1
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Diroll BT, Dabard C, Hua M, Climente JI, Lhuillier E, Ithurria S. Hole Relaxation Bottlenecks in CdSe/CdTe/CdSe Lateral Heterostructures Lead to Bicolor Emission. NANO LETTERS 2024; 24:7934-7940. [PMID: 38885197 DOI: 10.1021/acs.nanolett.4c01250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Concentric lateral CdSe/CdTe/CdSe heterostructures show bicolor photoluminescence from both a red charge transfer band of the CdSe/CdTe interface and a green fluorescence from CdSe. This work uses visible and near-infrared transient spectroscopy measurements to demonstrate that the deviation from Kasha's rule arises from a hole relaxation bottleneck from CdSe to CdTe. Hole transfer can take up to 1 ns, which permits radiative relaxation of excitons remaining in CdSe. Simulations indicate that the hole relaxation bottleneck arises due to the sparse density of states and poor spatial overlap of hole states at energies near the CdSe band edge. The divergent kinetics of transfer for band edge and hot holes is exploited to vary the ratio of green and red photoluminescence with excitation wavelength, providing another knob to control emission color. These findings support the use of lateral heterojunctions as a method for slowing carrier relaxation in two-dimensional materials.
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Affiliation(s)
- Benjamin T Diroll
- Center for Nanoscale Materials, Argonne National Laboratory. 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
| | - Corentin Dabard
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI-Paris, PSL Research University, Sorbonne Université Univ Paris 06, CNRS UMR 8213, 10 rue Vauquelin, Paris 75005, France
| | - Muchuan Hua
- Center for Nanoscale Materials, Argonne National Laboratory. 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
| | - Juan I Climente
- Departament de Química Física i Analítica, Universitat Jaume I, Castelló de la Plana 12080, Spain
| | - Emmanuel Lhuillier
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, 4 Place Jussieu, Paris 75005, France
| | - Sandrine Ithurria
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI-Paris, PSL Research University, Sorbonne Université Univ Paris 06, CNRS UMR 8213, 10 rue Vauquelin, Paris 75005, France
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2
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Cao W, Zhang W, Dong L, Ma Z, Xu J, Gu X, Chen Z. Progress on quantum dot photocatalysts for biomass valorization. EXPLORATION (BEIJING, CHINA) 2023; 3:20220169. [PMID: 38264688 PMCID: PMC10742202 DOI: 10.1002/exp.20220169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 07/31/2023] [Indexed: 01/25/2024]
Abstract
Biomass with abundant reproducible carbon resource holds great promise as an intriguing substitute for fossil fuels in the manufacture of high-value-added chemicals and fuels. Photocatalytic biomass valorization using inexhaustible solar energy enables to accurately break desired chemical bonds or selectively functionalize particular groups, thus emerging as an extremely creative and low carbon cost strategy for relieving the dilemma of the global energy. Quantum dots (QDs) are an outstandingly dynamic class of semiconductor photocatalysts because of their unique properties, which have achieved significant successes in various photocatalytic applications including biomass valorization. In this review, the current development rational design for QDs photocatalytic biomass valorization effectively is highlighted, focusing on the principles of tuning their particle size, structure, and surface properties, with special emphasis on the effect of the ligands for selectively broken chemical bonds (C─O, C─C) of biomass. Finally, the present issues and possibilities within that exciting field are described.
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Affiliation(s)
- Weijing Cao
- Jiangsu Co‐Innovation Center of Efficient Processing and Utilization of Forest ResourcesInternational Innovation Center for Forest Chemicals and MaterialsCollege of Chemical EngineeringNanjing Forestry UniversityNanjingChina
| | - Wenjun Zhang
- Jiangsu Co‐Innovation Center of Efficient Processing and Utilization of Forest ResourcesInternational Innovation Center for Forest Chemicals and MaterialsCollege of Chemical EngineeringNanjing Forestry UniversityNanjingChina
| | - Lin Dong
- Jiangsu Co‐Innovation Center of Efficient Processing and Utilization of Forest ResourcesInternational Innovation Center for Forest Chemicals and MaterialsCollege of Chemical EngineeringNanjing Forestry UniversityNanjingChina
| | - Zhuang Ma
- Leibniz‐Institut für Katalyse e.V.RostockGermany
| | - Jingsan Xu
- School of Chemistry and Physics and Centre for Materials ScienceQueensland University of TechnologyBrisbaneQueenslandAustralia
| | - Xiaoli Gu
- Jiangsu Co‐Innovation Center of Efficient Processing and Utilization of Forest ResourcesInternational Innovation Center for Forest Chemicals and MaterialsCollege of Chemical EngineeringNanjing Forestry UniversityNanjingChina
| | - Zupeng Chen
- Jiangsu Co‐Innovation Center of Efficient Processing and Utilization of Forest ResourcesInternational Innovation Center for Forest Chemicals and MaterialsCollege of Chemical EngineeringNanjing Forestry UniversityNanjingChina
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3
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Tanghe I, Samoli M, Wagner I, Cayan SA, Khan AH, Chen K, Hodgkiss J, Moreels I, Thourhout DV, Hens Z, Geiregat P. Optical gain and lasing from bulk cadmium sulfide nanocrystals through bandgap renormalization. NATURE NANOTECHNOLOGY 2023; 18:1423-1429. [PMID: 37798564 DOI: 10.1038/s41565-023-01521-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 09/06/2023] [Indexed: 10/07/2023]
Abstract
Strongly confined colloidal quantum dots have been investigated for low-cost light emission and lasing for nearly two decades. However, known materials struggle to combine technologically relevant metrics of low-threshold and long inverted-state lifetime with a material gain coefficient fit to match cavity losses, particularly under electrical excitation. Here we show that bulk nanocrystals of CdS combine an exceptionally large material gain of 50,000 cm-1 with best-in-class gain thresholds below a single exciton per nanocrystal and 3 ns gain lifetimes not limited by non-radiative Auger processes. We quantitatively account for these findings by invoking a strong bandgap renormalization effect, unobserved in nanocrystals to date, to the best of our knowledge. Next, we demonstrate broadband amplified spontaneous emission and lasing under quasi-continuous-wave conditions. Our results highlight the prospects of bulk nanocrystals for lasing from solution-processable materials.
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Affiliation(s)
- Ivo Tanghe
- Photonics Research Group, Ghent University, Gent, Belgium
- NoLIMITS Center For Non-Linear Microscopy and Spectroscopy, Ghent University, Gent, Belgium
- Physics and Chemistry of Nanostructures, Ghent University, Gent, Belgium
| | - Margarita Samoli
- Physics and Chemistry of Nanostructures, Ghent University, Gent, Belgium
| | - Isabella Wagner
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand
| | - Servet Ataberk Cayan
- NoLIMITS Center For Non-Linear Microscopy and Spectroscopy, Ghent University, Gent, Belgium
- Physics and Chemistry of Nanostructures, Ghent University, Gent, Belgium
| | - Ali Hossain Khan
- Department of Chemical and Biological Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata, India
- Ghent University, Physics and Chemistry of Nanostructures, Gent, Belgium
| | - Kai Chen
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand
- Robinson Research Institute, Victoria University of Wellington, Wellington, New Zealand
- The Dodd-Walls Centre for Photonic and Quantum Technologies, University of Otago, Dunedin, New Zealand
| | - Justin Hodgkiss
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand
| | - Iwan Moreels
- Physics and Chemistry of Nanostructures, Ghent University, Gent, Belgium
| | - Dries Van Thourhout
- Photonics Research Group, Ghent University, Gent, Belgium
- NoLIMITS Center For Non-Linear Microscopy and Spectroscopy, Ghent University, Gent, Belgium
| | - Zeger Hens
- NoLIMITS Center For Non-Linear Microscopy and Spectroscopy, Ghent University, Gent, Belgium
- Physics and Chemistry of Nanostructures, Ghent University, Gent, Belgium
| | - Pieter Geiregat
- NoLIMITS Center For Non-Linear Microscopy and Spectroscopy, Ghent University, Gent, Belgium.
- Physics and Chemistry of Nanostructures, Ghent University, Gent, Belgium.
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4
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Abstract
Lasers and optical amplifiers based on solution-processable materials have been long-desired devices for their compatibility with virtually any substrate, scalability, and ease of integration with on-chip photonics and electronics. These devices have been pursued across a wide range of materials including polymers, small molecules, perovskites, and chemically prepared colloidal semiconductor nanocrystals, also commonly referred to as colloidal quantum dots. The latter materials are especially attractive for implementing optical-gain media as in addition to being compatible with inexpensive and easily scalable chemical techniques, they offer multiple advantages derived from a zero-dimensional character of their electronic states. These include a size-tunable emission wavelength, low optical gain thresholds, and weak sensitivity of lasing characteristics to variations in temperature. Here we review the status of colloidal nanocrystal lasing devices, most recent advances in this field, outstanding challenges, and the ongoing progress toward technological viable devices including colloidal quantum dot laser diodes.
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Affiliation(s)
- Namyoung Ahn
- Nanotechnology and Advanced Spectroscopy Team, C-PCS, Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Clément Livache
- Nanotechnology and Advanced Spectroscopy Team, C-PCS, Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Valerio Pinchetti
- Nanotechnology and Advanced Spectroscopy Team, C-PCS, Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Victor I Klimov
- Nanotechnology and Advanced Spectroscopy Team, C-PCS, Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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5
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Hudry D, De Backer A, Popescu R, Busko D, Howard IA, Bals S, Zhang Y, Pedrazo-Tardajos A, Van Aert S, Gerthsen D, Altantzis T, Richards BS. Interface Pattern Engineering in Core-Shell Upconverting Nanocrystals: Shedding Light on Critical Parameters and Consequences for the Photoluminescence Properties. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2104441. [PMID: 34697908 DOI: 10.1002/smll.202104441] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/01/2021] [Indexed: 06/13/2023]
Abstract
Advances in controlling energy migration pathways in core-shell lanthanide (Ln)-based hetero-nanocrystals (HNCs) have relied heavily on assumptions about how optically active centers are distributed within individual HNCs. In this article, it is demonstrated that different types of interface patterns can be formed depending on shell growth conditions. Such interface patterns are not only identified but also characterized with spatial resolution ranging from the nanometer- to the atomic-scale. In the most favorable cases, atomic-scale resolved maps of individual particles are obtained. It is also demonstrated that, for the same type of core-shell architecture, the interface pattern can be engineered with thicknesses of just 1 nm up to several tens of nanometers. Total alloying between the core and shell domains is also possible when using ultra-small particles as seeds. Finally, with different types of interface patterns (same architecture and chemical composition of the core and shell domains) it is possible to modify the output color (yellow, red, and green-yellow) or change (improvement or degradation) the absolute upconversion quantum yield. The results presented in this article introduce an important paradigm shift and pave the way toward the emergence of a new generation of core-shell Ln-based HNCs with better control over their atomic-scale organization.
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Affiliation(s)
- Damien Hudry
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Annick De Backer
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, Antwerp, 2020, Belgium
- NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, Antwerp, 2020, Belgium
| | - Radian Popescu
- Laboratory for Electron Microscopy, Karlsruhe Institute of Technology, Engesserstrasse 7, 76131, Karlsruhe, Germany
| | - Dmitry Busko
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Ian A Howard
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
- Light Technology Institute, Karlsruhe Institute of Technology, Engesserstrasse 13, 76131, Karlsruhe, Germany
| | - Sara Bals
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, Antwerp, 2020, Belgium
- NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, Antwerp, 2020, Belgium
| | - Yang Zhang
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, Antwerp, 2020, Belgium
- NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, Antwerp, 2020, Belgium
| | - Adrian Pedrazo-Tardajos
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, Antwerp, 2020, Belgium
- NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, Antwerp, 2020, Belgium
| | - Sandra Van Aert
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, Antwerp, 2020, Belgium
- NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, Antwerp, 2020, Belgium
| | - Dagmar Gerthsen
- Laboratory for Electron Microscopy, Karlsruhe Institute of Technology, Engesserstrasse 7, 76131, Karlsruhe, Germany
| | - Thomas Altantzis
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, Antwerp, 2020, Belgium
- NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, Antwerp, 2020, Belgium
| | - Bryce S Richards
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
- Light Technology Institute, Karlsruhe Institute of Technology, Engesserstrasse 13, 76131, Karlsruhe, Germany
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6
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Sayevich V, Robinson ZL, Kim Y, Kozlov OV, Jung H, Nakotte T, Park YS, Klimov VI. Highly versatile near-infrared emitters based on an atomically defined HgS interlayer embedded into a CdSe/CdS quantum dot. NATURE NANOTECHNOLOGY 2021; 16:673-679. [PMID: 33767383 DOI: 10.1038/s41565-021-00871-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 01/29/2021] [Indexed: 06/12/2023]
Abstract
The availability of colloidal quantum dots with highly efficient, fast and 'non-blinking' near-infrared emission would benefit numerous applications, from advanced optical communication and quantum networks to biomedical diagnostics. Here, we report high-quality near-infrared emitters that are based on well known CdSe/CdS heterostructures. By incorporating an HgS interlayer at the quantum dot core/shell interface, we convert normally visible emitters into highly efficient near-infrared fluorophores. Employing thermodynamically controlled sequential deposition of metal and chalcogen ions, we achieve atomic-level precision in defining the thickness of the HgS interlayer (H). This manifests in 'quantized' jumps of the photoluminescence spectrum when H changes in discrete, atomic steps. The synthesized structures show highly efficient photoluminescence, tunable from 700 to 1,370 nm, and fast radiative rates of ~1/60 ns-1. The emission from individual CdSe/HgS/CdS colloidal quantum dots is virtually blinking free and exhibits nearly perfect single-photon purity. In addition, when incorporated into a light-emitting-diode architecture, these quantum dots demonstrate strong electroluminescence with a sub-bandgap turn-on voltage.
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Affiliation(s)
- Vladimir Sayevich
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Zachary L Robinson
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
| | - Younghee Kim
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Oleg V Kozlov
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Heeyoung Jung
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Tom Nakotte
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA
- Department of Chemical and Materials Engineering, New Mexico State University, Las Cruces, NM, USA
| | - Young-Shin Park
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA
- Center for High Technology Materials, University of New Mexico, Albuquerque, NM, USA
| | - Victor I Klimov
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
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7
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Faraji M, Bafekry A, Gogova D, Hoat DM, Ghergherehchi M, Chuong NV, Feghhi SAH. Novel two-dimensional ZnO2, CdO2 and HgO2 monolayers: a first-principles-based prediction. NEW J CHEM 2021. [DOI: 10.1039/d1nj01610e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In this paper, the existence of monolayers with the chemical formula XO2, where X = Zn, Cd, and Hg with hexagonal and tetragonal lattice structures is theoretically predicted by means of first principles calculations.
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Affiliation(s)
- M. Faraji
- Micro and Nanotechnology Graduate Program
- TOBB University of Economics and Technology
- Ankara
- Turkey
| | - A. Bafekry
- Department of Radiation Application
- Shahid Beheshti University
- Tehran 1983969411
- Iran
- Department of Physics, University of Antwerp
| | - D. Gogova
- Department of Physics
- University of Oslo
- Blindern
- Norway
| | - D. M. Hoat
- Institute of Theoretical and Applied Research
- Duy Tan University
- Hanoi 100000
- Vietnam
- Faculty of Natural Sciences
| | - M. Ghergherehchi
- College of Electronic and Electrical Engineering
- Sungkyunkwan University
- Suwon
- Korea
| | - N. V. Chuong
- Department of Materials Science and Engineering
- Le Quy Don Technical University
- Hanoi 100000
- Vietnam
| | - S. A. H. Feghhi
- Department of Radiation Application
- Shahid Beheshti University
- Tehran 1983969411
- Iran
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8
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Zhao H, Vomiero A, Rosei F. Tailoring the Heterostructure of Colloidal Quantum Dots for Ratiometric Optical Nanothermometry. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2000804. [PMID: 32468691 DOI: 10.1002/smll.202000804] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 04/15/2020] [Indexed: 05/27/2023]
Abstract
Colloidal quantum dots (QDs) are a fascinating class of semiconducting nanocrystals, thanks to their optical properties tunable through size and composition, and simple synthesis methods. Recently, colloidal double-emission QDs have been successfully applied as competitive optical temperature sensors, since they exhibit structure-tunable double emission, temperature-dependent photoluminescence, high quantum yield, and excellent photostability. Until now, QDs have been used as nanothermometers for in vivo biological thermal imaging, and thermal mapping in complex environments at the sub-microscale to nanoscale range. In this Review, recent progress for QD-based nanothermometers is highlighted and perspectives for future work are described.
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Affiliation(s)
- Haiguang Zhao
- State Key Laboratory of Bio-Fibers and Eco-Textiles, Qingdao University, No. 308 Ningxia Road, Qingdao, 266071, P. R. China
- College of Physics, University-Industry Joint Center for Ocean Observation and Broadband Communication, Qingdao University, Qingdao, 266071, P. R. China
| | - Alberto Vomiero
- Division of Materials Science, Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, 971 87, Sweden
- Department of Molecular Science and Nano Systems, Ca' Foscari University of Venice Via Torino 155, Venezia Mestre, 30172, Italy
| | - Federico Rosei
- Centre for Energy, Materials and Telecommunications, Institut National de la Recherche Scientifique, Université du Québec, 1650 Boulevard Lionel-Boulet, Varennes, Québec, J3X1S2, Canada
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9
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Miranti R, Shin D, Septianto RD, Ibáñez M, Kovalenko MV, Matsushita N, Iwasa Y, Bisri SZ. Exclusive Electron Transport in Core@Shell PbTe@PbS Colloidal Semiconductor Nanocrystal Assemblies. ACS NANO 2020; 14:3242-3250. [PMID: 32073817 DOI: 10.1021/acsnano.9b08687] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Assemblies of colloidal semiconductor nanocrystals (NCs) in the form of thin solid films leverage the size-dependent quantum confinement properties and the wet chemical methods vital for the development of the emerging solution-processable electronics, photonics, and optoelectronics technologies. The ability to control the charge carrier transport in the colloidal NC assemblies is fundamental for altering their electronic and optical properties for the desired applications. Here we demonstrate a strategy to render the solids of narrow-bandgap NC assemblies exclusively electron-transporting by creating a type-II heterojunction via shelling. Electronic transport of molecularly cross-linked PbTe@PbS core@shell NC assemblies is measured using both a conventional solid gate transistor and an electric-double-layer transistor, as well as compared with those of core-only PbTe NCs. In contrast to the ambipolar characteristics demonstrated by many narrow-bandgap NCs, the core@shell NCs exhibit exclusive n-type transport, i.e., drastically suppressed contribution of holes to the overall transport. The PbS shell that forms a type-II heterojunction assists the selective carrier transport by heavy doping of electrons into the PbTe-core conduction level and simultaneously strongly localizes the holes within the NC core valence level. This strongly enhanced n-type transport makes these core@shell NCs suitable for applications where ambipolar characteristics should be actively suppressed, in particular, for thermoelectric and electron-transporting layers in photovoltaic devices.
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Affiliation(s)
- Retno Miranti
- Department of Materials Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8550, Japan
| | - Daiki Shin
- Quantum Phase Electronic Center (QPEC) and Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Ricky Dwi Septianto
- Department of Materials Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8550, Japan
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Maria Ibáñez
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir Prelog Weg 1, Zurich 8093, Switzerland
- EMPA-Swiss Federal Laboratories for Materials Science and Technology, Uberlandstrasse 129, Dubendorf 8600, Switzerland
| | - Maksym V Kovalenko
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir Prelog Weg 1, Zurich 8093, Switzerland
- EMPA-Swiss Federal Laboratories for Materials Science and Technology, Uberlandstrasse 129, Dubendorf 8600, Switzerland
| | - Nobuhiro Matsushita
- Department of Materials Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8550, Japan
| | - Yoshihiro Iwasa
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Quantum Phase Electronic Center (QPEC) and Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Satria Zulkarnaen Bisri
- Department of Materials Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8550, Japan
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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10
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Cassidy J, Zamkov M. Nanoshell quantum dots: Quantum confinement beyond the exciton Bohr radius. J Chem Phys 2020; 152:110902. [PMID: 32199442 DOI: 10.1063/1.5126423] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Nanoshell quantum dots (QDs) represent a novel class of colloidal semiconductor nanocrystals (NCs), which supports tunable optoelectronic properties over the extended range of particle sizes. Traditionally, the ability to control the bandgap of colloidal semiconductor NCs is limited to small-size nanostructures, where photoinduced charges are confined by Coulomb interactions. A notorious drawback of such a restricted size range concerns the fact that assemblies of smaller nanoparticles tend to exhibit a greater density of interfacial and surface defects. This presents a potential problem for device applications of semiconductor NCs where the charge transport across nanoparticle films is important, as in the case of solar cells, field-effect transistors, and photoelectrochemical devices. The morphology of nanoshell QDs addresses this issue by enabling the quantum-confinement in the shell layer, where two-dimensional excitons can exist, regardless of the total particle size. Such a geometry exhibits one of the lowest surface-to-volume ratios among existing QD architectures and, therefore, could potentially lead to improved charge-transport and multi-exciton characteristics. The expected benefits of the nanoshell architecture were recently demonstrated by a number of reports on the CdSbulk/CdSe nanoshell model system, showing an improved photoconductivity of solids and increased lifetime of multi-exciton populations. Along these lines, this perspective will summarize the recent work on CdSbulk/CdSe nanoshell colloids and discuss the possibility of employing other nanoshell semiconductor combinations in light-harvesting and lasing applications.
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Affiliation(s)
- James Cassidy
- The Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, USA
| | - Mikhail Zamkov
- The Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, USA
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11
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Pinchetti V, Shornikova EV, Qiang G, Bae WK, Meinardi F, Crooker SA, Yakovlev DR, Bayer M, Klimov VI, Brovelli S. Dual-Emitting Dot-in-Bulk CdSe/CdS Nanocrystals with Highly Emissive Core- and Shell-Based Trions Sharing the Same Resident Electron. NANO LETTERS 2019; 19:8846-8854. [PMID: 31651177 DOI: 10.1021/acs.nanolett.9b03676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Colloidal CdSe nanocrystals (NCs) overcoated with an ultrathick CdS shell, also known as dot-in-bulk (DiB) structures, can support two types of excitons, one of which is core-localized and the other, shell-localized. In the case of weak "sub-single-exciton" pumping, emission alternates between the core- and shell-related channels, which leads to two-color light. This property makes these structures uniquely suited for a variety of photonic applications as well as ideal model systems for realizing complex excitonic quasi-particles that do not occur in conventional core/shell NCs. Here, we show that the DiB design can enable an unusual regime in which the same long-lived resident electron can endow trionlike characteristics to either of the two excitons of the DiB NC (core- or shell-based). These two spectrally distinct trion states are apparent in the measured photoluminescence (PL) and spin dynamics of core and shell excitons conducted over a wide range of temperatures and applied magnetic fields. Low-temperature PL measurements indicate that core- and shell-based trions are characterized by a nearly ideal (∼100%) emission quantum yield, suggesting the strong suppression of Auger recombination for both types of excitations. Polarization-resolved PL experiments in magnetic fields of up to 60 T reveal that the core- and the shell-localized trions exhibit remarkably similar spin dynamics, which in both cases are controlled by spin-flip processes involving a heavy hole.
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Affiliation(s)
- Valerio Pinchetti
- Dipartimento di Scienza dei Materiali , Università degli Studi di Milano-Bicocca , via Roberto Cozzi 55 , I-20125 Milano , Italy
| | - Elena V Shornikova
- Experimentelle Physik 2 , Technische Universität Dortmund , 44227 Dortmund , Germany
| | - Gang Qiang
- Experimentelle Physik 2 , Technische Universität Dortmund , 44227 Dortmund , Germany
| | - Wan Ki Bae
- Chemistry Division , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Francesco Meinardi
- Dipartimento di Scienza dei Materiali , Università degli Studi di Milano-Bicocca , via Roberto Cozzi 55 , I-20125 Milano , Italy
| | - Scott A Crooker
- National High Magnetic Field Laboratory , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Dmitri R Yakovlev
- Experimentelle Physik 2 , Technische Universität Dortmund , 44227 Dortmund , Germany
- Ioffe Institute, Russian Academy of Sciences , 194021 St. Petersburg , Russia
| | - Manfred Bayer
- Experimentelle Physik 2 , Technische Universität Dortmund , 44227 Dortmund , Germany
- Ioffe Institute, Russian Academy of Sciences , 194021 St. Petersburg , Russia
| | - Victor I Klimov
- Chemistry Division , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Sergio Brovelli
- Dipartimento di Scienza dei Materiali , Università degli Studi di Milano-Bicocca , via Roberto Cozzi 55 , I-20125 Milano , Italy
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12
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van der Stam W, Grimaldi G, Geuchies JJ, Gudjonsdottir S, van Uffelen PT, van Overeem M, Brynjarsson B, Kirkwood N, Houtepen AJ. Electrochemical Modulation of the Photophysics of Surface-Localized Trap States in Core/Shell/(Shell) Quantum Dot Films. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2019; 31:8484-8493. [PMID: 31666761 PMCID: PMC6814269 DOI: 10.1021/acs.chemmater.9b02908] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 09/23/2019] [Indexed: 05/03/2023]
Abstract
In this work, we systematically study the spectroelectrochemical response of CdSe quantum dots (QDs), CdSe/CdS core/shell QDs with varying CdS shell thicknesses, and CdSe/CdS/ZnS core/shell/shell QDs in order to elucidate the influence of localized surface trap states on the optoelectronic properties. By correlating the differential absorbance and the photoluminescence upon electrochemically raising the Fermi level, we reveal that trap states near the conduction band (CB) edge give rise to nonradiative recombination pathways regardless of the CdS shell thickness, evidenced by quenching of the photoluminescence before the CB edge is populated with electrons. This points in the direction of shallow trap states localized on the CdS shell surface that give rise to nonradiative recombination pathways. We suggest that these shallow trap states reduce the quantum yield because of enhanced hole trapping when the Fermi level is raised electrochemically. We show that these shallow trap states are removed when additional wide band gap ZnS shells are grown around the CdSe/CdS core/shell QDs.
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13
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Liu B, Sharma M, Yu J, Shendre S, Hettiarachchi C, Sharma A, Yeltik A, Wang L, Sun H, Dang C, Demir HV. Light-Emitting Diodes with Cu-Doped Colloidal Quantum Wells: From Ultrapure Green, Tunable Dual-Emission to White Light. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1901983. [PMID: 31379086 DOI: 10.1002/smll.201901983] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 06/28/2019] [Indexed: 06/10/2023]
Abstract
Copper-doped colloidal quantum wells (Cu-CQWs) are considered a new class of optoelectronic materials. To date, the electroluminescence (EL) property of Cu-CQWs has not been revealed. Additionally, it is desirable to achieve ultrapure green, tunable dual-emission and white light to satisfy the various requirement of display and lighting applications. Herein, light-emitting diodes (LEDs) based on colloidal Cu-CQWs are demonstrated. For the 0% Cu-doped concentration, the LED exhibits Commission Internationale de L'Eclairage 1931 coordinates of (0.103, 0.797) with a narrow EL full-wavelength at half-maximum of 12 nm. For the 0.5% Cu-doped concentration, a dual-emission LED is realized. Remarkably, the dual emission can be tuned by manipulating the device engineering. Furthermore, at a high doping concentration of 2.4%, a white LED based on CQWs is developed. With the management of doping concentrations, the color tuning (green, dual-emission to white) is shown. The findings not only show that LEDs with CQWs can exhibit polychromatic emission but also unlock a new direction to develop LEDs by exploiting 2D impurity-doped CQWs that can be further extended to the application of other impurities (e.g., Mn, Ag).
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Affiliation(s)
- Baiquan Liu
- Luminous! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering and School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 639798, Singapore
| | - Manoj Sharma
- Luminous! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering and School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 639798, Singapore
| | - Junhong Yu
- Luminous! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering and School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 639798, Singapore
| | - Sushant Shendre
- Luminous! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering and School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 639798, Singapore
| | - Chathuranga Hettiarachchi
- Centre for OptoElectronics and Biophotonics (COEB), School of Electrical and Electronic Engineering, The Photonics Institute (TPI), Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Ashma Sharma
- Luminous! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering and School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 639798, Singapore
| | - Aydan Yeltik
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, 06800, Turkey
| | - Lin Wang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Handong Sun
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Cuong Dang
- Luminous! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering and School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 639798, Singapore
- Centre for OptoElectronics and Biophotonics (COEB), School of Electrical and Electronic Engineering, The Photonics Institute (TPI), Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Hilmi Volkan Demir
- Luminous! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering and School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 639798, Singapore
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, 06800, Turkey
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14
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Lin ML, Miscuglio M, Polovitsyn A, Leng YC, Martín-García B, Moreels I, Tan PH, Krahne R. Giant-Shell CdSe/CdS Nanocrystals: Exciton Coupling to Shell Phonons Investigated by Resonant Raman Spectroscopy. J Phys Chem Lett 2019; 10:399-405. [PMID: 30626187 DOI: 10.1021/acs.jpclett.8b03211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The interaction between excitons and phonons in semiconductor nanocrystals plays a crucial role in the exciton energy spectrum and dynamics, and thus in their optical properties. We investigate the exciton-phonon coupling in giant-shell CdSe/CdS core-shell nanocrystals via resonant Raman spectroscopy. The Huang-Rhys parameter is evaluated by the intensity ratio of the longitudinal-optical (LO) phonon of CdS with its first multiscattering (2LO) replica. We used four different excitation wavelengths in the range from the onset of the CdS shell absorption to well above the CdS shell band edge to get insight into resonance effects of the CdS LO phonon with high-energy excitonic transitions. The isotropic spherical giant-shell nanocrystals show consistently stronger exciton-phonon coupling as compared to the anisotropic rod-shaped dot-in-rod (DiR) architecture, and the 2LO/LO intensity ratio decreases for excitation wavelengths approaching the CdS band edge. The strong exciton-phonon coupling in the spherical giant-shell nanocrystals can be related to the delocalization of the electronic wave functions. Furthermore, we observe the radial breathing modes of the GS nanocrystals and their overtones by ultralow frequency Raman spectroscopy with nonresonant excitation, using laser energies well below the band gap of the heteronanocrystals, and highlight the differences between higher-order optical and acoustic phonon modes.
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Affiliation(s)
- Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures , Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083 , China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation , University of Chinese Academy of Sciences , Beijing 100190 , China
| | - Mario Miscuglio
- Istituto Italiano di Tecnologia (IIT) , Via Morego 30 , 16163 Genoa , Italy
| | - Anatolii Polovitsyn
- Department of Chemistry , Ghent University , Krijgslaan 281-S3 , 9000 Gent , Belgium
| | - Yu-Chen Leng
- State Key Laboratory of Superlattices and Microstructures , Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083 , China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation , University of Chinese Academy of Sciences , Beijing 100190 , China
| | | | - Iwan Moreels
- Department of Chemistry , Ghent University , Krijgslaan 281-S3 , 9000 Gent , Belgium
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures , Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083 , China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation , University of Chinese Academy of Sciences , Beijing 100190 , China
| | - Roman Krahne
- Istituto Italiano di Tecnologia (IIT) , Via Morego 30 , 16163 Genoa , Italy
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15
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Nandan Y, Mehata MS. Wavefunction Engineering of Type-I/Type-II Excitons of CdSe/CdS Core-Shell Quantum Dots. Sci Rep 2019; 9:2. [PMID: 30626883 PMCID: PMC6327053 DOI: 10.1038/s41598-018-37676-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 12/13/2018] [Indexed: 11/10/2022] Open
Abstract
Nanostructured semiconductors have the unique shape/size-dependent band gap tunability, which has various applications. The quantum confinement effect allows controlling the spatial distribution of the charge carriers in the core-shell quantum dots (QDs). Upon increasing shell thickness (e.g., from 0.25-3.25 nm) of core-shell QDs, the radial distribution function (RDF) of hole shifts towards the shell suggesting the confinement region switched from Type-I to Type-II excitons. As a result, there is a jump in the transition energy towards the higher side (blue shift). However, an intermediate state appeared as pseudo Type II excitons, in which holes are co-localized in the shell as well core whereas electrons are confined in core only, resulting in a dual absorption band (excitation energy), carried out by the analysis of the overlap percentage using the Hartree-Fock method. The findings are a close approximation to the experimental evidences. Thus, the understanding of the motion of e-h in core-shell QDs is essential for photovoltaic, LEDs, etc.
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Affiliation(s)
- Yashaswi Nandan
- Laser-Spectroscopy Laboratory, Department of Applied Physics, Delhi Technological University, Bawana Road, Delhi, 110042, India
| | - Mohan Singh Mehata
- Laser-Spectroscopy Laboratory, Department of Applied Physics, Delhi Technological University, Bawana Road, Delhi, 110042, India.
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16
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Bisschop S, Geiregat P, Aubert T, Hens Z. The Impact of Core/Shell Sizes on the Optical Gain Characteristics of CdSe/CdS Quantum Dots. ACS NANO 2018; 12:9011-9021. [PMID: 30193059 DOI: 10.1021/acsnano.8b02493] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Colloidal quantum dots (QDs) are highly attractive as the active material for optical amplifiers and lasers. Here, we address the relation between the structure of CdSe/CdS core/shell QDs, the material gain they can deliver, and the threshold needed to attain net stimulated emission by optical pumping. On the basis of an initial gain model, we predict that reducing the thickness of the CdS shell grown around a given CdSe core will increase the maximal material gain, while increasing the shell thickness will lower the gain threshold. We assess this trade-off by means of transient absorption spectroscopy. Our results confirm that thin-shell QDs exhibit the highest material gain. In quantitative agreement with the model, core and shell sizes hugely impact on the material gain, which ranges from 2800 cm-1 for large core/thin shell QDs to less than 250 cm-1 for small core/thick shell QDs. On the other hand, the significant threshold reduction expected for thick-shell QDs is absent. We relate this discrepancy between model and experiment to a transition from attractive to repulsive exciton-exciton interactions with increasing shell thickness. The spectral blue-shift that comes with exciton-exciton repulsion leads to competition between stimulated emission and higher energy absorbing transitions, which raises the gain threshold. As a result, small-core/thick-shell QDs need up to 3.7 excitations per QD to reach transparency, whereas large-core/thin shell QDs only need 1.0, a number often seen as a hard limit for biexciton-mediated optical gain. This makes large-core/thin-shell QDs that feature attractive exciton-exciton interactions the overall champion core/shell configuration in view of highest material gain, lowest threshold exciton occupation, and longest gain lifetime.
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Affiliation(s)
- Suzanne Bisschop
- Physics and Chemistry of Nanostructures , Ghent University , 9000 Ghent , Belgium
- Center for Nano and Biophotonics (NB Photonics) , Ghent University , 9000 Ghent , Belgium
| | - Pieter Geiregat
- Physics and Chemistry of Nanostructures , Ghent University , 9000 Ghent , Belgium
- Center for Nano and Biophotonics (NB Photonics) , Ghent University , 9000 Ghent , Belgium
| | - Tangi Aubert
- Physics and Chemistry of Nanostructures , Ghent University , 9000 Ghent , Belgium
- Center for Nano and Biophotonics (NB Photonics) , Ghent University , 9000 Ghent , Belgium
| | - Zeger Hens
- Physics and Chemistry of Nanostructures , Ghent University , 9000 Ghent , Belgium
- Center for Nano and Biophotonics (NB Photonics) , Ghent University , 9000 Ghent , Belgium
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17
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Wieliczka BM, Kaledin AL, Buhro WE, Loomis RA. Wave Function Engineering in CdSe/PbS Core/Shell Quantum Dots. ACS NANO 2018; 12:5539-5550. [PMID: 29787230 DOI: 10.1021/acsnano.8b01248] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The synthesis of epitaxial CdSe/PbS core/shell quantum dots (QDs) is reported. The PbS shell grows in a rock salt structure on the zinc blende CdSe core, thereby creating a crystal structure mismatch through additive growth. Absorption and photoluminescence (PL) band edge features shift to lower energies with increasing shell thickness, but remain above the CdSe bulk band gap. Nevertheless, the profiles of the absorption spectra vary with shell growth, indicating that the overlap of the electron and hole wave functions is changing significantly. This leads to over an order of magnitude reduction of absorption near the band gap and a large, tunable energy shift, of up to 550 meV, between the onset of strong absorption and the band edge PL. While the bulk valence and conduction bands adopt an inverse type-I alignment, the observed spectroscopic behavior is consistent with a transition between quasi-type-I and quasi-type-II behavior depending on shell thickness. Three effective mass approximation models support this hypothesis and suggest that the large difference in effective masses between the core and shell results in hole localization in the CdSe core and a delocalization of the electron across the entire QD. These results show the tuning of wave functions and transition energies in CdSe/PbS nanoheterostructures with prospects for use in optoelectronic devices for luminescent solar concentration or multiexciton generation.
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Affiliation(s)
- Brian M Wieliczka
- Department of Chemistry and Institute of Materials Science and Engineering , Washington University in St. Louis , One Brookings Drive, CB 1134 , Saint Louis , Missouri 63130 , United States
| | - Alexey L Kaledin
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation , Emory University , Atlanta , Georgia 30322 , United States
| | - William E Buhro
- Department of Chemistry and Institute of Materials Science and Engineering , Washington University in St. Louis , One Brookings Drive, CB 1134 , Saint Louis , Missouri 63130 , United States
| | - Richard A Loomis
- Department of Chemistry and Institute of Materials Science and Engineering , Washington University in St. Louis , One Brookings Drive, CB 1134 , Saint Louis , Missouri 63130 , United States
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18
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Selvaraj J, Mahesh A, Baskaralingam V, Dhayalan A, Paramasivam T. Colloidal Gradated Alloyed (Cu)ZnInS/ZnS Core/Shell Nanocrystals with Tunable Optical Properties for Live Cell Optical Imaging. ChemistrySelect 2018. [DOI: 10.1002/slct.201800742] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Joicy Selvaraj
- Centre for Nanoscience and TechnologyPondicherry University Puducherry - 605 014 India
| | - Arun Mahesh
- Department of BiotechnologyPondicherry University Puducherry - 605 014 India
| | - Vaseeharan Baskaralingam
- Department of Animal Health and ManagementAlagappa University Karaikudi – 630 003, Tamil Nadu India
| | - Arunkumar Dhayalan
- Department of BiotechnologyPondicherry University Puducherry - 605 014 India
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19
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le Feber B, Prins F, De Leo E, Rabouw FT, Norris DJ. Colloidal-Quantum-Dot Ring Lasers with Active Color Control. NANO LETTERS 2018; 18:1028-1034. [PMID: 29283266 PMCID: PMC5817622 DOI: 10.1021/acs.nanolett.7b04495] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Revised: 12/15/2017] [Indexed: 05/03/2023]
Abstract
To improve the photophysical performance of colloidal quantum dots for laser applications, sophisticated core/shell geometries have been developed. Typically, a wider bandgap semiconductor is added as a shell to enhance the gain from the quantum-dot core. This shell is designed to electronically isolate the core, funnel excitons to it, and reduce nonradiative Auger recombination. However, the shell could also potentially provide a secondary source of gain, leading to further versatility in these materials. Here we develop high-quality quantum-dot ring lasers that not only exhibit lasing from both the core and the shell but also the ability to switch between them. We fabricate ring resonators (with quality factors up to ∼2500) consisting only of CdSe/CdS/ZnS core/shell/shell quantum dots using a simple template-stripping process. We then examine lasing as a function of the optical excitation power and ring radius. In resonators with quality factors >1000, excitons in the CdSe cores lead to red lasing with thresholds at ∼25 μJ/cm2. With increasing power, green lasing from the CdS shell emerges (>100 μJ/cm2) and then the red lasing begins to disappear (>250 μJ/cm2). We present a rate-equation model that can explain this color switching as a competition between exciton localization into the core and stimulated emission from excitons in the shell. Moreover, by lowering the quality factor of the cavity we can engineer the device to exhibit only green lasing. The mechanism demonstrated here provides a potential route toward color-switchable quantum-dot lasers.
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Affiliation(s)
- Boris le Feber
- Optical Materials Engineering Laboratory,
Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | | | - Eva De Leo
- Optical Materials Engineering Laboratory,
Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | - Freddy T. Rabouw
- Optical Materials Engineering Laboratory,
Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | - David J. Norris
- Optical Materials Engineering Laboratory,
Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
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20
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Wang Y, Ta VD, Leck KS, Tan BHI, Wang Z, He T, Ohl CD, Demir HV, Sun H. Robust Whispering-Gallery-Mode Microbubble Lasers from Colloidal Quantum Dots. NANO LETTERS 2017; 17:2640-2646. [PMID: 28288279 DOI: 10.1021/acs.nanolett.7b00447] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Microlasers hold great promise for the development of photonics and optoelectronics. Among the discovered optical gain materials, colloidal quantum dots (CQDs) have been recognized as the most appealing candidate due to the facile emission tunability and solution processability. However, to date, it is still challenging to develop CQD-based microlasers with low cost yet high performance. Moreover, the poor long-term stability of CQDs remains to be the most critical issue, which may block their laser aspirations. Herein, we developed a unique but generic approach to forming a novel type of a whispering-gallery-mode (WGM) microbubble laser from the hybrid CQD/poly(methyl methacrylate) (PMMA) nanocomposites. The formation mechanism of the microbubbles was unraveled by recording the drying process of the nanocomposite droplets. Interestingly, these microbubbles naturally serve as the high-quality WGM laser resonators. By simply changing the CQDs, the lasing emission can be tuned across the whole visible spectral range. Importantly, these microbubble lasers exhibit unprecedented long-term stability (over one year), sufficient for practical applications. As a proof-of-concept, the potential of water vapor sensing was demonstrated. Our results represent a significant advance in microlasers based on the advantageous CQDs and may offer new possibilities for photonics and optoelectronics.
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Affiliation(s)
| | - Van Duong Ta
- Department of Physics, King's College London , Strand, London, WC2R 2LS, United Kingdom
| | - Kheng Swee Leck
- School of Electrical and Electronic Engineering, Luminous! Center of Excellence for Semiconductor Lighting and Displays, Nanyang Technological University , Nanyang Avenue, Singapore 639798, Singapore
| | | | | | - Tingchao He
- College of Physics Science and Technology, Shenzhen University , Shenzhen 518060, China
| | | | - Hilmi Volkan Demir
- School of Electrical and Electronic Engineering, Luminous! Center of Excellence for Semiconductor Lighting and Displays, Nanyang Technological University , Nanyang Avenue, Singapore 639798, Singapore
- Department of Electrical and Electronics Engineering, Department of Physics, and UNAM-National Nanotechnology Research Center, Bilkent University , Bilkent, Ankara 06800, Turkey
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21
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Lorenzon M, Pinchetti V, Bruni F, Bae WK, Meinardi F, Klimov VI, Brovelli S. Single-Particle Ratiometric Pressure Sensing Based on "Double-Sensor" Colloidal Nanocrystals. NANO LETTERS 2017; 17:1071-1081. [PMID: 28032501 DOI: 10.1021/acs.nanolett.6b04577] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Ratiometric pressure sensitive paints (r-PSPs) are all-optical probes for monitoring oxygen flows in the vicinity of complex or miniaturized surfaces. They typically consist of a porous binder embedding mixtures of a reference and a sensor chromophore exhibiting oxygen-insensitive and oxygen-responsive luminescence, respectively. Here, we demonstrate the first example of an r-PSP based on a single two-color emitter that removes limitations of r-PSPs based on chromophore mixtures such as different temperature dependencies of the two chromophores, cross-readout between the reference and sensor signals and phase segregation. In our approach, we utilize a novel "double-sensor" r-PSP that features two spectrally separated emission bands with opposite responses to the O2 pressure, which boosts the sensitivity with respect to traditional reference-sensor pairs. Specifically, we use two-color-emitting dot-in-bulk CdSe/CdS core/shell nanocrystals, exhibiting red and green emission bands from their core and shell states, whose intensities are respectively enhanced and quenched in response to the increased oxygen partial pressure that effectively tunes the position of the nanocrystal's Fermi energy. This leads to a strong and reversible ratiometric response at the single particle level and an over 100% enhancement in the pressure sensitivity. Our proof-of-concept r-PSPs further exhibit suppressed cross-readout thanks to zero spectral overlap between the core and shell luminescence bands and a temperature-independent ratiometric response between 0 and 70 °C.
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Affiliation(s)
- Monica Lorenzon
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca , via Cozzi 55, I 20125 Milano, Italy
| | - Valerio Pinchetti
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca , via Cozzi 55, I 20125 Milano, Italy
| | - Francesco Bruni
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca , via Cozzi 55, I 20125 Milano, Italy
| | - Wan Ki Bae
- Chemistry Division and Center for Advanced Solar Photophysics, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Francesco Meinardi
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca , via Cozzi 55, I 20125 Milano, Italy
| | - Victor I Klimov
- Chemistry Division and Center for Advanced Solar Photophysics, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Sergio Brovelli
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca , via Cozzi 55, I 20125 Milano, Italy
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22
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Gong K, Kelley DF, Kelley AM. Nonuniform Excitonic Charge Distribution Enhances Exciton-Phonon Coupling in ZnSe/CdSe Alloyed Quantum Dots. J Phys Chem Lett 2017; 8:626-630. [PMID: 28107015 DOI: 10.1021/acs.jpclett.6b02944] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Zinc to cadmium cation exchange of ZnSe quantum dots has been used to produce a series of alloyed Zn1-xCdxSe quantum dots. As x increases and the lowest-energy exciton shifts to the red, the peak initially broadens and then sharpens as x approaches 1. Resonance Raman spectra obtained with excitation near the lowest excitonic absorption peak show a gradual shift of the longitudinal optical phonon peak from 251 cm-1 in pure ZnSe to 210 cm-1 in nearly pure CdSe with strong broadening at intermediate compositions. The LO overtone to fundamental intensity ratio, a rough gauge of exciton-phonon coupling strength, increases considerably for intermediate compositions compared with those of either pure ZnSe or pure CdSe. The results indicate that partial localization of the hole in locally Cd-rich regions of the alloyed particles increases the strengths of local internal electric fields, increasing the coupling between the exciton and polar optical phonons.
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Affiliation(s)
- Ke Gong
- Chemistry & Chemical Biology, University of California, Merced , 5200 North Lake Road, Merced, California 95343, United States
| | - David F Kelley
- Chemistry & Chemical Biology, University of California, Merced , 5200 North Lake Road, Merced, California 95343, United States
| | - Anne Myers Kelley
- Chemistry & Chemical Biology, University of California, Merced , 5200 North Lake Road, Merced, California 95343, United States
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23
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Chandrasekaran S, Ngo YLT, Sui L, Kim EJ, Dang DK, Chung JS, Hur SH. Highly enhanced visible light water splitting of CdS by green to blue upconversion. Dalton Trans 2017; 46:13912-13919. [DOI: 10.1039/c7dt02936e] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This paper reports a new class of visible light water splitting photocatalysts based on a triplet–triplet annihilation (TTA) upconversion (UC) process.
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Affiliation(s)
| | - Yen-Linh Thi Ngo
- School of Chemical Engineering
- University of Ulsan
- Ulsan 44610
- South Korea
| | - Lijun Sui
- School of Chemical Engineering
- University of Ulsan
- Ulsan 44610
- South Korea
| | - Eui Jung Kim
- School of Chemical Engineering
- University of Ulsan
- Ulsan 44610
- South Korea
| | - Dinh Khoi Dang
- School of Chemical Engineering
- University of Ulsan
- Ulsan 44610
- South Korea
| | - Jin Suk Chung
- School of Chemical Engineering
- University of Ulsan
- Ulsan 44610
- South Korea
| | - Seung Hyun Hur
- School of Chemical Engineering
- University of Ulsan
- Ulsan 44610
- South Korea
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24
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Makarov NS, Lin Q, Pietryga JM, Robel I, Klimov VI. Auger Up-Conversion of Low-Intensity Infrared Light in Engineered Quantum Dots. ACS NANO 2016; 10:10829-10841. [PMID: 27936587 DOI: 10.1021/acsnano.6b04928] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
One source of efficiency losses in photovoltaic cells is their transparency toward solar photons with energies below the band gap of the absorbing layer. This loss can be reduced using a process of up-conversion whereby two or more sub-band-gap photons generate a single above-gap exciton. Traditional approaches to up-conversion, such as nonlinear two-photon absorption (2PA) or triplet fusion, suffer from low efficiency at solar light intensities, a narrow absorption bandwidth, nonoptimal absorption energies, and difficulties for implementing in practical devices. Here we show that these deficiencies can be alleviated using the effect of Auger up-conversion in thick-shell PbSe/CdSe quantum dots. This process relies on Auger recombination whereby two low-energy, core-based excitons are converted into a single higher-energy, shell-based exciton. Compared to their monocomponent counterparts, the tailored PbSe/CdSe heterostructures feature enhanced absorption cross-sections, a higher efficiency of the "productive" Auger pathway involving re-excitation of a hole, and longer lifetimes of both core- and shell-localized excitons. These features lead to effective up-conversion cross-sections that are more than 6 orders of magnitude higher than for standard nonlinear 2PA, which allows for efficient up-conversion of continuous wave infrared light at intensities as low as a few watts per square centimeter.
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Affiliation(s)
- Nikolay S Makarov
- Center for Advanced Solar Photophysics, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Qianglu Lin
- Center for Advanced Solar Photophysics, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Jeffrey M Pietryga
- Center for Advanced Solar Photophysics, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - István Robel
- Center for Advanced Solar Photophysics, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Victor I Klimov
- Center for Advanced Solar Photophysics, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
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25
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Liao C, Xu R, Xu Y, Zhang C, Xiao M, Zhang L, Lu C, Cui Y, Zhang J. Ultralow-Threshold Single-Mode Lasing from Phase-Pure CdSe/CdS Core/Shell Quantum Dots. J Phys Chem Lett 2016; 7:4968-4976. [PMID: 27973873 DOI: 10.1021/acs.jpclett.6b02465] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The development of colloidal quantum dot (QD) lasers is blocked by Auger recombination (AR). Here, phase-pure wurtzite CdSe/CdS core/shell QDs with controlled shell thickness are reported, which possess nearly defect-free core/shell interfaces. Benefiting from increased volume, electron-hole partial spatial separation, and nearly defect-free alloyed interface, this series of QDs exhibit a greater than 3 orders of magnitude decrease in AR rates with increasing shell thickness. Consequently, the amplified spontaneous emission threshold of the QDs with an 11 monolayer CdS shell is found to reach a minimum of 16 μJ cm-2. A record long lifetime (>1000 ps) and extraordinarily large bandwidth (>170 nm) of optical gain are observed by employing ultrafast transient absorption spectroscopy. We leverage the low-threshold gain of the QDs to fabricate microlasers that display single-mode operation and an ultralow threshold of ∼2 μJ cm-2. Our results represent a valuable step toward practical QD lasers.
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Affiliation(s)
- Chen Liao
- Advanced Photonic Center, Southeast University , Nanjing 210096, China
| | - Ruilin Xu
- Advanced Photonic Center, Southeast University , Nanjing 210096, China
| | - Yanqing Xu
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University , Nanjing 210093, China
| | - Chunfeng Zhang
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University , Nanjing 210093, China
| | - Min Xiao
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University , Nanjing 210093, China
| | - Lei Zhang
- Advanced Photonic Center, Southeast University , Nanjing 210096, China
| | - Changgui Lu
- Advanced Photonic Center, Southeast University , Nanjing 210096, China
| | - Yiping Cui
- Advanced Photonic Center, Southeast University , Nanjing 210096, China
| | - Jiayu Zhang
- Advanced Photonic Center, Southeast University , Nanjing 210096, China
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