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Kambhampati P. Unraveling the excitonics of light emission from metal-halide perovskite quantum dots. NANOSCALE 2024; 16:15033-15058. [PMID: 39052235 DOI: 10.1039/d4nr01481b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
Metal halide semicondictor perovskites have been under intense investigation for their promise in light absorptive applications like photovoltaics. They have more recently experienced interest for their promise in light emissive applications. A key aspect of perovskites is their glassy, ionic lattice that exhibits dynamical disorder. One possible result of this dynamical disorder is their strong coupling between electronic and lattice degrees of freedom which may confer remarkable properties for light emission such as defect tolerance. How does the system, comprised of excitons, couple to the bath, comprised of lattice modes? How does this system-bath interaction give rise to novel light emissive properties and how do these properties give insight into the nature of these materials? We review recent work from this group in which time-resolved photoluminescence spectroscopy is used to reveal such insights. Based upon a fast time resolution of 3 ps, energy resolution, and temperature dependence, a wide variety of insights are gleaned. These insights include: lattice contributions to the emission linewidths, multiexciton formation, hot carrier cooling, excitonic fine structure, single dot superradiance, and a breakdown of the Condon approximation, all due to complex structural dynamics in these materials.
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2
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Rana G, Das S, Singha PK, Ali F, Maji R, Datta A. The effect of Cu(I)-doping on the photoinduced electron transfer from aqueous CdS quantum dots. J Chem Phys 2024; 161:024705. [PMID: 38990118 DOI: 10.1063/5.0218548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2024] [Accepted: 06/24/2024] [Indexed: 07/12/2024] Open
Abstract
The doping of CdS quantum dots (QDs) with Cu(I) disrupts electron-hole correlation due to hole trapping by the dopant ion, post-photoexcitation. The present paper examines the effect of such disruption on the rate of photoinduced electron transfer (PET) from the QDs to methyl viologen (MV2+), with implications in their photocatalytic activity. A significantly greater efficiency of PL quenching by MV2+ is observed for the doped QDs than for the undoped ones. Interestingly, the Stern-Volmer plots constructed using PL intensities exhibit an upward curvature for both the cases, while the PL lifetimes remain unaffected. This observation is rationalized by considering the adsorption of the quencher on the surface of the QDs and ultrafast PET post-photoexcitation. Ultrafast transient absorption experiments confirm a faster electron transfer for the doped QDs. It is also realized that the transient absorption experiment yields a more accurate estimate of the binding constant of the quencher with the QDs, than the PL experiment.
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Affiliation(s)
- Gourab Rana
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Sharmistha Das
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Prajit Kumar Singha
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Fariyad Ali
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Rohan Maji
- Department of Chemistry, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
| | - Anindya Datta
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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3
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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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4
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Wang C, Chen Z, Xiao S, He J. Visible light-induced hole transfer in single-nanoplate Cu 1.81S-CdS heterostructures. NANOSCALE 2024; 16:5401-5408. [PMID: 38376462 DOI: 10.1039/d3nr06450f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
The separation and transfer of photogenerated carriers in semiconducting materials are essential processes that determine the efficiency of optoelectronic devices and photocatalysts, and transient absorption spectroscopy provides a powerful support for exploring the diffusion and recombination of photogenerated electrons and holes. Herein, high-quality Cu1.81S nanoplates were synthesized by a hot injection method, and were used as starting templates for the preparation of Cu1.81S-CdS heterojunctions and CdS nanoplates by cation exchange. Their carrier dynamics were investigated by transient absorption spectroscopy, which revealed that photogenerated holes may be transferred from the CdS phase to the Cu1.81S phase under 400 nm excitation. This process is in the opposite direction to the hole transfer induced by near-infrared localized surface plasmon resonance in copper sulfide heterostructures. Moreover, density functional theory calculations were used to further explain the visible light-induced hole transport process. This transfer is a potential way to increase the rate of H2 production and enhance the photostability of the catalyst.
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Affiliation(s)
- Chang Wang
- Hunan Key Laboratory of Nanophotonics and Devices, School of Physics, Central South University, Changsha 410083, China.
| | - Zhaozhe Chen
- Hunan Key Laboratory of Nanophotonics and Devices, School of Physics, Central South University, Changsha 410083, China.
| | - Si Xiao
- Hunan Key Laboratory of Nanophotonics and Devices, School of Physics, Central South University, Changsha 410083, China.
| | - Jun He
- Hunan Key Laboratory of Nanophotonics and Devices, School of Physics, Central South University, Changsha 410083, China.
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Strandell DP, Zenatti D, Nagpal P, Ghosh A, Dirin DN, Kovalenko MV, Kambhampati P. Hot Excitons Cool in Metal Halide Perovskite Nanocrystals as Fast as CdSe Nanocrystals. ACS NANO 2024; 18:1054-1062. [PMID: 38109401 DOI: 10.1021/acsnano.3c10301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
The idea of phonon bottlenecks has long been pursued in nanoscale materials for their application in hot exciton devices, such as photovoltaics. Decades ago, it was shown that there is no quantum phonon bottleneck in strongly confined quantum dots due to their physics of quantum confinement. More recently, it was proposed that there are hot phonon bottlenecks in metal halide perovskites due to their physics. Recent work has called into question these bottlenecks in metal halide perovskites. Here, we compare hot exciton cooling in a range of sizes of CsPbBr3 nanocrystals from weakly to strongly confined. These results are compared to strongly confined CdSe quantum dots of two sizes and degrees of quantum confinement. CdSe is a model system as a ruler for measuring hot exciton cooling being fast, by virtue of its efficient Auger-assisted processes. By virtue of 3 ps time resolution, the hot exciton photoluminescence can now be directly observed, which is the most direct measure of the presence of hot excitons and their lifetimes. The hot exciton photoluminescence decays on nearly the same 2 ps time scale on both the weakly confined perovskite and the larger CdSe quantum dots, much faster than the 10 ps cooling predicted by transient absorption experiments. The smaller CdSe quantum dot has still faster cooling, as expected from quantum size effects. The quantum dots of perovskites show extremely fast hot exciton cooling, decaying faster than detection limits of <1 ps, even faster than the CdSe system, suggesting the efficiency of Auger processes in these metal halide perovskite nanocrystals and especially in their quantum dot form. These results across a range of sizes of nanocrystals reveal extremely fast hot exciton cooling at high exciton density, independent of composition, but dependent upon size. Hence these metal halide perovskite nanocrystals seem to cool heavily following quantum dot physics.
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Affiliation(s)
| | - Davide Zenatti
- Department of Chemistry, McGill University, Montreal, H3A 0B8, Canada
| | - Priya Nagpal
- Department of Chemistry, McGill University, Montreal, H3A 0B8, Canada
| | - Arnab Ghosh
- Department of Chemistry, McGill University, Montreal, H3A 0B8, Canada
| | - Dmitry N Dirin
- Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - Maksym V Kovalenko
- Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
- Empa-Swiss Federal Laboratories for Materials Science and Technology, 8600 Dubendorf, Switzerland
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Strandell D, Dirin D, Zenatti D, Nagpal P, Ghosh A, Raino G, Kovalenko MV, Kambhampati P. Enhancing Multiexcitonic Emission in Metal-Halide Perovskites by Quantum Confinement. ACS NANO 2023; 17:24910-24918. [PMID: 38079478 DOI: 10.1021/acsnano.3c06497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
Semiconductor metal halide perovskite nanocrystals have been under intense investigation for their promise in a variety of optoelectronic applications, which arises from their remarkable properties of defect tolerance and efficient light emission. Recently, quantum dot versions of perovskite nanocrystals have been available, enabling investigation of how quantum size effects control optical function and performance in these quantum dots (QD), past their well-known covalent II-VI analogues. We perform time-resolved photoluminescence (t-PL) experiments on CsPbBr3 perovskite nanocrystals spanning in diameter from 5.8 nm strongly confined quantum dots to 18 nm weakly confined quantum dots. Experiments are performed with sufficient time resolution of 3 ps to observe the interaction energies and recombination kinetics from excitons to multiexcitons. Comparing the same sized QD reveals that perovskite QD have a larger radiative rate constant for emission from X than CdSe QD due to a larger oscillator strength. The multiexciton (MX) regime reveals that perovskite QD emit brightly and with more focused bandwidth than equivalent sized CdSe QD enabling more spectrally pure brightness. The MX kinetics reveals that the perovskite QD maintain efficient radiative decay, effectively competing with Auger recombination. These experiments reveal that the strongly confined QD of perovskites can be efficient multiexcitonic emitters, such as in high brightness light emitting diodes, especially in the blue.
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Affiliation(s)
- Dallas Strandell
- Department of Chemistry, McGill University, Montreal, H3A 0B8, Canada
| | - Dmitry Dirin
- Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - Davide Zenatti
- Department of Chemistry, McGill University, Montreal, H3A 0B8, Canada
| | - Priya Nagpal
- Department of Chemistry, McGill University, Montreal, H3A 0B8, Canada
| | - Arnab Ghosh
- Department of Chemistry, McGill University, Montreal, H3A 0B8, Canada
| | - Gabriele Raino
- Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
- Empa - Swiss Federal Laboratories for Materials Science and Technology, 8600 Dubendorf, Switzerland
| | - Maksym V Kovalenko
- Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
- Empa - Swiss Federal Laboratories for Materials Science and Technology, 8600 Dubendorf, Switzerland
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Rose PA, Krich JJ. Interpretations of High-Order Transient Absorption Spectroscopies. J Phys Chem Lett 2023; 14:10849-10855. [PMID: 38032056 DOI: 10.1021/acs.jpclett.3c02491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
Transient absorption (TA) spectroscopy is an invaluable tool for determining the energetics and dynamics of excited states. When pump intensities are sufficiently high, TA spectra include both the generally desired third-order response and responses that are higher in order in the field amplitudes. Recent work demonstrated that pump-intensity-dependent TA measurements allow separating the orders of response, but the information content in those higher orders has not been described. We give a general framework for understanding high-order TA spectra. We extend to higher order the fundamental processes of standard TA: ground-state bleach (GSB), stimulated emission (SE), and excited-state absorption (ESA). Each order introduces two new processes: SE and ESA from previously inaccessible highly excited states and negations of lower-order processes. We show the new spectral and dynamical information at each order and show how the relative signs of the signals in different orders can be used to identify which processes dominate.
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Affiliation(s)
- Peter A Rose
- Department of Physics, University of Ottawa, Ottawa ON K1N 6N5, Canada
| | - Jacob J Krich
- Department of Physics, University of Ottawa, Ottawa ON K1N 6N5, Canada
- Nexus for Quantum Technologies, University of Ottawa, Ottawa ON K1N 6N5, Canada
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8
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Jin N, Sun Y, Shi W, Wang P, Nagaoka Y, Cai T, Wu R, Dube L, Nyiera HN, Liu Y, Mani T, Wang X, Zhao J, Chen O. Type-I CdS/ZnS Core/Shell Quantum Dot-Gold Heterostructural Nanocrystals for Enhanced Photocatalytic Hydrogen Generation. J Am Chem Soc 2023; 145:21886-21896. [PMID: 37768875 DOI: 10.1021/jacs.3c06065] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2023]
Abstract
Developing Type-I core/shell quantum dots is of great importance toward fabricating stable and sustainable photocatalysts. However, the application of Type-I systems has been limited due to the strongly confined photogenerated charges by the energy barrier originating from the wide-bandgap shell material. In this project, we found that through the decoration of Au satellite-type domains on the surface of Type-I CdS/ZnS core/shell quantum dots, such an energy barrier can be effectively overcome and an over 400-fold enhancement of photocatalytic H2 evolution rate was achieved compared to bare CdS/ZnS quantum dots. Transient absorption spectroscopic studies indicated that the charges can be effectively extracted and subsequently transferred to surrounding molecular substrates in a subpicosecond time scale in such hybrid nanocrystals. Based on density functional theory calculations, the ultrafast charge separation rates were ascribed to the formation of intermediate Au2S layer at the semiconductor-metal interface, which can successfully offset the energy confinement introduced by the ZnS shell. Our findings not only provide insightful understandings on charge carrier dynamics in semiconductor-metal heterostructural materials but also pave the way for the future design of quantum dot-based hybrid photocatalytic systems.
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Affiliation(s)
- Na Jin
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Yonglei Sun
- Institute of Materials Science, University of Connecticut, Storrs Mansfield, Connecticut 06269, United States
| | - Wenwu Shi
- School of Physical Science and Technology, Southwest University, Chongqing 400715, People's Republic of China
- Institute of Information Technology, Shenzhen Institute of Information Technology, Shenzhen 518172, China
| | - Ping Wang
- Key Laboratory of Preparation and Applications of Environmental Friendly Materials of the Ministry of Education, College of Chemistry, Jilin Normal University, Changchun 130103, China
| | - Yasutaka Nagaoka
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Tong Cai
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Rongzhen Wu
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Lacie Dube
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Hawi N Nyiera
- Department of Chemistry, University of Connecticut, Storrs Mansfield, Connecticut 06269, United States
| | - Yuzi Liu
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Tomoyasu Mani
- Department of Chemistry, University of Connecticut, Storrs Mansfield, Connecticut 06269, United States
| | - Xinzhong Wang
- Institute of Information Technology, Shenzhen Institute of Information Technology, Shenzhen 518172, China
| | - Jing Zhao
- Institute of Materials Science, University of Connecticut, Storrs Mansfield, Connecticut 06269, United States
- Department of Chemistry, University of Connecticut, Storrs Mansfield, Connecticut 06269, United States
| | - Ou Chen
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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9
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Thrupthika T, Nataraj D, Ramya S, Sangeetha A, Thangadurai TD. Induced UV photon sensing properties in narrow bandgap CdTe quantum dots through controlling hot electron dynamics. Phys Chem Chem Phys 2023; 25:25331-25343. [PMID: 37702661 DOI: 10.1039/d3cp02424e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/14/2023]
Abstract
Mn-doped CdTe (Mn-CdTe) quantum dot (QD) as well as quantum dot solid (QD solid) nanostructures are formed and the established structures are confirmed through HR-TEM analysis. The dynamics of charge carriers in both doped & undoped QD and QD solid structures were investigated by transient absorption (TA) spectroscopy. A slow band edge bleach recovery is obtained for Mn-doped CdTe QD and CdTe QD solid systems at room temperature. Additionally, a blue shifted broad bleach behaviour is identified for the Mn-CdTe QD solid system, which is attributed to hot exciton formation in the solid upon photoexcitation with a higher photon energy than the band gap energy (hν > Eg). This noteworthy process of generation of hot excitons and slow charge recombination occurs by means of a synergetic action of the Mn dopant in the host CdTe QD solid system as well as the extended electronic wave function between the coupled QD solid. Apart from the Mn-assisted delayed relaxation of hot electrons in the QD solid, a suppression in dark current as well as a high ION/IOFF ratio of 3203.12 at 1 V is observed in the Mn-CdTe QD-solid based photosensitized device in the visible region. Furthermore, we were able to improve the UV photon harvesting property in a narrow band gap Mn-CdTe QD solid through reducing the higher excited carrier's energy losses.
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Affiliation(s)
- Thankappan Thrupthika
- Quantum Materials & Devices Laboratory, Department of Physics, Bharathiar University, Coimbatore, Tamil Nadu 641 046, India.
| | - Devaraj Nataraj
- Quantum Materials & Devices Laboratory, Department of Physics, Bharathiar University, Coimbatore, Tamil Nadu 641 046, India.
- UGC-CPEPA Centre for Advanced Studies in Physics for the Development of Solar Energy Materials and Devices, Department of Physics, Bharathiar University, Coimbatore, Tamil Nadu, 641 046, India
| | - Subramaniam Ramya
- Quantum Materials & Devices Laboratory, Department of Physics, Bharathiar University, Coimbatore, Tamil Nadu 641 046, India.
| | - Arumugam Sangeetha
- Quantum Materials & Devices Laboratory, Department of Physics, Bharathiar University, Coimbatore, Tamil Nadu 641 046, India.
| | - T Daniel Thangadurai
- KPR Institute of Engineering and Technology, Coimbatore, Tamil Nadu, 641 407, India.
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Sung YM, Kim TG, Yun DJ, Chae BG, Park H, Lee HS, Kim JH, Jun S, Sul S. Effect of trifluoroacetic acid on InP/ZnSe/ZnS quantum dots: mimicking the surface trap and their effects on the photophysical properties. RSC Adv 2023; 13:28160-28164. [PMID: 37753393 PMCID: PMC10518562 DOI: 10.1039/d3ra05441a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 09/18/2023] [Indexed: 09/28/2023] Open
Abstract
Understanding the precise effects of defects on the photophysical properties of quantum dots (QDs) is essential to their development with near-unity luminescence. Because of the complicated nature of defects in QDs, the origins and detailed roles of the defects still remain rarely understood. In this regard, we used detailed chemical analysis to investigate the effect of surface defects on the optical properties of InP/ZnSe/ZnS QDs by introducing shell defects through controlled trifluoroacetic acid (TFA) etching. TFA treatment on the InP/ZnSe/ZnS QDs partially removed the ZnS shell as well as ligands and reduced the quantum yield by generating energetically deep surface traps. The surface defects of QDs by TFA cause charged trap sites inducing an Auger recombination process with a rate of ca. 200 ps. Based on these results, we proposed possible trap-assisted non-radiative decay pathways between the band-edge state and surface deep traps in InP/ZnSe/ZnS QDs.
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Affiliation(s)
- Young Mo Sung
- Analytical Engineering Group, Samsung Advanced Institute of Technology 130, Samsung-ro, Yeongtong-gu Suwon-si Gyeonggi-do 16678 South Korea
| | - Tae-Gon Kim
- Organic Materials Lab, Samsung Advanced Institute of Technology 130, Samsung-ro, Yeongtong-gu Suwon-si Gyeonggi-do 16678 South Korea
| | - Dong-Jin Yun
- Analytical Engineering Group, Samsung Advanced Institute of Technology 130, Samsung-ro, Yeongtong-gu Suwon-si Gyeonggi-do 16678 South Korea
| | - Byeong Gyu Chae
- Analytical Engineering Group, Samsung Advanced Institute of Technology 130, Samsung-ro, Yeongtong-gu Suwon-si Gyeonggi-do 16678 South Korea
| | - Hyokeun Park
- Analytical Engineering Group, Samsung Advanced Institute of Technology 130, Samsung-ro, Yeongtong-gu Suwon-si Gyeonggi-do 16678 South Korea
| | - Hyo Sug Lee
- Analytical Engineering Group, Samsung Advanced Institute of Technology 130, Samsung-ro, Yeongtong-gu Suwon-si Gyeonggi-do 16678 South Korea
| | - Jung-Hwa Kim
- Analytical Engineering Group, Samsung Advanced Institute of Technology 130, Samsung-ro, Yeongtong-gu Suwon-si Gyeonggi-do 16678 South Korea
| | - Shinae Jun
- Organic Materials Lab, Samsung Advanced Institute of Technology 130, Samsung-ro, Yeongtong-gu Suwon-si Gyeonggi-do 16678 South Korea
| | - Soohwan Sul
- Analytical Engineering Group, Samsung Advanced Institute of Technology 130, Samsung-ro, Yeongtong-gu Suwon-si Gyeonggi-do 16678 South Korea
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11
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Strandell DP, Ghosh A, Zenatti D, Nagpal P, Kambhampati P. Direct Observation of Higher Multiexciton Formation and Annihilation in CdSe Quantum Dots. J Phys Chem Lett 2023:6904-6911. [PMID: 37498205 DOI: 10.1021/acs.jpclett.3c01627] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
Most experiments on multiexcitons (MX) in quantum dots focused on the biexciton (XX), which is now well-understood. In contrast, there is little understanding of higher MX in quantum dots as a result of their difficulty to observe. Here, we apply time-resolved photoluminescence (t-PL) spectroscopy with 3 ps time resolution, sufficient to directly resolve previously unobserved spectral dynamics of a higher MX in CdSe quantum dots. These experiments resolve the controversy of the sequence of MX emissions, revealing that the higher channels sequentially populate the lower channels. There is a strong dependence of MX recombination kinetics upon a higher MX state, following a universal volume scaling law for Auger recombination for larger dots. Smaller dots show deviations for higher MX. In addition to triexcitons (3X), these experiments reveal MX up to the tetraexciton (4X). These experiments provide a direct observation of MX formation and annihilation in quantum dots. The impact of this observation is a step toward designing quantum dots to exploit higher MX processes.
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Affiliation(s)
- Dallas P Strandell
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Arnab Ghosh
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Davide Zenatti
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Priya Nagpal
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
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12
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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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13
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Rebmann J, Werners H, Johst F, Dohrmann M, Staechelin YU, Strelow C, Mews A, Kipp T. Cation Exchange during the Synthesis of Colloidal Type-II ZnSe-Dot/CdS-Rod Nanocrystals. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2023; 35:1238-1248. [PMID: 36818587 PMCID: PMC9933437 DOI: 10.1021/acs.chemmater.2c03278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 12/13/2022] [Indexed: 06/18/2023]
Abstract
Cation exchange is known to occur during the synthesis of colloidal semiconductor heteronanoparticles, affecting their band gap and thus altering their optoelectronic properties. It is often neglected, especially when anisotropic heterostructures are discussed. We present a study on the role of cation exchange inevitably occurring during the growth of anisotropic dot-in-rod structures consisting of a spherical ZnSe core enclosed by a rod-shaped CdS shell. The material combination exhibits a type-II band alignment. Two reactions are compared: the shell-growth reaction of CdS on ZnSe and an exchange-only reaction of ZnSe cores to CdSe. Transmission electron microscopy and a comprehensive set of optical spectroscopy data, including linear and time-resolved absorption and fluorescence data, prove that cation exchange from ZnSe to CdSe is the dominant process in the initial stages of the shell-growth reaction. The degree of cation exchange before significant shell growth starts was determined to be about 50%, highlighting the importance of cation exchange during the heteronanostructure growth.
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14
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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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15
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Jasrasaria D, Weinberg D, Philbin JP, Rabani E. Simulations of nonradiative processes in semiconductor nanocrystals. J Chem Phys 2022; 157:020901. [PMID: 35840368 DOI: 10.1063/5.0095897] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The description of carrier dynamics in spatially confined semiconductor nanocrystals (NCs), which have enhanced electron-hole and exciton-phonon interactions, is a great challenge for modern computational science. These NCs typically contain thousands of atoms and tens of thousands of valence electrons with discrete spectra at low excitation energies, similar to atoms and molecules, that converge to the continuum bulk limit at higher energies. Computational methods developed for molecules are limited to very small nanoclusters, and methods for bulk systems with periodic boundary conditions are not suitable due to the lack of translational symmetry in NCs. This perspective focuses on our recent efforts in developing a unified atomistic model based on the semiempirical pseudopotential approach, which is parameterized by first-principle calculations and validated against experimental measurements, to describe two of the main nonradiative relaxation processes of quantum confined excitons: exciton cooling and Auger recombination. We focus on the description of both electron-hole and exciton-phonon interactions in our approach and discuss the role of size, shape, and interfacing on the electronic properties and dynamics for II-VI and III-V semiconductor NCs.
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Affiliation(s)
- Dipti Jasrasaria
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Daniel Weinberg
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - John P Philbin
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Eran Rabani
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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16
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Sun Q, Gong J, Yan X, Wu Y, Cui R, Tian W, Jin S, Wang Y. Elucidating the Unique Hot Carrier Cooling in Two-Dimensional Inorganic Halide Perovskites: The Role of Out-of-Plane Carrier-Phonon Coupling. NANO LETTERS 2022; 22:2995-3002. [PMID: 35318847 DOI: 10.1021/acs.nanolett.2c00203] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Two-dimensional (2D) halide perovskites represent the natural semiconductor quantum wells (QWs), which hold great promise for optoelectronics. However, due to the hybrid structure of Ruddlesden-Popper 2D perovskites, the intrinsic nature of hot-carrier kinetics remains shielded within. Herein, we adopt CsPbBr3 nanoplates as a model system to reveal the intrinsic carrier dynamics in inorganic perovskite QWs. Interestingly, we revealed an ultrafast and hot-phonon-bottleneck (HPB)-free carrier cooling in monodisperse CsPbBr3 QWs, which is in sharp contrast to the bulk and nanocrystalline perovskites. The absence of HPB was attributed to the efficient out-of-plane triplet-exciton-LO-phonon coupling in 2D perovskites because of the structural anisotropy. Accordingly, the HPB can be activated by shutting down the out-of-plane energy loss route through forming the layer-stacked perovskite superlattice. The controllable on and off of HPB may provide new possibilities in optoelectronic devices and these findings deepen the understanding of a hot-carrier cooling mechanism in 2D perovskites.
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Affiliation(s)
- Qi Sun
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics and Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Jialong Gong
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics and Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Xianchang Yan
- State Key Laboratory of Molecular Reaction Dynamics and the Dynamic Research Center for Energy and Environmental Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Yuting Wu
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics and Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Rongrong Cui
- State Key Laboratory of Molecular Reaction Dynamics and the Dynamic Research Center for Energy and Environmental Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Wenming Tian
- State Key Laboratory of Molecular Reaction Dynamics and the Dynamic Research Center for Energy and Environmental Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Shengye Jin
- State Key Laboratory of Molecular Reaction Dynamics and the Dynamic Research Center for Energy and Environmental Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Yue Wang
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics and Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
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17
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Privitera A, Macaluso E, Chiesa A, Gabbani A, Faccio D, Giuri D, Briganti M, Giaconi N, Santanni F, Jarmouni N, Poggini L, Mannini M, Chiesa M, Tomasini C, Pineider F, Salvadori E, Carretta S, Sessoli R. Direct detection of spin polarization in photoinduced charge transfer through a chiral bridge. Chem Sci 2022; 13:12208-12218. [PMID: 36349110 PMCID: PMC9601404 DOI: 10.1039/d2sc03712b] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 10/03/2022] [Indexed: 12/26/2022] Open
Abstract
It is well assessed that the charge transport through a chiral potential barrier can result in spin-polarized charges. The possibility of driving this process through visible photons holds tremendous potential for several aspects of quantum information science, e.g., the optical control and readout of qubits. In this context, the direct observation of this phenomenon via spin-sensitive spectroscopies is of utmost importance to establish future guidelines to control photo-driven spin selectivity in chiral structures. Here, we provide direct proof that time-resolved electron paramagnetic resonance (EPR) can be used to detect long-lived spin polarization generated by photoinduced charge transfer through a chiral bridge. We propose a system comprising CdSe quantum dots (QDs), as a donor, and C60, as an acceptor, covalently linked through a saturated oligopeptide helical bridge (χ) with a rigid structure of ∼10 Å. Time-resolved EPR spectroscopy shows that the charge transfer in our system results in a C60 radical anion, whose spin polarization maximum is observed at longer times with respect to that of the photogenerated C60 triplet state. Notably, the theoretical modelling of the EPR spectra reveals that the observed features may be compatible with chirality-induced spin selectivity, but the electronic features of the QD do not allow the unambiguous identification of the CISS effect. Nevertheless, we identify which parameters need optimization for unambiguous detection and quantification of the phenomenon. This work lays the basis for the optical generation and direct manipulation of spin polarization induced by chirality. Our work provides a first attempt to directly detect the spin polarisation of Chiral-Induced Spin Selectivity (CISS) effect by studying the photoinduced electron transfer in a CdSe Quantum Dot-chiral bridge-fullerene derivative (QD–χ–C60) system.![]()
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Affiliation(s)
- Alberto Privitera
- Department of Chemistry and NIS Centre, University of Torino, Via Giuria 7, Torino, I-10125, Italy
- Department of Chemistry “U. Schiff” (DICUS), University of Florence & UdR INSTM Firenze, Via della Lastruccia 3-13, Sesto Fiorentino, I-50019, Italy
| | - Emilio Macaluso
- Department of Mathematical, Physical and Computer Sciences, University of Parma & UdR INSTM, I-43124, Parma, Italy
- INFN–Sezione di Milano-Bicocca, gruppo collegato di Parma, I-43124 Parma, Italy
| | - Alessandro Chiesa
- Department of Mathematical, Physical and Computer Sciences, University of Parma & UdR INSTM, I-43124, Parma, Italy
- INFN–Sezione di Milano-Bicocca, gruppo collegato di Parma, I-43124 Parma, Italy
| | - Alessio Gabbani
- Department of Chemistry and Industrial Chemistry, University of Pisa & UdR INSTM Pisa, Via Moruzzi 13, Pisa, I-56124, Italy
| | - Davide Faccio
- Department of Chemistry “Giacomo Ciamician”, University of Bologna, Via Selmi 2, Bologna, I-40126, Italy
| | - Demetra Giuri
- Department of Chemistry “Giacomo Ciamician”, University of Bologna, Via Selmi 2, Bologna, I-40126, Italy
| | - Matteo Briganti
- Department of Chemistry “U. Schiff” (DICUS), University of Florence & UdR INSTM Firenze, Via della Lastruccia 3-13, Sesto Fiorentino, I-50019, Italy
| | - Niccolò Giaconi
- Department of Chemistry “U. Schiff” (DICUS), University of Florence & UdR INSTM Firenze, Via della Lastruccia 3-13, Sesto Fiorentino, I-50019, Italy
- Department of Industrial Engineering (DIEF), University of Florence & UdR INSTM Firenze, Via Santa Marta 3, Firenze, I-50139, Italy
| | - Fabio Santanni
- Department of Chemistry “U. Schiff” (DICUS), University of Florence & UdR INSTM Firenze, Via della Lastruccia 3-13, Sesto Fiorentino, I-50019, Italy
| | - Nabila Jarmouni
- Department of Chemistry and Industrial Chemistry, University of Pisa & UdR INSTM Pisa, Via Moruzzi 13, Pisa, I-56124, Italy
| | - Lorenzo Poggini
- CNR-ICCOM, Via Madonna del Piano 10, Sesto Fiorentino, I-50019, Italy
| | - Matteo Mannini
- Department of Chemistry “U. Schiff” (DICUS), University of Florence & UdR INSTM Firenze, Via della Lastruccia 3-13, Sesto Fiorentino, I-50019, Italy
| | - Mario Chiesa
- Department of Chemistry and NIS Centre, University of Torino, Via Giuria 7, Torino, I-10125, Italy
| | - Claudia Tomasini
- Department of Chemistry “Giacomo Ciamician”, University of Bologna, Via Selmi 2, Bologna, I-40126, Italy
| | - Francesco Pineider
- Department of Chemistry and Industrial Chemistry, University of Pisa & UdR INSTM Pisa, Via Moruzzi 13, Pisa, I-56124, Italy
| | - Enrico Salvadori
- Department of Chemistry and NIS Centre, University of Torino, Via Giuria 7, Torino, I-10125, Italy
| | - Stefano Carretta
- Department of Mathematical, Physical and Computer Sciences, University of Parma & UdR INSTM, I-43124, Parma, Italy
- INFN–Sezione di Milano-Bicocca, gruppo collegato di Parma, I-43124 Parma, Italy
| | - Roberta Sessoli
- Department of Chemistry “U. Schiff” (DICUS), University of Florence & UdR INSTM Firenze, Via della Lastruccia 3-13, Sesto Fiorentino, I-50019, Italy
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18
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Sung YM, Kim TG, Yun DJ, Lim M, Ko DS, Jung C, Won N, Park S, Jeon WS, Lee HS, Kim JH, Jun S, Sul S, Hwang S. Increasing the Energy Gap between Band-Edge and Trap States Slows Down Picosecond Carrier Trapping in Highly Luminescent InP/ZnSe/ZnS Quantum Dots. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2102792. [PMID: 34636144 DOI: 10.1002/smll.202102792] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 08/09/2021] [Indexed: 06/13/2023]
Abstract
Non-toxic InP-based nanocrystals have been developed for promising candidates for commercial optoelectronic applications and they still require further improvement on photophysical properties, compared to Cd-based quantum dots (QDs), for better device efficiency and long-term stability. It is, therefore, essential to understand the precise mechanism of carrier trapping even in the state-of-the-art InP-based QD with near-unity luminescence. Here, it is shown that using time-resolved spectroscopic measurements of systematically size-controlled InP/ZnSe/ZnS core/shell/shell QDs with the quantum yield close to one, carrier trapping decreases with increasing the energy difference between band-edge and trap states, indicating that the process follows the energy gap law, well known in molecular photochemistry for nonradiative internal conversion between two electronic states. Similar to the molecular view of the energy gap law, it is found that the energy gap between the band-edge and trap states is closely associated with ZnSe phonons that assist carrier trapping into defects in highly luminescent InP/ZnSe/ZnS QDs. These findings represent a striking departure from the generally accepted view of carrier trapping mechanism in QDs in the Marcus normal region, providing a step forward understanding how excitons in nanocrystals interact with traps, and offering valuable guidance for making highly efficient and stable InP-based QDs.
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Affiliation(s)
- Young Mo Sung
- Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., 130 Samsung-ro, Suwon, 16678, Republic of Korea
| | - Tae-Gon Kim
- Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., 130 Samsung-ro, Suwon, 16678, Republic of Korea
| | - Dong-Jin Yun
- Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., 130 Samsung-ro, Suwon, 16678, Republic of Korea
| | - Mihye Lim
- Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., 130 Samsung-ro, Suwon, 16678, Republic of Korea
| | - Dong-Su Ko
- Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., 130 Samsung-ro, Suwon, 16678, Republic of Korea
| | - Changhoon Jung
- Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., 130 Samsung-ro, Suwon, 16678, Republic of Korea
| | - Nayoun Won
- Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., 130 Samsung-ro, Suwon, 16678, Republic of Korea
| | - Sungjun Park
- Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., 130 Samsung-ro, Suwon, 16678, Republic of Korea
| | - Woo Sung Jeon
- Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., 130 Samsung-ro, Suwon, 16678, Republic of Korea
| | - Hyo Sug Lee
- Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., 130 Samsung-ro, Suwon, 16678, Republic of Korea
| | - Jung-Hwa Kim
- Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., 130 Samsung-ro, Suwon, 16678, Republic of Korea
| | - Shinae Jun
- Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., 130 Samsung-ro, Suwon, 16678, Republic of Korea
| | - Soohwan Sul
- Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., 130 Samsung-ro, Suwon, 16678, Republic of Korea
| | - Sungwoo Hwang
- Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., 130 Samsung-ro, Suwon, 16678, Republic of Korea
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19
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Zhang J, Sakai H, Suzuki K, Hasobe T, Tkachenko NV, Chang IY, Hyeon-Deuk K, Kaji H, Teranishi T, Sakamoto M. Near-Unity Singlet Fission on a Quantum Dot Initiated by Resonant Energy Transfer. J Am Chem Soc 2021; 143:17388-17394. [PMID: 34647732 DOI: 10.1021/jacs.1c04731] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The conversion of a high-energy photon into two excitons using singlet fission (SF) has stimulated a variety of studies in fields from fundamental physics to device applications. However, efficient SF has only been achieved in limited systems, such as solid crystals and covalent dimers. Here, we established a novel system by assembling 4-(6,13-bis(2-(triisopropylsilyl)ethynyl)pentacen-2-yl)benzoic acid (Pc) chromophores on nanosized CdTe quantum dots (QDs). A near-unity SF (198 ± 5.7%) initiated by interfacial resonant energy transfer from CdTe to surface Pc was obtained. The unique arrangement of Pc determined by the surface atomic configuration of QDs is the key factor realizing unity SF. The triplet-triplet annihilation was remarkably suppressed due to the rapid dissociation of triplet pairs, leading to long-lived free triplets. In addition, the low light-harvesting ability of Pc in the visible region was promoted by the efficient energy transfer (99 ± 5.8%) from the QDs to Pc. The synergistically enhanced light-harvesting ability, high triplet yield, and long-lived triplet lifetime of the SF system on nanointerfaces could pave the way for an unmatched advantage of SF.
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Affiliation(s)
- Jie Zhang
- Department of Chemistry, Graduate School of Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Hayato Sakai
- Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Katsuaki Suzuki
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Taku Hasobe
- Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Nikolai V Tkachenko
- Chemistry and Advanced Materials Group, Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, FI33720 Tampere, Finland
| | - I-Ya Chang
- Department of Chemistry, Kyoto University, Kyoto, Kyoto 606-8502, Japan
| | - Kim Hyeon-Deuk
- Department of Chemistry, Kyoto University, Kyoto, Kyoto 606-8502, Japan
| | - Hironori Kaji
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Toshiharu Teranishi
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Masanori Sakamoto
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
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20
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Ruhman S. Solving Quantum-Dot Excitonic Riddles with Absolute Pump-Probe Spectroscopy. J Phys Chem Lett 2021; 12:9336-9343. [PMID: 34549584 DOI: 10.1021/acs.jpclett.1c02408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Absolute absorption changes in molecular flash photolysis experiments are routinely translated into molar extinction coefficients and oscillator strengths of reactive intermediates. These direct quantum chemical investigation and allow precise concentration readings in later experiments. In this Perspective we show how a similar approach can deliver crucial information for interpreting transient absorption spectra in colloidal semiconductor quantum dots. The intrinsic complexity of such samples stemming from the inhomogeneity of particle size, shape, and surface chemistry poses unique challenges to mechanistic assignment of ultrafast pump-probe measurements. We will describe applications of this approach to elucidate the photophysics of quantum confined nanocrystals made of various semiconducting materials. These case studies demonstrate how, faced with conflicting interpretations, it has pointed in the right direction in assessing single and multiple exciton generation and relaxation, in searches for ultrafast carrier trapping and scavenging, and in tests of band edge level structure and state degeneracies.
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Affiliation(s)
- Sanford Ruhman
- The Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
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21
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Marri I, Ossicini S. Multiple exciton generation in isolated and interacting silicon nanocrystals. NANOSCALE 2021; 13:12119-12142. [PMID: 34250528 DOI: 10.1039/d1nr01747k] [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
An important challenge in the field of renewable energy is the development of novel nanostructured solar cell devices which implement low-dimensional materials to overcome the limits of traditional photovoltaic systems. For optimal energy conversion in photovoltaic devices, one important requirement is that the full energy of the solar spectrum is effectively used. In this context, the possibility of exploiting features and functionalities induced by the reduced dimensionality of the nanocrystalline phase, in particular by the quantum confinement of the electronic density, can lead to a better use of the carrier excess energy and thus to an increment of the thermodynamic conversion efficiency of the system. Carrier multiplication, i.e. the generation of multiple electron-hole pairs after absorption of one single high-energy photon (with energy at least twice the energy gap of the system), can be exploited to maximize cell performance, promoting a net reduction of loss mechanisms. Over the past fifteen years, carrier multiplication has been recorded in a large variety of semiconductor nanocrystals and other nanostructures. Owing to the role of silicon in solar cell applications, the mission of this review is to summarize the progress in this fascinating research field considering carrier multiplication in Si-based low-dimensional systems, in particular Si nanocrystals, both from the experimental and theoretical point of view, with special attention given to the results obtained by ab initio calculations.
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Affiliation(s)
- Ivan Marri
- Department of Sciences and Methods for Engineering, University of Modena e Reggio Emilia, 42122 Reggio Emilia, Italy.
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22
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Kambhampati P. Nanoparticles, Nanocrystals, and Quantum Dots: What are the Implications of Size in Colloidal Nanoscale Materials? J Phys Chem Lett 2021; 12:4769-4779. [PMID: 33984241 DOI: 10.1021/acs.jpclett.1c00754] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Semiconductor nanoparticles (NP) or nanocrystals (NC) have been investigated for many decades, with particular acceleration in interest upon the discovery of quantum confinement effects thereby yielding quantum dots (QD) from certain well-grown NC. The term NP is commonly used in the case of metal and wide gap semiconductor nanocrystals. The term NC is commonly used in semiconductor nanocrystals, whether covalent II-VI or ionic perovskites, that are colloidally grown. The term QD applies to select semiconductor nanocrystals for whom their size is on the order of the excitonic Bohr radius. In the case of colloidal particles on the nanometer length scale, these terms are often used carelessly and interchangeably. The words have specific meaning in relationship to specific physical effects which give rise to specific key processes that can be measured. Here, we provide a Perspective on the ways in which size confers function across different families of NP. In this way, we aim to find ways to identify their similarities and differences by providing the correct semantics for discussion of the salient processes.
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23
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Yan C, Weinberg D, Jasrasaria D, Kolaczkowski MA, Liu ZJ, Philbin JP, Balan AD, Liu Y, Schwartzberg AM, Rabani E, Alivisatos AP. Uncovering the Role of Hole Traps in Promoting Hole Transfer from Multiexcitonic Quantum Dots to Molecular Acceptors. ACS NANO 2021; 15:2281-2291. [PMID: 33336575 DOI: 10.1021/acsnano.0c08158] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Understanding electronic dynamics in multiexcitonic quantum dots (QDs) is important for designing efficient systems useful in high power scenarios, such as solar concentrators and multielectron charge transfer. The multiple charge carriers within a QD can undergo undesired Auger recombination events, which rapidly annihilate carriers on picosecond time scales and generate heat from absorbed photons instead of useful work. Compared to the transfer of multiple electrons, the transfer of multiple holes has proven to be more difficult due to slower hole transfer rates. To probe the competition between Auger recombination and hole transfer in CdSe, CdS, and CdSe/CdS QDs of varying sizes, we synthesized a phenothiazine derivative with optimized functionalities for binding to QDs as a hole accepting ligand and for spectroscopic observation of hole transfer. Transient absorption spectroscopy was used to monitor the photoinduced absorption features from both trapped holes and oxidized ligands under excitation fluences where the averaged initial number of excitons in a QD ranged from ∼1 to 19. We observed fluence-dependent hole transfer kinetics that last around 100 ps longer than the predicted Auger recombination lifetimes, and the transfer of up to 3 holes per QD. Theoretical modeling of the kinetics suggests that binding of hole acceptors introduces trapping states significantly different from those in native QDs passivated with oleate ligands. Holes in these modified trap states have prolonged lifetimes, which promotes the hole transfer efficiency. These results highlight the beneficial role of hole-trapping states in devising hole transfer pathways in QD-based systems under multiexcitonic conditions.
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Affiliation(s)
- Chang Yan
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Daniel Weinberg
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Dipti Jasrasaria
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Matthew A Kolaczkowski
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Zi-Jie Liu
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - John P Philbin
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Arunima D Balan
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Yi Liu
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Adam M Schwartzberg
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Eran Rabani
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 69978, Israel
| | - A Paul Alivisatos
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States
- Kavli Energy NanoScience Institute, Berkeley, California 94720, United States
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24
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Dana J, Haggag OS, Dehnel J, Mor M, Lifshitz E, Ruhman S. Testing the fate of nascent holes in CdSe nanocrystals with sub-10 fs pump-probe spectroscopy. NANOSCALE 2021; 13:1982-1987. [PMID: 33443522 DOI: 10.1039/d0nr07651a] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Numerous studies have reported that transient absorption spectra in core CdSe nanocrystals do not register state filling in 1Sh, an absence which has profound consequences in light-emitting applications. It has been assigned alternatively to rapid hole trapping, or to distribution over a dense degenerate valence band manifold which includes dark states. Here we attempt to observe early contributions of nascent holes to the bleaching of the band edge exciton transition by conducting 1Se1Sh pump-1Se1Sh probe spectroscopy with <10 fs laser pulses on organic ligand passivated CdSe crystals. The results show no rapidly hole-state filling effects in transient absorption measurements even at the earliest delay, despite the use of pulses which are capable of resolving all dissipation mechanisms reflected in the homogeneous 1Se1Sh bandwidth. This proves that neither hole trapping nor rapid redistribution of the nascent hole over energetically available valence band states can explain the absence of hole contributions to band edge bleaching, calling for a mechanistic review of this phenomenon.
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Affiliation(s)
- Jayanta Dana
- The Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
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25
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Affiliation(s)
- Christopher Melnychuk
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
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26
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Numerical Analysis of the Detailed Balance of Multiple Exciton Generation Solar Cells with Nonradiative Recombination. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10165558] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this study, we analyzed the nonradiative recombination impact of multiple exciton generation solar cells (MEGSCs) with a revised detailed balance (DB) limit. The nonideal quantum yield (QY) of a material depends on the surface defects or the status of the material. Thus, its QY shape deviates from the ideal QY because of carrier losses. We used the ideal reverse saturation current variation in the DB of MEGSCs to explain the impact of nonradiative recombination. We compared ideal and nonideal QYs with the nonradiative recombination into the DB of MEGSCs under one-sun and full-light concentration. Through this research, we seek to develop a strategy to maintain MEGSC performance.
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27
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Zhang Y, Wu G, Liu F, Ding C, Zou Z, Shen Q. Photoexcited carrier dynamics in colloidal quantum dot solar cells: insights into individual quantum dots, quantum dot solid films and devices. Chem Soc Rev 2020; 49:49-84. [PMID: 31825404 DOI: 10.1039/c9cs00560a] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The certified power conversion efficiency (PCE) record of colloidal quantum dot solar cells (QDSCs) has considerably improved from below 4% to 16.6% in the last few years. However, the record PCE value of QDSCs is still substantially lower than the theoretical efficiency. So far, there have been several reviews on recent and significant achievements in QDSCs, but reviews on photoexcited carrier dynamics in QDSCs are scarce. The photovoltaic performances of QDSCs are still limited by the photovoltage, photocurrent and fill factor that are mainly determined by the photoexcited carrier dynamics, including carrier (or exciton) generation, carrier extraction or transfer, and the carrier recombination process, in the devices. In this review, the photoexcited carrier dynamics in the whole QDSCs, originating from individual quantum dots (QDs) to the entire device as well as the characterization methods used for analyzing the photoexcited carrier dynamics are summarized and discussed. The recent research including photoexcited multiple exciton generation (MEG), hot electron extraction, and carrier transfer between adjacent QDs, as well as carrier injection and recombination at each interface of QDSCs are discussed in detail herein. The influence of photoexcited carrier dynamics on the physiochemical properties of QDs and photovoltaic performances of QDSC devices is also discussed.
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Affiliation(s)
- Yaohong Zhang
- Faculty of Informatics and Engineering, The University of Electro-Communications, Tokyo 182-8585, Japan.
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28
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Kim T, Jung SI, Ham S, Chung H, Kim D. Elucidation of Photoluminescence Blinking Mechanism and Multiexciton Dynamics in Hybrid Organic-Inorganic Perovskite Quantum Dots. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1900355. [PMID: 31237396 DOI: 10.1002/smll.201900355] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 06/07/2019] [Indexed: 05/25/2023]
Abstract
Halide perovskites (ABX3 ) have emerged as promising materials in the past decade owing to their superior photophysical properties, rendering them potential candidates as solar cells, light-emitting diode displays, and lasing materials. To optimize their utilization into optoelectronic devices, fundamental understanding of the optical behaviors is necessary. To reveal the comprehensive structure-property relationship, CH3 NH3 PbBr3 (MAPbBr3 ) perovskite quantum dots (PQDs) of three different sizes are prepared by controlling the precipitation temperature. Photoluminescence (PL) blinking, a key process that governs the emission efficiency of the PQD materials, is investigated in detail by the time-resolved spectroscopic measurements of individual dots. The nature of the generated species in the course of blinking events is identified, and the mechanism governing the PL blinking is studied as a function of PQD sizes. Further, the practical applicability of MAPbBr3 PQDs is assessed by studying the multiexciton dynamics under high photoexcitation intensity under which most of the display devices work. Ultrafast transient absorption spectroscopy helped in uncovering the volume-dependent Auger recombination rates, which are further explored by comparing the early-time transitions related to surface trap states and higher band states.
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Affiliation(s)
- Taehee Kim
- Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, 120-749, Seoul, Korea
| | - Seok Il Jung
- Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, 120-749, Seoul, Korea
| | - Sujin Ham
- Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, 120-749, Seoul, Korea
| | - Heejae Chung
- Inorganic Materials Lab, Samsung Advanced Institute of Technology, 16678, Suwon, Gyeonggi-do, Korea
| | - Dongho Kim
- Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, 120-749, Seoul, Korea
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29
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Lian Z, Sakamoto M, Kobayashi Y, Tamai N, Ma J, Sakurai T, Seki S, Nakagawa T, Lai MW, Haruta M, Kurata H, Teranishi T. Anomalous Photoinduced Hole Transport in Type I Core/Mesoporous-Shell Nanocrystals for Efficient Photocatalytic H 2 Evolution. ACS NANO 2019; 13:8356-8363. [PMID: 31282648 DOI: 10.1021/acsnano.9b03826] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Controlling the carrier dynamics in a semiconductor nanoparticulate photocatalyst is the key to developing catalytic activity. Generally, type I band alignment is unsuitable for photocatalysts because the photoinduced carriers accumulate in the narrow bandgap semiconductor. To avoid the termination of reactions and/or photocorrosion of materials caused by carrier accumulation, it is common to employ type II band alignment for photoenergy conversion systems instead of type I. However, CdS/ZnS core/mesoporous-shell heterostructures show superior photocatalytic activity despite having type I band alignment that is generally unfavorable for photocatalytic reactions. Transient absorption spectroscopy and time-resolved microwave conductivity revealed efficient photoinduced hole transfer from the CdS phase to the ZnS phase. The defect-mediated hole transfer from the CdS to the ZnS phase resulted in long-lived charge separation (>2.4 ms) leading to high photocatalytic performance. This study provides insight into defect-mediated carrier transfer in nanoparticulate photocatalysts, which could be used as a guideline for the design of highly active and stable nanoparticulate photocatalysts.
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Affiliation(s)
- Zichao Lian
- Institute for Chemical Research , Kyoto University , Gokasho, Uji, Kyoto 611-0011 , Japan
| | - Masanori Sakamoto
- Institute for Chemical Research , Kyoto University , Gokasho, Uji, Kyoto 611-0011 , Japan
| | - Yoichi Kobayashi
- Department of Applied Chemistry, College of Life Sciences , Ritsumeikan University , 1-1-1 Noji-higashi , Kusatsu , Shiga 525-8577 , Japan
| | - Naoto Tamai
- Department of Chemistry, School of Science and Technology , Kwansei Gakuin University , 2-1 Gakuen , Sanda , Hyogo 669-1337 , Japan
| | - Jun Ma
- Department of Molecular Engineering, Graduate School of Engineering , Kyoto University , Nishikyo-ku , Kyoto 615-8510 , Japan
| | - Tsuneaki Sakurai
- Department of Molecular Engineering, Graduate School of Engineering , Kyoto University , Nishikyo-ku , Kyoto 615-8510 , Japan
| | - Shu Seki
- Department of Molecular Engineering, Graduate School of Engineering , Kyoto University , Nishikyo-ku , Kyoto 615-8510 , Japan
| | - Tatsuo Nakagawa
- Optical Instruments Division , Unisoku Co., Ltd. , Kasugano 2-4-3 , Hirakata , Osaka 573-0131 , Japan
| | - Ming-Wei Lai
- Institute for Chemical Research , Kyoto University , Gokasho, Uji, Kyoto 611-0011 , Japan
| | - Mitsutaka Haruta
- Institute for Chemical Research , Kyoto University , Gokasho, Uji, Kyoto 611-0011 , Japan
| | - Hiroki Kurata
- Institute for Chemical Research , Kyoto University , Gokasho, Uji, Kyoto 611-0011 , Japan
| | - Toshiharu Teranishi
- Institute for Chemical Research , Kyoto University , Gokasho, Uji, Kyoto 611-0011 , Japan
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30
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Kirschner MS, Diroll BT, Brumberg A, Leonard AA, Hannah DC, Chen LX, Schaller RD. Optical Signatures of Transiently Disordered Semiconductor Nanocrystals. ACS NANO 2018; 12:10008-10015. [PMID: 30226751 DOI: 10.1021/acsnano.8b04435] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The optoelectronic properties of semiconductor nanocrystals (NCs) have led to efforts to integrate them as the active material in light-emitting diodes, solid-state lighting, and lasers. Understanding related high carrier injection conditions is therefore critical as resultant thermal effects can impact optical properties. The physical integrity of NCs is indeed questionable as recent transient X-ray diffraction studies have suggested that nanoscopic particles reversibly lose crystalline order, or melt, under high fluence photoexcitation. Informed by such studies, here, we examine CdSe NCs under elevated fluences to determine the impact of lattice disordering on optical properties. To this end, we implement intensity-dependent transient absorption using both one- and two-pump methods where the latter effectively subtracts out the NC optical signatures associated with lower fluence photoexcitation, especially band-edge features. At elevated fluences, we observe a long-lived induced absorption at a lower energy than the crystalline-NC bandgap across a wide range of sizes that follows power-dependent trends and kinetics consistent with the prior transient X-ray measurements. NC photoluminescence studies provide further evidence that melting influences optical properties. These methods of characterizing bandgap narrowing caused by lattice disordering could facilitate routes to improved optical amplification and band-edge emission at high excitation density.
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Affiliation(s)
- Matthew S Kirschner
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
| | | | - Alexandra Brumberg
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
| | - Ariel A Leonard
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
| | - Daniel C Hannah
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
| | - Lin X Chen
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
| | - Richard D Schaller
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
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31
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Righetto M, Bolzonello L, Volpato A, Amoruso G, Panniello A, Fanizza E, Striccoli M, Collini E. Deciphering hot- and multi-exciton dynamics in core-shell QDs by 2D electronic spectroscopies. Phys Chem Chem Phys 2018; 20:18176-18183. [PMID: 29961782 PMCID: PMC6044327 DOI: 10.1039/c8cp02574f] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
2D electronic spectroscopy maps acquired in different configurations unveil intraband hot carrier cooling and interband multi-exciton recombination dynamics.
Although the harnessing of multiple and hot excitons is a prerequisite for many of the groundbreaking applications of semiconductor quantum dots (QDs), the characterization of their dynamics through conventional spectroscopic techniques is cumbersome. Here, we show how a careful analysis of 2DES maps acquired in different configurations (BOXCARS and pump–probe geometry) allows the tracking and visualization of intraband Auger relaxation mechanisms, driving the hot carrier cooling, and interband bi- and tri-exciton recombination dynamics. The results obtained on archetypal core–shell CdSe/ZnS QDs suggest that, given the global analysis of the resulting datasets, 2D electronic spectroscopy techniques can successfully and efficiently dispel the intertwined dynamics of fast and ultrafast recombination processes in nanomaterials. Hence, we propose this analysis scheme to be used in future research on novel quantum confined systems.
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Affiliation(s)
- Marcello Righetto
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy.
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32
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Hot-electron transfer in quantum-dot heterojunction films. Nat Commun 2018; 9:2310. [PMID: 29899361 PMCID: PMC5998019 DOI: 10.1038/s41467-018-04623-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 05/08/2018] [Indexed: 11/08/2022] Open
Abstract
Thermalization losses limit the photon-to-power conversion of solar cells at the high-energy side of the solar spectrum, as electrons quickly lose their energy relaxing to the band edge. Hot-electron transfer could reduce these losses. Here, we demonstrate fast and efficient hot-electron transfer between lead selenide and cadmium selenide quantum dots assembled in a quantum-dot heterojunction solid. In this system, the energy structure of the absorber material and of the electron extracting material can be easily tuned via a variation of quantum-dot size, allowing us to tailor the energetics of the transfer process for device applications. The efficiency of the transfer process increases with excitation energy as a result of the more favorable competition between hot-electron transfer and electron cooling. The experimental picture is supported by time-domain density functional theory calculations, showing that electron density is transferred from lead selenide to cadmium selenide quantum dots on the sub-picosecond timescale. Efficient use of high-energy, or “hot”, carriers could increase the efficiency of solar cells, provided efficient extraction of electrons at a specific energy. Here, the authors show the presence of hot-electron transfer between two quantum dot species, allowing facile optimization of the extraction energy.
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33
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Orfield NJ, Majumder S, McBride JR, Yik-Ching Koh F, Singh A, Bouquin SJ, Casson JL, Johnson AD, Sun L, Li X, Shih CK, Rosenthal SJ, Hollingsworth JA, Htoon H. Photophysics of Thermally-Assisted Photobleaching in "Giant" Quantum Dots Revealed in Single Nanocrystals. ACS NANO 2018; 12:4206-4217. [PMID: 29709173 DOI: 10.1021/acsnano.7b07450] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Quantum dots (QDs) are steadily being implemented as down-conversion phosphors in market-ready display products to enhance color rendering, brightness, and energy efficiency. However, for adequate longevity, QDs must be encased in a protective barrier that separates them from ambient oxygen and humidity, and device architectures are designed to avoid significant heating of the QDs as well as direct contact between the QDs and the excitation source. In order to increase the utility of QDs in display technologies and to extend their usefulness to more demanding applications as, for example, alternative phosphors for solid-state lighting (SSL), QDs must retain their photoluminescence emission properties over extended periods of time under conditions of high temperature and high light flux. Doing so would simplify the fabrication costs for QD display technologies and enable QDs to be used as down-conversion materials in light-emitting diodes for SSL, where direct-on-chip configurations expose the emitters to temperatures approaching 100 °C and to photon fluxes from 0.1 W/mm2 to potentially 10 W/mm2. Here, we investigate the photobleaching processes of single QDs exposed to controlled temperature and photon flux. In particular, we investigate two types of room-temperature-stable core/thick-shell QDs, known as "giant" QDs for which shell growth is conducted using either a standard layer-by-layer technique or by a continuous injection method. We determine the mechanistic pathways responsible for thermally-assisted photodegradation, distinguishing effects of hot-carrier trapping and QD charging. The findings presented here will assist in the further development of advanced QD heterostructures for maximum device lifetime stability.
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Affiliation(s)
- Noah J Orfield
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Somak Majumder
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - James R McBride
- Department of Chemistry , Vanderbilt University , Nashville , Tennessee 37235 , United States
| | - Faith Yik-Ching Koh
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Ajay Singh
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Sarah J Bouquin
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Joanna L Casson
- Chemistry Division , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Alex D Johnson
- Physics Department and Center for Complex Quantum Systems , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Liuyang Sun
- Physics Department and Center for Complex Quantum Systems , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Xiaoqin Li
- Physics Department and Center for Complex Quantum Systems , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Chih-Kang Shih
- Physics Department and Center for Complex Quantum Systems , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Sandra J Rosenthal
- Department of Chemistry , Vanderbilt University , Nashville , Tennessee 37235 , United States
| | - Jennifer A Hollingsworth
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Han Htoon
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
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Seiler H, Palato S, Sonnichsen C, Baker H, Kambhampati P. Seeing Multiexcitons through Sample Inhomogeneity: Band-Edge Biexciton Structure in CdSe Nanocrystals Revealed by Two-Dimensional Electronic Spectroscopy. NANO LETTERS 2018; 18:2999-3006. [PMID: 29589448 DOI: 10.1021/acs.nanolett.8b00470] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The electronic structure of multiexcitons significantly impacts the performance of nanostructures in lasing and light-emitting applications. However, these multiexcitons remain poorly understood due to their complexity arising from many-body physics. Standard transient-absorption and photoluminescence spectroscopies are unable to unambiguously distinguish effects of sample inhomogeneity from exciton-biexciton interactions. Here, we exploit the energy and time resolution of two-dimensional electronic spectroscopy to access the electronic structure of the band-edge biexciton in colloidal CdSe quantum dots. By removing effects of inhomogeneities, we show that the band-edge biexciton structure must consist of a discrete manifold of electronic states. Furthermore, the biexciton states within the manifold feature distinctive binding energies. Our findings have direct implications for optical gain thresholds and efficiency droop in light-emitting devices and provide experimental measures of many-body physics in nanostructures.
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Affiliation(s)
- Hélène Seiler
- Department of Chemistry , McGill University , Montreal , Quebec H3A 0B8 , Canada
| | - Samuel Palato
- Department of Chemistry , McGill University , Montreal , Quebec H3A 0B8 , Canada
| | - Colin Sonnichsen
- Department of Chemistry , McGill University , Montreal , Quebec H3A 0B8 , Canada
| | - Harry Baker
- Department of Chemistry , McGill University , Montreal , Quebec H3A 0B8 , Canada
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35
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Zhang L, Xu Q, Liu M, Kong L, Jiao M, Mu H, Wang D, Wang H, Chen J, Yang C. Temperature and Wavelength Dependence of Energy Transfer Process Between Quantized States and Surface States in CdSe Quantum Dots. NANOSCALE RESEARCH LETTERS 2017; 12:222. [PMID: 28347128 PMCID: PMC5366993 DOI: 10.1186/s11671-017-1971-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 03/01/2017] [Indexed: 06/06/2023]
Abstract
Temperature and wavelength dependence of energy transfer (ET) process between quantized states and surface trap states of CdSe quantum dots was investigated, respectively. The experimental results demonstrate that the photoluminescence (PL) intensity of the quantized states decreases with respect to the trap state emission, especially at lower temperatures. The observed ET process between quantized states and trap states which is influenced by the thermal population behavior. At the same temperature, the silver films can greatly enhance the energy transfer (ET) rate from the quantized states to trap states due to surface plasmonic coupling effect.
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Affiliation(s)
- Lei Zhang
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China
| | - Qinfeng Xu
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China.
| | - Mingliang Liu
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China
| | - Lingbin Kong
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China
| | - Mengmeng Jiao
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China
| | - Haifeng Mu
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China
| | - Dehua Wang
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China
| | - Honggang Wang
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China
- Ministerial Key Laboratory of JGMT, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Jiannong Chen
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China
| | - Chuanlu Yang
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China.
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36
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Liu B, Meng Y, Ruan X, Wang F, Liu W, Song F, Wang X, Wu J, He L, Zhang R, Xu Y. Coupled relaxation channels of excitons in monolayer MoSe 2. NANOSCALE 2017; 9:18546-18551. [PMID: 29164206 DOI: 10.1039/c7nr05174c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Using ultrafast degenerate pump-probe spectroscopy, we have investigated the ultrafast exciton dynamics of monolayer MoSe2 at different pump fluences. The exciton-exciton annihilation, typically occurring tens of picoseconds after pump excitation, has been found to have a substantial correlation with the initial relaxation process dominated by the defect trapping of excitons. A new exciton-exciton annihilation model has been proposed by introducing a coupling term that accounts for the initial relaxation contribution. This coupling term can be tuned by varying the pump excitation intensity and at a high intensity it vanishes due to the full occupation of the defect states. At the same time, the final electron-hole recombination is found to be affected by the heat accumulation effect originating from the high intensity pump pulses.
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Affiliation(s)
- Bo Liu
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, Collaborative Innovation Center of Advanced Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, People's Republic of China.
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37
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Zhang Z, Chen Z, Yuan L, Chen W, Yang J, Wang B, Wen X, Zhang J, Hu L, Stride JA, Conibeer GJ, Patterson RJ, Huang S. A New Passivation Route Leading to Over 8% Efficient PbSe Quantum-Dot Solar Cells via Direct Ion Exchange with Perovskite Nanocrystals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29. [PMID: 28922475 DOI: 10.1002/adma.201703214] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 07/23/2017] [Indexed: 05/05/2023]
Abstract
Colloidal quantum dots (QDs) are promising candidate materials for photovoltaics (PV) owing to the tunable bandgap and low-cost solution processability. Lead selenide (PbSe) QDs are particularly attractive to PV applications due to the efficient multiple-exciton generation and carrier transportation. However, surface defects arising from the oxidation of the PbSe QDs have been the major limitation for their development in PV. Here, a new passivation method for chlorinated PbSe QDs via ion exchange with cesium lead halide (Br, I) perovskite nanocrystals is reported. The surface chloride ions on the as-synthesized QDs can be partially exchanged with bromide or iodide ions from the perovskite nanocrystals, hence forming a hybrid halide passivation. Consistent with the improved photoluminescence quantum yield, the champion PV device fabricated with these PbSe QDs achieves a PCE of 8.2%, compared to 7.3% of that fabricated with the untreated QDs. This new method also leads to devices with excellent air-stability, retaining at least 93% of their initial PCEs after being stored in ambient conditions for 57 d. This is considered as the first reported PbSe QD solar cell with a PCE of over 8% to date.
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Affiliation(s)
- Zhilong Zhang
- Australian Centre for Advanced Photovoltaics, University of New South Wales, Sydney, 2052, Australia
| | - Zihan Chen
- Australian Centre for Advanced Photovoltaics, University of New South Wales, Sydney, 2052, Australia
| | - Lin Yuan
- Australian Centre for Advanced Photovoltaics, University of New South Wales, Sydney, 2052, Australia
| | - Weijian Chen
- Australian Centre for Advanced Photovoltaics, University of New South Wales, Sydney, 2052, Australia
| | - Jianfeng Yang
- Australian Centre for Advanced Photovoltaics, University of New South Wales, Sydney, 2052, Australia
| | - Bo Wang
- Australian Centre for Advanced Photovoltaics, University of New South Wales, Sydney, 2052, Australia
| | - Xiaoming Wen
- Australian Centre for Advanced Photovoltaics, University of New South Wales, Sydney, 2052, Australia
| | - Jianbing Zhang
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China
| | - Long Hu
- Australian Centre for Advanced Photovoltaics, University of New South Wales, Sydney, 2052, Australia
| | - John A Stride
- School of Chemistry, University of New South Wales, Sydney, 2052, Australia
| | - Gavin J Conibeer
- Australian Centre for Advanced Photovoltaics, University of New South Wales, Sydney, 2052, Australia
| | - Robert J Patterson
- Australian Centre for Advanced Photovoltaics, University of New South Wales, Sydney, 2052, Australia
| | - Shujuan Huang
- Australian Centre for Advanced Photovoltaics, University of New South Wales, Sydney, 2052, Australia
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Chang IY, Kim D, Hyeon-Deuk K. Control of Multiple Exciton Generation and Electron-Phonon Coupling by Interior Nanospace in Hyperstructured Quantum Dot Superlattice. ACS APPLIED MATERIALS & INTERFACES 2017; 9:32080-32088. [PMID: 28838230 DOI: 10.1021/acsami.7b08137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The possibility of precisely manipulating interior nanospace, which can be adjusted by ligand-attaching down to the subnanometer regime, in a hyperstructured quantum dot (QD) superlattice (QDSL) induces a new kind of collective resonant coupling among QDs and opens up new opportunities for developing advanced optoelectric and photovoltaic devices. Here, we report the first real-time dynamics simulations of the multiple exciton generation (MEG) in one-, two-, and three-dimensional (1D, 2D, and 3D) hyperstructured H-passivated Si QDSLs, accounting for thermally fluctuating band energies and phonon dynamics obtained by finite-temperature ab initio molecular dynamics simulations. We computationally demonstrated that the MEG was significantly accelerated, especially in the 3D QDSL compared to the 1D and 2D QDSLs. The MEG acceleration in the 3D QDSL was almost 1.9 times the isolated QD case. The dimension-dependent MEG acceleration was attributed not only to the static density of states but also to the dynamical electron-phonon couplings depending on the dimensionality of the hyperstructured QDSL, which is effectively controlled by the interior nanospace. Such dimension-dependent modifications originated from the short-range quantum resonance among component QDs and were intrinsic to the hyperstructured QDSL. We propose that photoexcited dynamics including the MEG process can be effectively controlled by only manipulating the interior nanospace of the hyperstructured QDSL without changing component QD size, shape, compositions, ligand, etc.
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Affiliation(s)
- I-Ya Chang
- Department of Chemistry, Kyoto University , Kyoto 606-8502, Japan
- PRESTO, Japan Science and Technology Agency , 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - DaeGwi Kim
- Department of Applied Physics, Osaka City University , Osaka 558-8585, Japan
| | - Kim Hyeon-Deuk
- Department of Chemistry, Kyoto University , Kyoto 606-8502, Japan
- PRESTO, Japan Science and Technology Agency , 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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Kershaw SV, Rogach AL. Carrier Multiplication Mechanisms and Competing Processes in Colloidal Semiconductor Nanostructures. MATERIALS (BASEL, SWITZERLAND) 2017; 10:E1095. [PMID: 28927007 PMCID: PMC5615749 DOI: 10.3390/ma10091095] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 09/10/2017] [Accepted: 09/14/2017] [Indexed: 12/14/2022]
Abstract
Quantum confined semiconductor nanoparticles, such as colloidal quantum dots, nanorods and nanoplatelets have broad extended absorption spectra at energies above their bandgaps. This means that they can absorb light at high photon energies leading to the formation of hot excitons with finite excited state lifetimes. During their existence, the hot electron and hole that comprise the exciton may start to cool as they relax to the band edge by phonon mediated or Auger cooling processes or a combination of these. Alongside these cooling processes, there is the possibility that the hot exciton may split into two or more lower energy excitons in what is termed carrier multiplication (CM). The fission of the hot exciton to form lower energy multiexcitons is in direct competition with the cooling processes, with the timescales for multiplication and cooling often overlapping strongly in many materials. Once CM has been achieved, the next challenge is to preserve the multiexcitons long enough to make use of the bonus carriers in the face of another competing process, non-radiative Auger recombination. However, it has been found that Auger recombination and the several possible cooling processes can be manipulated and usefully suppressed or retarded by engineering the nanoparticle shape, size or composition and by the use of heterostructures, along with different choices of surface treatments. This review surveys some of the work that has led to an understanding of the rich carrier dynamics in semiconductor nanoparticles, and that has started to guide materials researchers to nanostructures that can tilt the balance in favour of efficient CM with sustained multiexciton lifetimes.
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Affiliation(s)
- Stephen V Kershaw
- Department of Materials Science and Engineering and Centre for Functional Photonics (CFP), City University of Hong Kong, Hong Kong S.A.R., China.
| | - Andrey L Rogach
- Department of Materials Science and Engineering and Centre for Functional Photonics (CFP), City University of Hong Kong, Hong Kong S.A.R., China.
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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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Kotin PA, Bubenov SS, Mordvinova NE, Dorofeev SG. AgCl-doped CdSe quantum dots with near-IR photoluminescence. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:1156-1166. [PMID: 28685116 PMCID: PMC5480357 DOI: 10.3762/bjnano.8.117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 05/08/2017] [Indexed: 06/07/2023]
Abstract
We report the synthesis of colloidal CdSe quantum dots doped with a novel Ag precursor: AgCl. The addition of AgCl causes dramatic changes in the morphology of synthesized nanocrystals from spherical nanoparticles to tetrapods and finally to large ellipsoidal nanoparticles. Ellipsoidal nanoparticles possess an intensive near-IR photoluminescence ranging up to 0.9 eV (ca. 1400 nm). In this article, we explain the reasons for the formation of the ellipsoidal nanoparticles as well as the peculiarities of the process. The structure, Ag content, and optical properties of quantum dots are also investigated. The optimal conditions for maximizing both the reaction yield and IR photoluminescence quantum yield are found.
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Affiliation(s)
- Pavel Aleksandrovich Kotin
- Department of Chemistry, Lomonosov Moscow State University, 1 building 3 Leninskie Gory, Moscow 119991, Russia
| | - Sergey Sergeevich Bubenov
- Department of Chemistry, Lomonosov Moscow State University, 1 building 3 Leninskie Gory, Moscow 119991, Russia
| | - Natalia Evgenievna Mordvinova
- Department of Chemistry, Lomonosov Moscow State University, 1 building 3 Leninskie Gory, Moscow 119991, Russia
- Laboratoire CRISMAT, UMR6508, CNRS-ENSICAEN, 6 boulevard Marechal Juin, Caen 14050, France
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42
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Pietryga JM, Park YS, Lim J, Fidler AF, Bae WK, Brovelli S, Klimov VI. Spectroscopic and Device Aspects of Nanocrystal Quantum Dots. Chem Rev 2017; 116:10513-622. [PMID: 27677521 DOI: 10.1021/acs.chemrev.6b00169] [Citation(s) in RCA: 400] [Impact Index Per Article: 57.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The field of nanocrystal quantum dots (QDs) is already more than 30 years old, and yet continuing interest in these structures is driven by both the fascinating physics emerging from strong quantum confinement of electronic excitations, as well as a large number of prospective applications that could benefit from the tunable properties and amenability toward solution-based processing of these materials. The focus of this review is on recent advances in nanocrystal research related to applications of QD materials in lasing, light-emitting diodes (LEDs), and solar energy conversion. A specific underlying theme is innovative concepts for tuning the properties of QDs beyond what is possible via traditional size manipulation, particularly through heterostructuring. Examples of such advanced control of nanocrystal functionalities include the following: interface engineering for suppressing Auger recombination in the context of QD LEDs and lasers; Stokes-shift engineering for applications in large-area luminescent solar concentrators; and control of intraband relaxation for enhanced carrier multiplication in advanced QD photovoltaics. We examine the considerable recent progress on these multiple fronts of nanocrystal research, which has resulted in the first commercialized QD technologies. These successes explain the continuing appeal of this field to a broad community of scientists and engineers, which in turn ensures even more exciting results to come from future exploration of this fascinating class of materials.
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Affiliation(s)
- Jeffrey M Pietryga
- Nanotechnology and Advanced Spectroscopy Team, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Young-Shin Park
- Nanotechnology and Advanced Spectroscopy Team, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States.,Center for High Technology Materials, University of New Mexico , Albuquerque, New Mexico 87131, United States
| | - Jaehoon Lim
- Nanotechnology and Advanced Spectroscopy Team, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Andrew F Fidler
- Nanotechnology and Advanced Spectroscopy Team, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Wan Ki Bae
- Photo-Electronic Hybrids Research Center, Korea Institute of Science and Technology , Seoul 02792, Korea
| | - Sergio Brovelli
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca , I-20125 Milano, Italy
| | - Victor I Klimov
- Nanotechnology and Advanced Spectroscopy Team, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
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Cohen E, Gdor I, Romero E, Yochelis S, van Grondelle R, Paltiel Y. Achieving Exciton Delocalization in Quantum Dot Aggregates Using Organic Linker Molecules. J Phys Chem Lett 2017; 8:1014-1018. [PMID: 28195481 DOI: 10.1021/acs.jpclett.6b02980] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The design of new complex structures containing semiconductor quantum dots offers a means to create a variety of new meso-solids and molecules. The control of the coupling properties between the dots, accompanied by the energetic tunability of the dots themselves, paves the way toward the application and use of novel quantum properties. Here we present our approach to alteration of interdot coupling using organic linking molecules in a system of covalently bonded, aggregated quantum dots. We used ultrafast transient absorption measurements to identify marks of exciton delocalization over nearest neighbors to some extent. In linking molecules incorporating a benzene ring, the delocalized electron cloud displayed a profound influence over the interdot effects, leading the way to easy coupling control in quantum-based devices, under ambient conditions.
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Affiliation(s)
- Eyal Cohen
- Department of Applied Physics, The Hebrew University of Jerusalem , Jerusalem 9190401, Israel
| | - Itay Gdor
- Institute of Chemistry, The Hebrew University of Jerusalem , Jerusalem 9190401, Israel
| | - Elisabet Romero
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam , De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Shira Yochelis
- Department of Applied Physics, The Hebrew University of Jerusalem , Jerusalem 9190401, Israel
| | - Rienk van Grondelle
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam , De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Yossi Paltiel
- Department of Applied Physics, The Hebrew University of Jerusalem , Jerusalem 9190401, Israel
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Kisslinger R, Hua W, Shankar K. Bulk Heterojunction Solar Cells Based on Blends of Conjugated Polymers with II⁻VI and IV⁻VI Inorganic Semiconductor Quantum Dots. Polymers (Basel) 2017; 9:E35. [PMID: 30970717 PMCID: PMC6431844 DOI: 10.3390/polym9020035] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 01/16/2017] [Accepted: 01/18/2017] [Indexed: 01/06/2023] Open
Abstract
Bulk heterojunction solar cells based on blends of quantum dots and conjugated polymers are a promising configuration for obtaining high-efficiency, cheaply fabricated solution-processed photovoltaic devices. Such devices are of significant interest as they have the potential to leverage the advantages of both types of materials, such as the high mobility, band gap tunability and possibility of multiple exciton generation in quantum dots together with the high mechanical flexibility and large molar extinction coefficient of conjugated polymers. Despite these advantages, the power conversion efficiency (PCE) of these hybrid devices has remained relatively low at around 6%, well behind that of all-organic or all-inorganic solar cells. This is attributed to major challenges that still need to be overcome before conjugated polymer⁻quantum dot blends can be considered viable for commercial application, such as controlling the film morphology and interfacial structure to ensure efficient charge transfer and charge transport. In this work, we present our findings with respect to the recent development of bulk heterojunctions made from conjugated polymer⁻quantum dot blends, list the ongoing strategies being attempted to improve performance, and highlight the key areas of research that need to be pursued to further develop this technology.
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Affiliation(s)
- Ryan Kisslinger
- Department of Electrical and Computer Engineering, University of Alberta, 9211-116 St., Edmonton, AB T6G 1H9, Canada.
| | - Weidi Hua
- Department of Electrical and Computer Engineering, University of Alberta, 9211-116 St., Edmonton, AB T6G 1H9, Canada.
| | - Karthik Shankar
- Department of Electrical and Computer Engineering, University of Alberta, 9211-116 St., Edmonton, AB T6G 1H9, Canada.
- National Research Council Canada National Institute for Nanotechnology, 11421 Saskatchewan Drive NW, Edmonton, AB T6G 2M9, Canada.
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45
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Boutelle RC, Neuhauser D, Weiss S. Far-Field Super-resolution Detection of Plasmonic Near-Fields. ACS NANO 2016; 10:7955-7962. [PMID: 27501216 DOI: 10.1021/acsnano.6b03873] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We demonstrate a far-field single molecule super-resolution method that maps plasmonic near-fields. The method is largely invariant to fluorescence quenching (arising from probe proximity to a metal), has reduced point-spread-function distortion compared to fluorescent dyes (arising from strong coupling to nanoscopic metallic features), and has a large dynamic range (of 2 orders of magnitude) allowing mapping of plasmonic field-enhancements regions. The method takes advantage of the sensitivity of quantum dot (QD) stochastic blinking to plasmonic near-fields. The modulation of the blinking characteristics thus provides an indirect measure of the local field strength. Since QD blinking can be monitored in the far-field, the method can measure localized plasmonic near-fields at high throughput using a simple far-field optical setup. Using this method, propagation lengths and penetration depths were mapped-out for silver nanowires of different diameters and for different dielectric environments, with a spatial accuracy of ∼15 nm. We initially use sparse sampling to ensure single molecule localization for accurate characterization of the plasmonic near-field with plans to increase density of emitters in further studies. The measured propagation lengths and penetration depths values agree well with Maxwell finite-difference time-domain calculations and with published literature values. This method offers advantages such as low cost, high throughput, and superresolved mapping of localized plasmonic fields at high sensitivity and fidelity.
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Affiliation(s)
| | | | - Shimon Weiss
- Department of Physics, Bar Ilan University , Ramat Gan, 52900, Israel
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46
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Rabouw FT, de Mello Donega C. Excited-State Dynamics in Colloidal Semiconductor Nanocrystals. Top Curr Chem (Cham) 2016; 374:58. [PMID: 27573500 PMCID: PMC5480409 DOI: 10.1007/s41061-016-0060-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 07/23/2016] [Indexed: 11/29/2022]
Abstract
Colloidal semiconductor nanocrystals have attracted continuous worldwide interest over the last three decades owing to their remarkable and unique size- and shape-, dependent properties. The colloidal nature of these nanomaterials allows one to take full advantage of nanoscale effects to tailor their optoelectronic and physical–chemical properties, yielding materials that combine size-, shape-, and composition-dependent properties with easy surface manipulation and solution processing. These features have turned the study of colloidal semiconductor nanocrystals into a dynamic and multidisciplinary research field, with fascinating fundamental challenges and dazzling application prospects. This review focuses on the excited-state dynamics in these intriguing nanomaterials, covering a range of different relaxation mechanisms that span over 15 orders of magnitude, from a few femtoseconds to a few seconds after photoexcitation. In addition to reviewing the state of the art and highlighting the essential concepts in the field, we also discuss the relevance of the different relaxation processes to a number of potential applications, such as photovoltaics and LEDs. The fundamental physical and chemical principles needed to control and understand the properties of colloidal semiconductor nanocrystals are also addressed.
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Affiliation(s)
- Freddy T Rabouw
- Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, PO Box 80000, 3508 TA, Utrecht, The Netherlands.,Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, PO Box 80000, 3508 TA, Utrecht, The Netherlands.,Optical Materials Engineering Laboratory, ETH Zurich, 8092, Zurich, Switzerland
| | - Celso de Mello Donega
- Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, PO Box 80000, 3508 TA, Utrecht, The Netherlands.
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47
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Walsh BR, Saari JI, Krause MM, Nick R, Coe-Sullivan S, Kambhampati P. Surface and interface effects on non-radiative exciton recombination and relaxation dynamics in CdSe/Cd,Zn,S nanocrystals. Chem Phys 2016. [DOI: 10.1016/j.chemphys.2015.11.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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48
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Kriegel I, Scotognella F, Soavi G, Brescia R, Rodríguez-Fernández J, Feldmann J, Lanzani G, Tassone F. Delayed electron relaxation in CdTe nanorods studied by spectral analysis of the ultrafast transient absorption. Chem Phys 2016. [DOI: 10.1016/j.chemphys.2015.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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49
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Leontiadou MA, Al-Otaify A, Kershaw SV, Zhovtiuk O, Kalytchuk S, Mott D, Maenosono S, Rogach AL, Binks DJ. Ultrafast Exciton Dynamics in Cd x Hg (1 − x ) Te alloy Quantum Dots. Chem Phys 2016. [DOI: 10.1016/j.chemphys.2016.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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50
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Hu F, Lv B, Yin C, Zhang C, Wang X, Lounis B, Xiao M. Carrier Multiplication in a Single Semiconductor Nanocrystal. PHYSICAL REVIEW LETTERS 2016; 116:106404. [PMID: 27015498 DOI: 10.1103/physrevlett.116.106404] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Indexed: 06/05/2023]
Abstract
To confirm the existence of the carrier multiplication (CM) effect and estimate its generation efficiency of multiple excitons in semiconductor nanocrystals (NCs), it is imperative to completely exclude the false contribution of charged excitons from the measured CM signal. Here we place single CdSe NCs above an aluminum film and successfully resolve their UV-excited photoluminescence (PL) time trajectories where the true and false CM signals are contained in the blinking "on" and "off" levels, respectively. By analyzing the PL dynamics of the on-level photons, an average CM efficiency of ∼20.2% can be reliably estimated when the UV photon energy is ∼2.46 times the NC energy gap.
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Affiliation(s)
- Fengrui Hu
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Bihu Lv
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Chunyang Yin
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Chunfeng Zhang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Xiaoyong Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Brahim Lounis
- Laboratoire Photonique Numérique et Nanosciences, Université de Bordeaux, Institut d'Optique Graduate School and CNRS, Talence 33405, France
| | - Min Xiao
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, USA
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