fanciulli
- Dipartimento
di Scienza dei Materiali, Università
degli Studi di Milano-Bicocca, via Cozzi 55, IT-20125 Milano, Italy
| | | | - Francesco Meinardi
- Dipartimento
di Scienza dei Materiali, Università
degli Studi di Milano-Bicocca, via Cozzi 55, IT-20125 Milano, Italy
| | - Scott A. Crooker
- National
High Magnetic Field Laboratory, Los Alamos
National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Sergio Brovelli
- Dipartimento
di Scienza dei Materiali, Università
degli Studi di Milano-Bicocca, via Cozzi 55, IT-20125 Milano, Italy
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11
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Zhao Q, Gouget G, Guo J, Yang S, Zhao T, Straus DB, Qian C, Oh N, Wang H, Murray CB, Kagan CR. Enhanced Carrier Transport in Strongly Coupled, Epitaxially Fused CdSe Nanocrystal Solids. NANO LETTERS 2021; 21:3318-3324. [PMID: 33792310 DOI: 10.1021/acs.nanolett.1c00860] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Strongly coupled, epitaxially fused colloidal nanocrystal (NC) solids are promising solution-processable semiconductors to realize optoelectronic devices with high carrier mobilities. Here, we demonstrate sequential, solid-state cation exchange reactions to transform epitaxially connected PbSe NC thin films into Cu2Se nanostructured thin-film intermediates and then successfully to achieve zinc-blende, CdSe NC solids with wide epitaxial necking along {100} facets. Transient photoconductivity measurements probe carrier transport at nanometer length scales and show a photoconductance of 0.28(1) cm2 V-1 s-1, the highest among CdSe NC solids reported. Atomic-layer deposition of a thin Al2O3 layer infiltrates and protects the structure from fusing into a polycrystalline thin film during annealing and further improves the photoconductance to 1.71(5) cm2 V-1 s-1 and the diffusion length to 760 nm. We fabricate field-effect transistors to study carrier transport at micron length scales and realize high electron mobilities of 35(3) cm2 V-1 s-1 with on-off ratios of 106 after doping.
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12
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Abstract
LEDs achieved success in creating a mesmerizing life for humans. LEDs with low output are relatively cheap, and hence, they are used for many temporary purposes such as glow sticks, photonic textiles, and LED art by artists. Besides the basic applications, LEDs have made strong strides in several new fields of applications and emerged as leaders in the technological growth. The LED industry has experienced tremendous change since its inception in the commercial market. In over a decade, the LED efficiencies have improved and their cost has lowered down. This has created numerous growth opportunities to implement LEDs for multiple businesses and newer products.
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13
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Xia P, Davies DW, Patel BB, Qin M, Liang Z, Graham KR, Diao Y, Tang ML. Spin-coated fluorinated PbS QD superlattice thin film with high hole mobility. NANOSCALE 2020; 12:11174-11181. [PMID: 32406467 DOI: 10.1039/d0nr02299c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Motivated by the oleophobic and electron-withdrawing nature of perfluorocarbons, we explore the effect of a trifluoromethyl coating on lead sulfide quantum dots (PbS QDs) in thin film transistor (TFT) geometry. The low surface energy conferred by the oleophobic perfluorocarbons creates QDs packed in a primitive cubic lattice with long range order, as confirmed by grazing incidence small angle X-ray scattering (GISAXS) and transmission electron microscopy (TEM). Hole mobilities as high as 0.085 cm2 V-1 s-1 were measured in the TFTs. No electron transport was observed. This suggests that the electron-withdrawing nature of the trifluoromethyl ligand is eclipsed by the excess holes present in the PbS QDs that likely stem from cation vacancies induced by the thiol group.
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Affiliation(s)
- Pan Xia
- Department of Chemistry & Materials Science and Engineering Program, University of California, Riverside, 900 University Avenue, Riverside, California 92521, USA.
| | - Daniel W Davies
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Bijal B Patel
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Maotong Qin
- Department of Materials Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, NO. 96 Jinzhai Road, Hefei, Anhui, 230026 P. R. China
| | - Zhiming Liang
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Kenneth R Graham
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Ying Diao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Ming Lee Tang
- Department of Chemistry & Materials Science and Engineering Program, University of California, Riverside, 900 University Avenue, Riverside, California 92521, USA.
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14
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Sliz R, Lejay M, Fan JZ, Choi MJ, Kinge S, Hoogland S, Fabritius T, García de Arquer FP, Sargent EH. Stable Colloidal Quantum Dot Inks Enable Inkjet-Printed High-Sensitivity Infrared Photodetectors. ACS NANO 2019; 13:11988-11995. [PMID: 31545597 DOI: 10.1021/acsnano.9b06125] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Colloidal quantum dots (CQDs) have recently gained attention as materials for manufacturing optoelectronic devices in view of their tunable light absorption and emission properties and compatibility with low-temperature thin-film manufacture. The realization of CQD inkjet-printed infrared photodetectors has thus far been hindered by incompatibility between the chemical processes that produce state-of-the-art CQD solution-exchanged inks and the requirements of ink formulations for inkjet materials processing. To achieve inkjet-printed CQD solids with a high degree of reproducibility, as well as with the needed morphological and optoelectronic characteristics, we sought to overcome the mismatch among these processing conditions. In this study, we design CQD inks by simultaneous evaluation of requirements regarding ink colloidal stability, jetting conditions, and film morphology for different dots and solvents. The new inks remain colloidally stable, achieved through a design that suppresses the reductant properties of amines on the dots' surface. After drop ejection from the nozzle, the quantum dot material is immobilized on the substrate surface due to the rapid evaporation of the low boiling point amine-based compound. Concurrently, the high boiling point solvent allows for the formation of a thin film of high uniformity, as is required for the fabrication of high-performance IR photodetectors. We fabricate inkjet-printed photodetectors exhibiting the highest specific detectivities reported to date (above 1012 Jones across the IR) in an inkjet-printed quantum dot film. As a patternable CMOS-compatible process, the work offers routes to integrated sensing devices and systems.
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Affiliation(s)
- Rafal Sliz
- Department of Electrical and Computing Engineering , University of Toronto , 10 King's College Road , Toronto , Ontario M5S 3G4 , Canada
- Optoelectronics and Measurement Techniques Unit , University of Oulu , 90570 Oulu , Finland
| | - Marc Lejay
- Department of Electrical and Computing Engineering , University of Toronto , 10 King's College Road , Toronto , Ontario M5S 3G4 , Canada
| | - James Z Fan
- Department of Electrical and Computing Engineering , University of Toronto , 10 King's College Road , Toronto , Ontario M5S 3G4 , Canada
| | - Min-Jae Choi
- Department of Electrical and Computing Engineering , University of Toronto , 10 King's College Road , Toronto , Ontario M5S 3G4 , Canada
| | - Sachin Kinge
- Advanced Technology Div. , Hoge Wei 33 , Toyota Technical Centre, B-1930 Zaventem , Belgium
| | - Sjoerd Hoogland
- Department of Electrical and Computing Engineering , University of Toronto , 10 King's College Road , Toronto , Ontario M5S 3G4 , Canada
| | - Tapio Fabritius
- Optoelectronics and Measurement Techniques Unit , University of Oulu , 90570 Oulu , Finland
| | - F Pelayo García de Arquer
- Department of Electrical and Computing Engineering , University of Toronto , 10 King's College Road , Toronto , Ontario M5S 3G4 , Canada
| | - Edward H Sargent
- Department of Electrical and Computing Engineering , University of Toronto , 10 King's College Road , Toronto , Ontario M5S 3G4 , Canada
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15
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Wang H, Butler DJ, Straus DB, Oh N, Wu F, Guo J, Xue K, Lee JD, Murray CB, Kagan CR. Air-Stable CuInSe 2 Nanocrystal Transistors and Circuits via Post-Deposition Cation Exchange. ACS NANO 2019; 13:2324-2333. [PMID: 30707549 DOI: 10.1021/acsnano.8b09055] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Colloidal semiconductor nanocrystals (NCs) are a promising materials class for solution-processable, next-generation electronic devices. However, most high-performance devices and circuits have been achieved using NCs containing toxic elements, which may limit their further device development. We fabricate high mobility CuInSe2 NC field-effect transistors (FETs) using a solution-based, post-deposition, sequential cation exchange process that starts with electronically coupled, thiocyanate (SCN)-capped CdSe NC thin films. First Cu+ is substituted for Cd2+ transforming CdSe NCs to Cu-rich Cu2Se NC films. Next, Cu2Se NC films are dipped into a Na2Se solution to Se-enrich the NCs, thus compensating the Cu-rich surface, promoting fusion of the Cu2Se NCs, and providing sites for subsequent In-dopants. The liquid-coordination-complex trioctylphosphine-indium chloride (TOP-InCl3) is used as a source of In3+ to partially exchange and n-dope CuInSe2 NC films. We demonstrate Al2O3-encapsulated, air-stable CuInSe2 NC FETs with linear (saturation) electron mobilities of 8.2 ± 1.8 cm2/(V s) (10.5 ± 2.4 cm2/(V s)) and with current modulation of 105, comparable to that for high-performance Cd-, Pb-, and As-based NC FETs. The CuInSe2 NC FETs are used as building blocks of integrated inverters to demonstrate their promise for low-cost, low-toxicity NC circuits.
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Affiliation(s)
| | | | | | - Nuri Oh
- Division of Materials Science and Engineering , Hanyang University , Seoul 133-791 , Republic of Korea
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16
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Righetto M, Privitera A, Carraro F, Bolzonello L, Ferrante C, Franco L, Bozio R. Engineering interactions in QDs-PCBM blends: a surface chemistry approach. NANOSCALE 2018; 10:11913-11922. [PMID: 29901055 DOI: 10.1039/c8nr03520b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Here we present a comprehensive study on the photophysics of QDs-fullerene blends, aiming to elucidate the impact of ligands on the extraction of carriers from QDs. We investigated how three different ligands (oleylamine, octadecanethiol and propanethiol) influence the dynamics of charge generation, separation, and recombination in blends of CdSe/CdS core/shell QDs and PCBM. We accessed each relevant process directly by combining the results from both optical and magnetic spectroscopies. Transient absorption measurements revealed a faster interaction dynamics in thiol-capped ligands. Through phenomenological modeling of the interaction processes, i.e., energy transfer and electron transfer, we estimated the suppression of exciton migration and the enhancement of electron transfer processes when alkyl-thiols are employed as ligands. Contextually, we report the profound impact of the ligands' alkyl chain length, leading to strengthened interactions with PCBM acceptors. Quantitatively, we measured a 10-fold increase in the electron transfer rate when oleylamine ligands were exchanged with propanethiol ligands. EPR spectroscopy gave access to subtle details regarding both the enhanced charge generation and lower binding energy of charge-transfer states in blends compared to PCBM alone. Moreover, through pulsed EPR techniques, we inferred the localization of deep electron traps in localized sites close to QDs in the blends. Therefore, our thorough characterization evidenced the essential role of ligands in determining QD interactions. We believe that these discoveries will contribute to the efficient incorporation of QDs in existing organic PV technologies.
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Affiliation(s)
- Marcello Righetto
- Department of Chemical Science and U.R. INSTM, University of Padova, Via Marzolo 1, I-35131, Padova, Italy.
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17
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Azzaro MS, Dodin A, Zhang DY, Willard AP, Roberts ST. Exciton-Delocalizing Ligands Can Speed Up Energy Migration in Nanocrystal Solids. NANO LETTERS 2018; 18:3259-3270. [PMID: 29652509 DOI: 10.1021/acs.nanolett.8b01079] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Researchers have long sought to use surface ligands to enhance energy migration in nanocrystal solids by decreasing the physical separation between nanocrystals and strengthening their electronic coupling. Exciton-delocalizing ligands, which possess frontier molecular orbitals that strongly mix with nanocrystal band-edge states, are well-suited for this role because they can facilitate carrier-wave function extension beyond the nanocrystal core, reducing barriers for energy transfer. This report details the use of the exciton-delocalizing ligand phenyldithiocarbamate (PDTC) to tune the transport rate and diffusion length of excitons in CdSe nanocrystal solids. A film composed of oleate-terminated CdSe nanocrystals is subjected to a solid-state ligand exchange to replace oleate with PDTC. Exciton migration in the films is subsequently investigated by femtosecond transient absorption. Our experiments indicate that the treatment of nanocrystal films with PDTC leads to rapid (∼400 fs) downhill energy migration (∼80 meV), while no such migration occurs in oleate-capped films. Kinetic Monte Carlo simulations allow us to extract both rates and length scales for exciton diffusion in PDTC-treated films. These simulations reproduce dynamics observed in transient absorption measurements over a range of temperatures and confirm excitons hop via a Miller-Abrahams mechanism. Importantly, our experiments and simulations show PDTC treatment increases the exciton hopping rate to 200 fs, an improvement of 5 orders of magnitude relative to oleate-capped films. This exciton hopping rate stands as one of the fastest determined for CdSe solids. The facile, room-temperature processing and improved transport properties offered by the solid-state exchange of exciton-delocalizing ligands show they offer promise for the construction of strongly coupled nanocrystal arrays.
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Affiliation(s)
| | - Amro Dodin
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | | | - Adam P Willard
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
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18
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Jung SM, Kang HL, Won JK, Kim J, Hwang C, Ahn K, Chung I, Ju BK, Kim MG, Park SK. High-Performance Quantum Dot Thin-Film Transistors with Environmentally Benign Surface Functionalization and Robust Defect Passivation. ACS APPLIED MATERIALS & INTERFACES 2018; 10:3739-3749. [PMID: 29322770 DOI: 10.1021/acsami.7b13997] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The recent development of high-performance colloidal quantum dot (QD) thin-film transistors (TFTs) has been achieved with removal of surface ligand, defect passivation, and facile electronic doping. Here, we report on high-performance solution-processed CdSe QD-TFTs with an optimized surface functionalization and robust defect passivation via hydrazine-free metal chalcogenide (MCC) ligands. The underlying mechanism of the ligand effects on CdSe QDs has been studied with hydrazine-free ex situ reaction derived MCC ligands, such as Sn2S64-, Sn2Se64-, and In2Se42-, to allow benign solution-process available. Furthermore, the defect passivation and remote n-type doping effects have been investigated by incorporating indium nanoparticles over the QD layer. Strong electronic coupling and solid defect passivation of QDs could be achieved by introducing electronically active MCC capping and thermal diffusion of the indium nanoparticles, respectively. It is also noteworthy that the diffused indium nanoparticles facilitate charge injection not only inter-QDs but also between source/drain electrodes and the QD semiconductors, significantly reducing contact resistance. With benign organic solvents, the Sn2S64-, Sn2Se64-, and In2Se42- ligand based QD-TFTs exhibited field-effect mobilities exceeding 4.8, 12.0, and 44.2 cm2/(V s), respectively. The results reported here imply that the incorporation of MCC ligands and appropriate dopants provide a general route to high-performance, extremely stable solution-processed QD-based electronic devices with marginal toxicity, offering compatibility with standard complementary metal oxide semiconductor processing and large-scale on-chip device applications.
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Affiliation(s)
| | - Han Lim Kang
- School of Electrical and Electronic Engineering, Korea University , Seoul 02841, Republic of Korea
| | | | | | | | - KyungHan Ahn
- Center for Nanoparticle Research, Institute for Basic Science (IBS) , Daejeon 34126, Republic of Korea
| | - In Chung
- Center for Nanoparticle Research, Institute for Basic Science (IBS) , Daejeon 34126, Republic of Korea
- School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University , Seoul 08826, Republic of Korea
| | - Byeong-Kwon Ju
- School of Electrical and Electronic Engineering, Korea University , Seoul 02841, Republic of Korea
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19
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Chistyakov AA, Zvaigzne MA, Nikitenko VR, Tameev AR, Martynov IL, Prezhdo OV. Optoelectronic Properties of Semiconductor Quantum Dot Solids for Photovoltaic Applications. J Phys Chem Lett 2017; 8:4129-4139. [PMID: 28799772 DOI: 10.1021/acs.jpclett.7b00671] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Quantum dot (QD) solids represent a new type of condensed matter drawing high fundamental and applied interest. Quantum confinement in individual QDs, combined with macroscopic scale whole materials, leads to novel exciton and charge transfer features that are particularly relevant to optoelectronic applications. This Perspective discusses the structure of semiconductor QD solids, optical and spectral properties, charge carrier transport, and photovoltaic applications. The distance between adjacent nanoparticles and surface ligands influences greatly electrostatic interactions between QDs and, hence, charge and energy transfer. It is almost inevitable that QD solids exhibit energetic disorder that bears many similarities to disordered organic semiconductors, with charge and exciton transport described by the multiple trapping model. QD solids are synthesized at low cost from colloidal solutions by casting, spraying, and printing. A judicious selection of a layer sequence involving QDs with different size, composition, and ligands can be used to harvest sunlight over a wide spectral range, leading to inexpensive and efficient photovoltaic devices.
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Affiliation(s)
- A A Chistyakov
- National Research Nuclear University "MEPhI" (Moscow Engineering Physics Institute) , Moscow 115409, Russia
| | - M A Zvaigzne
- National Research Nuclear University "MEPhI" (Moscow Engineering Physics Institute) , Moscow 115409, Russia
| | - V R Nikitenko
- National Research Nuclear University "MEPhI" (Moscow Engineering Physics Institute) , Moscow 115409, Russia
| | - A R Tameev
- National Research Nuclear University "MEPhI" (Moscow Engineering Physics Institute) , Moscow 115409, Russia
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry of the Russian Academy of Sciences , 31-building 4 Leninsky Prospect, Moscow 119071, Russia
| | - I L Martynov
- National Research Nuclear University "MEPhI" (Moscow Engineering Physics Institute) , Moscow 115409, Russia
| | - O V Prezhdo
- National Research Nuclear University "MEPhI" (Moscow Engineering Physics Institute) , Moscow 115409, Russia
- Department of Chemistry, Department of Physics, and Department of Astronomy, University of Southern California , Los Angeles, California 90089, United States
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20
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Sayevich V, Guhrenz C, Dzhagan VM, Sin M, Werheid M, Cai B, Borchardt L, Widmer J, Zahn DRT, Brunner E, Lesnyak V, Gaponik N, Eychmüller A. Hybrid N-Butylamine-Based Ligands for Switching the Colloidal Solubility and Regimentation of Inorganic-Capped Nanocrystals. ACS NANO 2017; 11:1559-1571. [PMID: 28052188 DOI: 10.1021/acsnano.6b06996] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We report on a simple and effective technique of tuning the colloidal solubility of inorganic-capped CdSe and CdSe/CdS core/shell nanocrystals (NCs) from highly polar to nonpolar media using n-butylamine molecules. The introduction of the short and volatile organic amine mainly results in a modification of the labile diffusion region of the inorganic-capped NCs, enabling a significant extension of their dispersibility and improving the ability to form long-range assemblies. Moreover, the hybrid n-butylamine/inorganic capping can be thermally decomposed under mild heat treatment, making this approach of surface functionalization well-compatible with a low-temperature, solution-processed device fabrication. Particularly, a field-effect transistor-based on n-butylamine/Ga-I-complex-capped 4.5 nm CdSe NC solids shows excellent transport characteristics with electron mobilities up to 2 cm2/(V·s) and a high current modulation value (>104) at a low operation voltage (<2 V).
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Affiliation(s)
- Vladimir Sayevich
- Physical Chemistry and Center for Advancing Electronics Dresden (cfAED), TU Dresden , Bergstr. 66b, Dresden 01062, Germany
| | - Chris Guhrenz
- Physical Chemistry and Center for Advancing Electronics Dresden (cfAED), TU Dresden , Bergstr. 66b, Dresden 01062, Germany
| | | | - Maria Sin
- Department of Chemistry and Food Chemistry, Bioanalytical Chemistry, TU Dresden , Bergstr. 66, Dresden 01069, Germany
| | - Matthias Werheid
- Physical Chemistry and Center for Advancing Electronics Dresden (cfAED), TU Dresden , Bergstr. 66b, Dresden 01062, Germany
| | - Bin Cai
- Physical Chemistry and Center for Advancing Electronics Dresden (cfAED), TU Dresden , Bergstr. 66b, Dresden 01062, Germany
| | - Lars Borchardt
- Department of Inorganic Chemistry, TU Dresden , Bergstr. 66, Dresden 01062, Germany
| | - Johannes Widmer
- Institut für Angewandte Photophysik, TU Dresden , George-Bähr-Str. 1, Dresden 01069, Germany
| | | | - Eike Brunner
- Department of Chemistry and Food Chemistry, Bioanalytical Chemistry, TU Dresden , Bergstr. 66, Dresden 01069, Germany
| | - Vladimir Lesnyak
- Physical Chemistry and Center for Advancing Electronics Dresden (cfAED), TU Dresden , Bergstr. 66b, Dresden 01062, Germany
| | - Nikolai Gaponik
- Physical Chemistry and Center for Advancing Electronics Dresden (cfAED), TU Dresden , Bergstr. 66b, Dresden 01062, Germany
| | - Alexander Eychmüller
- Physical Chemistry and Center for Advancing Electronics Dresden (cfAED), TU Dresden , Bergstr. 66b, Dresden 01062, Germany
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21
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Oh SJ, Straus DB, Zhao T, Choi JH, Lee SW, Gaulding EA, Murray CB, Kagan CR. Engineering the surface chemistry of lead chalcogenide nanocrystal solids to enhance carrier mobility and lifetime in optoelectronic devices. Chem Commun (Camb) 2017; 53:728-731. [DOI: 10.1039/c6cc07916d] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We develop a hybrid ligand exchange process to enhance both mobility and lifetime of carriers in nanocrystal thin films.
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Affiliation(s)
- S. J. Oh
- Department of Materials Science and Engineering
- University of Pennsylvania
- Philadelphia
- USA
- Department of Materials Science and Engineering
| | - D. B. Straus
- Department of Chemistry
- University of Pennsylvania
- Philadelphia
- USA
| | - T. Zhao
- Department of Materials Science and Engineering
- University of Pennsylvania
- Philadelphia
- USA
| | - J.-H. Choi
- Department of Electrical and System Engineering
- University of Pennsylvania
- Philadelphia
- USA
- Rare Metals Research Center
| | - S.-W. Lee
- Department of Semiconductor System Engineering
- Korea University
- Seoul 02841
- Republic of Korea
| | - E. A. Gaulding
- Department of Materials Science and Engineering
- University of Pennsylvania
- Philadelphia
- USA
| | - C. B. Murray
- Department of Materials Science and Engineering
- University of Pennsylvania
- Philadelphia
- USA
- Department of Chemistry
| | - C. R. Kagan
- Department of Materials Science and Engineering
- University of Pennsylvania
- Philadelphia
- USA
- Department of Chemistry
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22
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Reich KV, Shklovskii BI. Exciton Transfer in Array of Epitaxially Connected Nanocrystals. ACS NANO 2016; 10:10267-10274. [PMID: 27805356 DOI: 10.1021/acsnano.6b05846] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Recently, epitaxially connected at facets semiconductor nanocrystals (NCs) have been introduced to fascilitate the electron transport between nanocrystals. To fully deploy their potential, a better understanding of the exciton transfer between connected NCs is needed. We go beyond the two well-known transfer mechanisms suggested by Förster and Dexter and propose a third mechanism of exciton tandem tunneling. The tandem tunneling occurs through the intermediate state in which the electron and hole are in different NCs. The corresponding rate for exciton hops is larger than the Dexter rate and for Si is even much larger that the Förster one.
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Affiliation(s)
- Konstantin V Reich
- Fine Theoretical Physics Institute, University of Minnesota , Minneapolis, Minnesota 55455, United States
- Ioffe Institute , St. Petersburg, 194021, Russia
| | - Boris I Shklovskii
- Fine Theoretical Physics Institute, University of Minnesota , Minneapolis, Minnesota 55455, United States
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23
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Zhao T, Goodwin ED, Guo J, Wang H, Diroll BT, Murray CB, Kagan CR. Advanced Architecture for Colloidal PbS Quantum Dot Solar Cells Exploiting a CdSe Quantum Dot Buffer Layer. ACS NANO 2016; 10:9267-9273. [PMID: 27649044 DOI: 10.1021/acsnano.6b03175] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Advanced architectures are required to further improve the performance of colloidal PbS heterojunction quantum dot solar cells. Here, we introduce a CdI2-treated CdSe quantum dot buffer layer at the junction between ZnO nanoparticles and PbS quantum dots in the solar cells. We exploit the surface- and size-tunable electronic properties of the CdSe quantum dots to optimize its carrier concentration and energy band alignment in the heterojunction. We combine optical, electrical, and analytical measurements to show that the CdSe quantum dot buffer layer suppresses interface recombination and contributes additional photogenerated carriers, increasing the open-circuit voltage and short-circuit current of PbS quantum dot solar cells, leading to a 25% increase in solar power conversion efficiency.
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Affiliation(s)
- Tianshuo Zhao
- Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical and Systems Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Earl D Goodwin
- Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical and Systems Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Jiacen Guo
- Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical and Systems Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Han Wang
- Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical and Systems Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Benjamin T Diroll
- Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical and Systems Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Christopher B Murray
- Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical and Systems Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Cherie R Kagan
- Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical and Systems Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
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24
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Affiliation(s)
- Simanta Kundu
- Department
of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Amitava Patra
- Department
of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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25
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Yoon SJ, Guo Z, Dos Santos Claro PC, Shevchenko EV, Huang L. Direct Imaging of Long-Range Exciton Transport in Quantum Dot Superlattices by Ultrafast Microscopy. ACS NANO 2016; 10:7208-7215. [PMID: 27387010 DOI: 10.1021/acsnano.6b03700] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Long-range charge and exciton transport in quantum dot (QD) solids is a crucial challenge in utilizing QDs for optoelectronic applications. Here, we present a direct visualization of exciton diffusion in highly ordered CdSe QDs superlattices by mapping exciton population using ultrafast transient absorption microscopy. A temporal resolution of ∼200 fs and a spatial precision of ∼50 nm of this technique provide a direct assessment of the upper limit for exciton transport in QD solids. An exciton diffusion length of ∼125 nm has been visualized in the 3 ns experimental time window and an exciton diffusion coefficient of (2.5 ± 0.2) × 10(-2) cm(2) s(-1) has been measured for superlattices constructed from 3.6 nm CdSe QDs with center-to-center distance of 6.7 nm. The measured exciton diffusion constant is in good agreement with Förster resonance energy transfer theory. We have found that exciton diffusion is greatly enhanced in the superlattices over the disordered films with an order of magnitude higher diffusion coefficient, pointing toward the role of disorder in limiting transport. This study provides important understandings on energy transport mechanisms in both the spatial and temporal domains in QD solids.
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Affiliation(s)
- Seog Joon Yoon
- Radiation Laboratory, University of Notre Dame , Notre Dame, Indiana 46556, United States
- Department of Chemistry and Biochemistry, University of Notre Dame , Notre Dame, Indiana 46556, United States
| | - Zhi Guo
- Department of Chemistry, Purdue University , West Lafayette, Indiana 47907, United States
| | - Paula C Dos Santos Claro
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Elena V Shevchenko
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Libai Huang
- Department of Chemistry, Purdue University , West Lafayette, Indiana 47907, United States
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