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Zhang Y, Du W, Liu X. Photophysics and its application in photon upconversion. NANOSCALE 2024; 16:2747-2764. [PMID: 38250819 DOI: 10.1039/d3nr05450k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
Photoluminescence (PL) upconversion is a phenomenon involving light-matter interaction, where the energy of the emitted photons is higher than that of the incident photons. PL upconversion has promising applications in optoelectronic devices, displays, photovoltaics, imaging, diagnosis and treatment. In this review, we summarize the mechanism of PL upconversion and ultrafast PL physical processes. In particular, we highlight the advances in laser cooling, biological imaging, volumetric displays and photonics.
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Affiliation(s)
- Yutong Zhang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenna Du
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinfeng Liu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China.
- University of Chinese Academy of Sciences, Beijing 100049, China
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2
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Mueller NS, Arul R, Kang G, Saunders AP, Johnson AC, Sánchez-Iglesias A, Hu S, Jakob LA, Bar-David J, de Nijs B, Liz-Marzán LM, Liu F, Baumberg JJ. Photoluminescence upconversion in monolayer WSe 2 activated by plasmonic cavities through resonant excitation of dark excitons. Nat Commun 2023; 14:5726. [PMID: 37714855 PMCID: PMC10504321 DOI: 10.1038/s41467-023-41401-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 09/04/2023] [Indexed: 09/17/2023] Open
Abstract
Anti-Stokes photoluminescence (PL) is light emission at a higher photon energy than the excitation, with applications in optical cooling, bioimaging, lasing, and quantum optics. Here, we show how plasmonic nano-cavities activate anti-Stokes PL in WSe2 monolayers through resonant excitation of a dark exciton at room temperature. The optical near-fields of the plasmonic cavities excite the out-of-plane transition dipole of the dark exciton, leading to light emission from the bright exciton at higher energy. Through statistical measurements on hundreds of plasmonic cavities, we show that coupling to the dark exciton leads to a near hundred-fold enhancement of the upconverted PL intensity. This is further corroborated by experiments in which the laser excitation wavelength is tuned across the dark exciton. We show that a precise nanoparticle geometry is key for a consistent enhancement, with decahedral nanoparticle shapes providing an efficient PL upconversion. Finally, we demonstrate a selective and reversible switching of the upconverted PL via electrochemical gating. Our work introduces the dark exciton as an excitation channel for anti-Stokes PL in WSe2 and paves the way for large-area substrates providing nanoscale optical cooling, anti-Stokes lasing, and radiative engineering of excitons.
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Affiliation(s)
- Niclas S Mueller
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK.
- Fritz Haber Institute of the Max Planck Society, 14195, Berlin, Germany.
| | - Rakesh Arul
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Gyeongwon Kang
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
- Department of Chemistry, Kangwon National University, Chuncheon, 24341, South Korea
| | - Ashley P Saunders
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Amalya C Johnson
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Ana Sánchez-Iglesias
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), Paseo de Miramón 194, Donostia-San Sebastián, 20014, Spain
- Centro de Física de Materiales, CSIC-UPV/EHU, Manuel Lardizabal Ibilbidea 5, Donostia-San Sebastián, 20018, Spain
| | - Shu Hu
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Lukas A Jakob
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Jonathan Bar-David
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Bart de Nijs
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Luis M Liz-Marzán
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), Paseo de Miramón 194, Donostia-San Sebastián, 20014, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, 48009, Spain
- Centro de Investigación Biomédica en Red, Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Donostia-San Sebastián, 20014, Spain
| | - Fang Liu
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Jeremy J Baumberg
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK.
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Xu KX, Zhou Z, Zhang J. Phonon-Assisted Upconversion Photoluminescence of a Self-Trapped Exciton in the Rb 2CuCl 3 Single Crystal. J Phys Chem Lett 2023; 14:32-37. [PMID: 36563108 DOI: 10.1021/acs.jpclett.2c03514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Phonon-assisted upconversion photoluminescence (UCPL) plays an important role in a wide range of fields such as optical refrigeration, sensitive optical thermometry, quantum state control, and upconversion optoelectronics. High photoluminescence quantum yield (PLQY) and strong electron-phonon coupling are two basic prerequisites of efficient UCPL materials. The self-trapped exciton (STE) system with the above-mentioned advantages hints that it may be a good candidate for phonon-assisted UCPL. Here, we synthesized Rb2CuCl3 single crystals (SCs) which yield a high PLQY of the STE emission at 400 nm, and an efficient phonon-assisted UCPL was demonstrated at room temperature. By exponentially fitting the intensity of temperature-dependent UCPL spectra, we obtained an optical thermometry sensitivity of SCs up to 6 mK at 295 K. We also propose that net cooling would be possible if the PLQY is improved up to 91.5% with 345 nm excitation. Our results open a new door to explore laser cooling in STE systems.
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Affiliation(s)
- Kai-Xuan Xu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ziren Zhou
- Key Laboratory for Ultrafine Materials of Ministry of Education, Shanghai Engineering Research Center of Hierarchical Nanomaterials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Jun Zhang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
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4
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Kuang Z, Yuan L, Peng Q, Wang J. Sub-Bandgap-Voltage Electroluminescence of Light-Emitting Diodes. J Phys Chem Lett 2022; 13:11925-11927. [PMID: 36579439 DOI: 10.1021/acs.jpclett.2c03530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Sub-bandgap-voltage electroluminescence (EL) has been frequently reported in quantum dot, organic, and perovskite light-emitting diodes. Due to the complex physical process across devices, the underlying mechanism is still under intensive debate. Here, based on thermodynamics, we offer an orthodox explanation of sub-bandgap-voltage EL and discuss the applicability of the previously proposed models.
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Affiliation(s)
- Zhiyuan Kuang
- Key Laboratory of Flexible Electronics (KLOFE), Institute of Advanced Materials (IAM), and School of Flexible Electronics (Future Technologies), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing211816, China
| | - Lingzhi Yuan
- Key Laboratory of Flexible Electronics (KLOFE), Institute of Advanced Materials (IAM), and School of Flexible Electronics (Future Technologies), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing211816, China
| | - Qiming Peng
- Key Laboratory of Flexible Electronics (KLOFE), Institute of Advanced Materials (IAM), and School of Flexible Electronics (Future Technologies), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing211816, China
| | - Jianpu Wang
- Key Laboratory of Flexible Electronics (KLOFE), Institute of Advanced Materials (IAM), and School of Flexible Electronics (Future Technologies), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing211816, China
- Strait Laboratory of Flexible Electronics (SLoFE), Fuzhou350117, China
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5
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Abstract
For a light-emitting diode (LED) to generate light, the minimum voltage required is widely considered to be the emitter’s bandgap divided by the elementary charge. Here we show for many classes of LEDs, including those based on perovskite, organic, quantum-dot and III–V semiconductors, light emission can be observed at record-low voltages of 36–60% of their bandgaps, exhibiting a large apparent energy gain of 0.6–1.4 eV per photon. For 17 types of LEDs with different modes of charge injection and recombination (dark saturation currents of ~10−39–10−15 mA cm−2), their emission intensity-voltage curves under low voltages show similar behaviours. These observations and their consistency with the diode simulations suggest the ultralow-voltage electroluminescence arises from a universal origin—the radiative recombination of non-thermal-equilibrium band-edge carriers whose populations are determined by the Fermi-Dirac function perturbed by a small external bias. These results indicate the potential of low-voltage LEDs for communications, computational and energy applications. Light emission from 17 types of LEDs is observed at record-low voltages of 36–60% of the bandgaps, which cannot be explained by earlier theories. The electroluminescence-voltage curves reveal a unified mechanism for ultralow-voltage LED operation.
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Wang Q, Wee ATS. Photoluminescence upconversion of 2D materials and applications. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:223001. [PMID: 33784662 DOI: 10.1088/1361-648x/abf37f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/30/2021] [Indexed: 06/12/2023]
Abstract
Photoluminescence (PL) upconversion is a phenomenon involving light-matter interactions, where the energy of emitted photons is higher than that of the incident photons. PL upconversion is an intriguing process in two-dimensional materials and specifically designed 2D heterostructures, which have potential upconversion applications in optoelectronic devices, bioimaging, and semiconductor cooling. In this review, we focus on the recent advances in photoluminescence upconversion in two-dimensional materials and their heterostructures. We discuss the upconversion mechanisms, applications, and future outlook of upconversion in two-dimensional materials.
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Affiliation(s)
- Qixing Wang
- Max Planck Institute for Solid State Research, Stuttgart D-70569, Germany
| | - Andrew T S Wee
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117551, Singapore
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Singh R, Liu W, Lim J, Robel I, Klimov VI. Hot-electron dynamics in quantum dots manipulated by spin-exchange Auger interactions. NATURE NANOTECHNOLOGY 2019; 14:1035-1041. [PMID: 31591527 DOI: 10.1038/s41565-019-0548-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 08/22/2019] [Indexed: 06/10/2023]
Abstract
The ability to effectively manipulate non-equilibrium 'hot' carriers could enable novel schemes for highly efficient energy harvesting and interconversion. In the case of semiconductor materials, realization of such hot-carrier schemes is complicated by extremely fast intraband cooling (picosecond to subpicosecond time scales) due to processes such as phonon emission. Here we show that using magnetically doped colloidal semiconductor quantum dots we can achieve extremely fast rates of spin-exchange processes that allow for 'uphill' energy transfer with an energy-gain rate that greatly exceeds the intraband cooling rate. This represents a dramatic departure from the usual situation where energy-dissipation via phonon emission outpaces energy gains due to standard Auger-type energy transfer at least by a factor of three. A highly favourable energy gain/loss rate ratio realized in magnetically doped quantum dots can enable effective schemes for capturing kinetic energy of hot, unrelaxed carriers via processes such as spin-exchange-mediated carrier multiplication and upconversion, hot-carrier extraction and electron photoemission.
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Affiliation(s)
- Rohan Singh
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Wenyong Liu
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Jaehoon Lim
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA
- Department of Chemical Engineering, Ajou University, Suwon, Republic of Korea
- Department of Energy System Research, Ajou University, Suwon, Republic of Korea
| | - István Robel
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Victor I Klimov
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
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8
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Wang Q, Zhang Q, Zhao X, Zheng YJ, Wang J, Luo X, Dan J, Zhu R, Liang Q, Zhang L, Wong PKJ, He X, Huang YL, Wang X, Pennycook SJ, Eda G, Wee ATS. High-Energy Gain Upconversion in Monolayer Tungsten Disulfide Photodetectors. NANO LETTERS 2019; 19:5595-5603. [PMID: 31241969 DOI: 10.1021/acs.nanolett.9b02136] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Photodetectors usually operate in the wavelength range with photon energy above the bandgap of channel semiconductors so that incident photons can excite electrons from valence band to conduction band to generate photocurrent. Here, however, we show that monolayer WS2 photodetectors can detect photons with energy even lying 219 meV below the bandgap of WS2 at room temperature. With the increase of excitation wavelength from 620 to 680 nm, photoresponsivity varies from 551 to 59 mA/W. This anomalous phenomenon is ascribed to energy upconversion, which is a combination effect of one-photon excitation and multiphonon absorption through an intermediate state created most likely by sulfur divacancy with oxygen adsorption. These findings will arouse research interests on other upconversion optoelectronic devices, photovoltaic devices, for example, of monolayer transition metal dichalcogenides (TMDCs).
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Affiliation(s)
- Qixing Wang
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
| | - Qi Zhang
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
| | - Xiaoxu Zhao
- Department of Materials Science and Engineering , National University of Singapore , 9 Engineering Drive 1 , Singapore 117575 , Singapore
| | - Yu Jie Zheng
- MOE Key Laboratory of Low-grade Energy Utilization Technologies and Systems , CQU-NUS Renewable Energy Materials and Devices Joint Laboratory , Chongqing 400044 , China
- School of Energy and Power Engineering , Chongqing University , Chongqing 400044 , China
| | - Junyong Wang
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
| | - Xin Luo
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics , Sun Yat-sen University , Guangzhou 12 510275 , Guangdong , People's Republic of China
| | - Jiadong Dan
- Department of Materials Science and Engineering , National University of Singapore , 9 Engineering Drive 1 , Singapore 117575 , Singapore
| | - Rui Zhu
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
| | - Qijie Liang
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
- SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering , Shenzhen University , Shenzhen 518060 , China
| | - Lei Zhang
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
| | - P K Johnny Wong
- Centre for Advanced 2D Materials , National University of Singapore , Block S14, 6 Science Drive 2 , Singapore 117546 , Singapore
| | - Xiaoyue He
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
| | - Yu Li Huang
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
| | - Xinyun Wang
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
- Centre for Advanced 2D Materials , National University of Singapore , Block S14, 6 Science Drive 2 , Singapore 117546 , Singapore
| | - Stephen J Pennycook
- Department of Materials Science and Engineering , National University of Singapore , 9 Engineering Drive 1 , Singapore 117575 , Singapore
| | - Goki Eda
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , 117543 , Singapore
- Centre for Advanced 2D Materials , National University of Singapore , Block S14, 6 Science Drive 2 , Singapore 117546 , Singapore
| | - Andrew T S Wee
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
- Centre for Advanced 2D Materials , National University of Singapore , Block S14, 6 Science Drive 2 , Singapore 117546 , Singapore
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Cai P, Huang Y, Seo HJ. Anti-Stokes Ultraviolet Luminescence and Exciton Detrapping in the Two-Dimensional Perovskite (C 6H 5C 2H 4NH 3) 2PbCl 4. J Phys Chem Lett 2019; 10:4095-4102. [PMID: 31274329 DOI: 10.1021/acs.jpclett.9b01604] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Recently, it has been found that low-dimensional organometallic halide perovskites can be adopted as nonlinear monolayer emitters because of their efficient spontaneous anti-Stokes visual luminescence under visual or near-infrared laser excitation. Herein, we demonstrate a luminescence up-conversion process from the visible self-trapped exciton (STE) to an ultraviolet (UV) free exciton (FE) in the two-dimensional perovskite (C6H5C2H4NH3)2PbCl4 quantum wells excited by nanosecond pulse laser excitation. An ultraviolet 347 nm near-band-edge FE emission is obtained under the excitation of 579 nm dye laser at 10 K by a two-step, two-photon absorption process from the real intermediate exciton state. In addition, the decay rise time of higher-laying states of STE indicates the excitonic detrapping procedure could occur by the annihilation of phonons. Our results suggest that the low-dimensional halide perovskites with deformable structure are able to be applied in visible light-pumped UV-emitting devices.
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Affiliation(s)
- Peiqing Cai
- College of Optical and Electronic Technology , China Jiliang University , Hangzhou , Zhejiang 310018 , China
| | - Yanlin Huang
- College of Chemistry, Chemical Engineering and Materials Science , Soochow University , Suzhou 215123 , China
| | - Hyo Jin Seo
- Department of Physics and Interdisciplinary Program of Biomedical, Mechanical and Electrical Engineering , Pukyong National University , Busan 608-737 , Republic of Korea
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Upconverted electroluminescence via Auger scattering of interlayer excitons in van der Waals heterostructures. Nat Commun 2019; 10:2335. [PMID: 31133651 PMCID: PMC6536535 DOI: 10.1038/s41467-019-10323-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 04/29/2019] [Indexed: 11/08/2022] Open
Abstract
The intriguing physics of carrier-carrier interactions, which likewise affect the operation of light emitting devices, stimulate the research on semiconductor structures at high densities of excited carriers, a limit reachable at large pumping rates or in systems with long-lived electron-hole pairs. By electrically injecting carriers into WSe2/MoS2 type-II heterostructures which are indirect in real and k-space, we establish a large population of typical optically silent interlayer excitons. Here, we reveal their emission spectra and show that the emission energy is tunable by an applied electric field. When the population is further increased by suppressing the radiative recombination rate with the introduction of an hBN spacer between WSe2 and MoS2, Auger-type and exciton-exciton annihilation processes become important. These processes are traced by the observation of an up-converted emission demonstrating that excitons gaining energy in non-radiative Auger processes can be recovered and recombine radiatively.
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Wang Q, Zhang Q, Zhao X, Luo X, Wong CPY, Wang J, Wan D, Venkatesan T, Pennycook SJ, Loh KP, Eda G, Wee ATS. Photoluminescence Upconversion by Defects in Hexagonal Boron Nitride. NANO LETTERS 2018; 18:6898-6905. [PMID: 30260651 DOI: 10.1021/acs.nanolett.8b02804] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Hexagonal boron nitride (h-BN) was recently reported to display single photon emission from ultraviolet to near-infrared range due to the existence of defects. Single photon emission has potential applications in quantum information processing and optoelectronics. These findings trigger increasing research interests in h-BN defects, such as revealing the nature of the defects. Here, we report another intriguing defect property in h-BN, namely photoluminescence (PL) upconversion (anti-Stokes process). The energy gain by the PL upconversion is about 162 meV. The anomalous PL upconversion is attributed to optical phonon absorption in the one-photon excitation process, based on excitation power, excitation wavelength, and temperature-dependence investigations. Possible constitutions of the defects are discussed from the results of scanning transmission electron microscopy (STEM) studies and theoretical calculations. These findings show that defects in h-BN exhibit strong defect-phonon coupling. The results from STEM and theoretical calculations are beneficial for understanding the constitution of the h-BN defects.
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Affiliation(s)
- Qixing Wang
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
| | - Qi Zhang
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
| | - Xiaoxu Zhao
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , 117543 , Singapore
- Centre for Advanced 2D Materials , National University of Singapore , Block S14, 6 Science Drive 2 , Singapore 117546 , Singapore
- NUS Graduate School for Integrative Sciences and Engineering , National University of Singapore , 13 Centre for Life Sciences, #05-01, 28 Medical Drive , Singapore 117456 , Singapore
| | - Xin Luo
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics , Sun Yat-sen University , Guangzhou 510275 , Guangdong , People's Republic of China
- Department of Applied Physics , the Hong Kong Polytechnic University , Hung Hom, Kowloon, Hong Kong , People's Republic of China
| | - Calvin Pei Yu Wong
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
- NUS Graduate School for Integrative Sciences and Engineering , National University of Singapore , 13 Centre for Life Sciences, #05-01, 28 Medical Drive , Singapore 117456 , Singapore
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR) , 2 Fusionopolis Way, Innovis #08-03 , Singapore 138634 , Singapore
| | - Junyong Wang
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
| | - Dongyang Wan
- NUSNNI-NanoCore , National University of Singapore , 117411 , Singapore
| | - T Venkatesan
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
- NUS Graduate School for Integrative Sciences and Engineering , National University of Singapore , 13 Centre for Life Sciences, #05-01, 28 Medical Drive , Singapore 117456 , Singapore
- NUSNNI-NanoCore , National University of Singapore , 117411 , Singapore
- Department of Materials Science & Engineering , National University of Singapore , 9 Engineering Drive 1 , Singapore 117575 , Singapore
- Department of Electrical and Computer Engineering , National University of Singapore , 9 Engineering Drive 1 , 117575 , Singapore
| | - Stephen J Pennycook
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
- NUS Graduate School for Integrative Sciences and Engineering , National University of Singapore , 13 Centre for Life Sciences, #05-01, 28 Medical Drive , Singapore 117456 , Singapore
- NUSNNI-NanoCore , National University of Singapore , 117411 , Singapore
- Department of Materials Science & Engineering , National University of Singapore , 9 Engineering Drive 1 , Singapore 117575 , Singapore
| | - Kian Ping Loh
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , 117543 , Singapore
- Centre for Advanced 2D Materials , National University of Singapore , Block S14, 6 Science Drive 2 , Singapore 117546 , Singapore
| | - Goki Eda
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , 117543 , Singapore
- Centre for Advanced 2D Materials , National University of Singapore , Block S14, 6 Science Drive 2 , Singapore 117546 , Singapore
| | - Andrew T S Wee
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
- Centre for Advanced 2D Materials , National University of Singapore , Block S14, 6 Science Drive 2 , Singapore 117546 , Singapore
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12
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Mergenthaler K, Anttu N, Vainorius N, Aghaeipour M, Lehmann S, Borgström MT, Samuelson L, Pistol ME. Anti-Stokes photoluminescence probing k-conservation and thermalization of minority carriers in degenerately doped semiconductors. Nat Commun 2017; 8:1634. [PMID: 29158511 PMCID: PMC5696368 DOI: 10.1038/s41467-017-01817-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 10/18/2017] [Indexed: 11/13/2022] Open
Abstract
It has recently been found that anti-Stokes photoluminescence can be observed in degenerately n-doped indium phosphide nanowires, when exciting directly into the electron gas. This anti-Stokes mechanism has not been observed before and allows the study of carrier relaxation and recombination using standard photoluminescence techniques. It is important to know if this anti-Stokes photoluminescence also occurs in bulk semiconductors as well as its relation to carrier recombination and relaxation. Here we show that similar anti-Stokes photoluminescence can indeed be observed in degenerately doped bulk indium phosphide and gallium arsenide and is caused by minority carriers scattering to high momenta by phonons. We find in addition that the radiative electron-hole recombination is highly momentum-conserving and that photogenerated minority carriers recombine before relaxing to the band edge at low temperatures. These observations challenge the use of models assuming thermalization of minority carriers in the analysis of highly doped devices. Anti-Stokes luminescence - the emission of photons with higher energy than those absorbed – in nanomaterials is widely used for optoelectronic applications. Here the authors observe it in degenerately doped bulk InP and GaAs, indicating it as a more general property of direct bandgap semiconductors.
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Affiliation(s)
- K Mergenthaler
- Department of Solid State Physics and NanoLund, Lund University, Box 118, 221 00, Lund, Sweden.
| | - N Anttu
- Department of Solid State Physics and NanoLund, Lund University, Box 118, 221 00, Lund, Sweden
| | - N Vainorius
- Department of Solid State Physics and NanoLund, Lund University, Box 118, 221 00, Lund, Sweden
| | - M Aghaeipour
- Department of Solid State Physics and NanoLund, Lund University, Box 118, 221 00, Lund, Sweden
| | - S Lehmann
- Department of Solid State Physics and NanoLund, Lund University, Box 118, 221 00, Lund, Sweden
| | - M T Borgström
- Department of Solid State Physics and NanoLund, Lund University, Box 118, 221 00, Lund, Sweden
| | - L Samuelson
- Department of Solid State Physics and NanoLund, Lund University, Box 118, 221 00, Lund, Sweden
| | - M-E Pistol
- Department of Solid State Physics and NanoLund, Lund University, Box 118, 221 00, Lund, Sweden.
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13
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Manca M, Glazov MM, Robert C, Cadiz F, Taniguchi T, Watanabe K, Courtade E, Amand T, Renucci P, Marie X, Wang G, Urbaszek B. Enabling valley selective exciton scattering in monolayer WSe 2 through upconversion. Nat Commun 2017; 8:14927. [PMID: 28367962 PMCID: PMC5382264 DOI: 10.1038/ncomms14927] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 02/14/2017] [Indexed: 12/14/2022] Open
Abstract
Excitons, Coulomb bound electron–hole pairs, are composite bosons and their interactions in traditional semiconductors lead to condensation and light amplification. The much stronger Coulomb interaction in transition metal dichalcogenides such as WSe2 monolayers combined with the presence of the valley degree of freedom is expected to provide new opportunities for controlling excitonic effects. But so far the bosonic character of exciton scattering processes remains largely unexplored in these two-dimensional materials. Here we show that scattering between B-excitons and A-excitons preferably happens within the same valley in momentum space. This leads to power dependent, negative polarization of the hot B-exciton emission. We use a selective upconversion technique for efficient generation of B-excitons in the presence of resonantly excited A-excitons at lower energy; we also observe the excited A-excitons state 2s. Detuning of the continuous wave, low-power laser excitation outside the A-exciton resonance (with a full width at half maximum of 4 meV) results in vanishing upconversion signal. Monolayer transition metal dichalcogenides host excitons, bound electron-hole pairs that play a pivotal role in optoelectronic applications relying on strong light-matter interaction. Here, the authors unveil the spectroscopic signature of boson scattering of two-dimensional excitons in monolayer WSe2.
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Affiliation(s)
- M Manca
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, Toulouse 31077, France
| | - M M Glazov
- Ioffe Institute, St Petersburg 194021, Russia
| | - C Robert
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, Toulouse 31077, France
| | - F Cadiz
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, Toulouse 31077, France
| | - T Taniguchi
- National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - K Watanabe
- National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - E Courtade
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, Toulouse 31077, France
| | - T Amand
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, Toulouse 31077, France
| | - P Renucci
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, Toulouse 31077, France
| | - X Marie
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, Toulouse 31077, France
| | - G Wang
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, Toulouse 31077, France
| | - B Urbaszek
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, Toulouse 31077, France
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14
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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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15
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Mergenthaler K, Lehmann S, Wallentin J, Zhang W, Borgström MT, Yartsev A, Pistol ME. Photon upconversion in degenerately sulfur doped InP nanowires. NANOSCALE 2015; 7:20503-20509. [PMID: 26585229 DOI: 10.1039/c5nr05472a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Radiative recombination in degenerately n-doped InP nanowires is studied for excitation above and below the Fermi energy of the electron gas, using photoluminescence. Laser-induced electron heating is observed, which allows absorption below the Fermi energy. We observe photon upconversion where photo-excited holes recombine with high |k| electrons. This can be attributed to hole scattering to high |k|-values, and the temperature dependence of this process is measured. We show that hole relaxation via phonon scattering can be observed in continuous wave excitation luminescence measurements.
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Affiliation(s)
- K Mergenthaler
- Department of Solid State Physics/The Nanaometer Structure Consortium, Lund University, Box 118, 221 00 Lund, Sweden.
| | - S Lehmann
- Department of Solid State Physics/The Nanaometer Structure Consortium, Lund University, Box 118, 221 00 Lund, Sweden.
| | - J Wallentin
- Institute for X-ray Physics, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - W Zhang
- Division of Chemical Physics, Lund University, Box 124, 221 00 Lund, Sweden
| | - M T Borgström
- Department of Solid State Physics/The Nanaometer Structure Consortium, Lund University, Box 118, 221 00 Lund, Sweden.
| | - A Yartsev
- Division of Chemical Physics, Lund University, Box 124, 221 00 Lund, Sweden
| | - M-E Pistol
- Department of Solid State Physics/The Nanaometer Structure Consortium, Lund University, Box 118, 221 00 Lund, Sweden.
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16
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Nishihara T, Tahara H, Okano M, Ono M, Kanemitsu Y. Fast Dissociation and Reduced Auger Recombination of Multiple Excitons in Closely Packed PbS Nanocrystal Thin Films. J Phys Chem Lett 2015; 6:1327-32. [PMID: 26263131 DOI: 10.1021/acs.jpclett.5b00293] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Exciton decay dynamics in chemically treated PbS quantum-dot (QD) films have been studied using femtosecond transient-absorption (TA) spectroscopy. In photoconductive QD films, a decay component with a lifetime of a few nanoseconds appeared in the TA signals because of exciton dissociation under weak excitation. Increasing excitation fluence resulted in additional fast-decay components corresponding to the lifetimes of multiple excitons, which decreased with increasing photoconductivity of the closely packed QD films. Auger recombination in photoexcited QDs was suppressed in highly photoconductive films. Our findings clearly show that the carrier transfer between the QDs dominates the lifetimes of single and multiple excitons.
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Affiliation(s)
- Taishi Nishihara
- †Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Hirokazu Tahara
- †Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Makoto Okano
- †Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Masashi Ono
- ‡Frontier Core-Technology Laboratories, Fujifilm Corporation, Ashigarakami-gun, Kanagawa 258-8577, Japan
| | - Yoshihiko Kanemitsu
- †Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
- §Japan Science and Technology Agency, CREST, Kyoto University, Uji, Kyoto 611-0011, Japan
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17
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Wang L, Long R, Prezhdo OV. Time-Domain Ab Initio Modeling of Photoinduced Dynamics at Nanoscale Interfaces. Annu Rev Phys Chem 2015; 66:549-79. [DOI: 10.1146/annurev-physchem-040214-121359] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Linjun Wang
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482;
- Department of Chemistry, University of Rochester, Rochester, New York 14627
| | - Run Long
- School of Physics and Complex & Adaptive Systems Laboratory, University College Dublin, Belfield, Dublin 4, Ireland
| | - Oleg V. Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482;
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18
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Suh J, Park TE, Lin DY, Fu D, Park J, Jung HJ, Chen Y, Ko C, Jang C, Sun Y, Sinclair R, Chang J, Tongay S, Wu J. Doping against the native propensity of MoS2: degenerate hole doping by cation substitution. NANO LETTERS 2014; 14:6976-82. [PMID: 25420217 DOI: 10.1021/nl503251h] [Citation(s) in RCA: 259] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Layered transition metal dichalcogenides (TMDs) draw much attention as the key semiconducting material for two-dimensional electrical, optoelectronic, and spintronic devices. For most of these applications, both n- and p-type materials are needed to form junctions and support bipolar carrier conduction. However, typically only one type of doping is stable for a particular TMD. For example, molybdenum disulfide (MoS2) is natively an n-type presumably due to omnipresent electron-donating sulfur vacancies, and stable/controllable p-type doping has not been achieved. The lack of p-type doping hampers the development of charge-splitting p-n junctions of MoS2, as well as limits carrier conduction to spin-degenerate conduction bands instead of the more interesting, spin-polarized valence bands. Traditionally, extrinsic p-type doping in TMDs has been approached with surface adsorption or intercalation of electron-accepting molecules. However, practically stable doping requires substitution of host atoms with dopants where the doping is secured by covalent bonding. In this work, we demonstrate stable p-type conduction in MoS2 by substitutional niobium (Nb) doping, leading to a degenerate hole density of ∼ 3 × 10(19) cm(-3). Structural and X-ray techniques reveal that the Nb atoms are indeed substitutionally incorporated into MoS2 by replacing the Mo cations in the host lattice. van der Waals p-n homojunctions based on vertically stacked MoS2 layers are fabricated, which enable gate-tunable current rectification. A wide range of microelectronic, optoelectronic, and spintronic devices can be envisioned from the demonstrated substitutional bipolar doping of MoS2. From the miscibility of dopants with the host, it is also expected that the synthesis technique demonstrated here can be generally extended to other TMDs for doping against their native unipolar propensity.
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Affiliation(s)
- Joonki Suh
- Department of Materials Science and Engineering, University of California , Berkeley, California 94720, United States
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19
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Wang L, Trivedi D, Prezhdo OV. Global Flux Surface Hopping Approach for Mixed Quantum-Classical Dynamics. J Chem Theory Comput 2014; 10:3598-605. [DOI: 10.1021/ct5003835] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Linjun Wang
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Dhara Trivedi
- Department of Physics & Astronomy, University of Rochester, Rochester, New York 14627, United States
| | - Oleg V. Prezhdo
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
- Department of Physics & Astronomy, University of Rochester, Rochester, New York 14627, United States
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20
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Tex DM, Kamiya I, Kanemitsu Y. Control of hot-carrier relaxation for realizing ideal quantum-dot intermediate-band solar cells. Sci Rep 2014; 4:4125. [PMID: 24535195 PMCID: PMC3927209 DOI: 10.1038/srep04125] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 02/03/2014] [Indexed: 11/16/2022] Open
Abstract
For intermediate-band solar cells, the broad absorption spectrum of quantum dots (QDs) offers a favorable conversion efficiency, and photocurrent generation via efficient two-step two-photon-absorption (TS-TPA) in QDs is essential for realizing high-performance solar cells. In the last decade, many works were dedicated to improve the TS-TPA efficiency by modifying the QD itself, however, the obtained results are far from the requirements for practical applications. To reveal the mechanisms behind the low TS-TPA efficiency in QDs, we report here on two- and three-beam photocurrent measurements of InAs quantum structures embedded in AlGaAs. Comparison of two- and three-beam photocurrent spectra obtained by subbandgap excitation reveals that the QD TS-TPA efficiency is improved significantly by suppressing the relaxation of hot TS-TPA carriers to unoccupied shallow InAs quantum structure states.
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Affiliation(s)
- David M Tex
- 1] Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011 Japan [2] Japan Science and Technology Agency, CREST, Uji, Kyoto, 611-0011 Japan
| | - Itaru Kamiya
- Toyota Technological Institute, Nagoya, Aichi, 468-8511 Japan
| | - Yoshihiko Kanemitsu
- 1] Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011 Japan [2] Japan Science and Technology Agency, CREST, Uji, Kyoto, 611-0011 Japan
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21
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Xu Q, Piermarocchi C, Pershin YV, Salamo GJ, Xiao M, Wang X, Shih CK. Giant up-conversion efficiency of InGaAs quantum dots in a planar microcavity. Sci Rep 2014; 4:3953. [PMID: 24492329 PMCID: PMC3912475 DOI: 10.1038/srep03953] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 01/16/2014] [Indexed: 11/16/2022] Open
Abstract
Self-assembled InGaAs quantum dots (QDs) were fabricated inside a planar microcavity with two vertical cavity modes. This allowed us to excite the QDs coupled to one of the vertical cavity modes through two propagating cavity modes to study their down- and up-converted photoluminescence (PL). The up-converted PL increased continuously with the increasing temperature, reaching an intensity level comparable to that of the down-converted PL at ~120 K. This giant efficiency in the up-converted PL of InGaAs QDs was enhanced by about 2 orders of magnitude with respect to a similar structure without cavity. We tentatively explain the enhanced up-converted signal as a direct consequence of the modified spontaneous emission properties of the QDs in the microcavity, combined with the phonon absorption and emission effects.
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Affiliation(s)
- Qinfeng Xu
- 1] National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China [2] Department of Physics and Optoelectronic Engineering, Ludong University, Yantai 264025, China
| | - Carlo Piermarocchi
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA
| | - Yuriy V Pershin
- Department of Physics and Astronomy and USC Nanocenter, University of South Carolina, Columbia, SC 29208, USA
| | - G J Salamo
- Department of Physics, University of Arkansas, Fayetteville, AR 72701, USA
| | - Min Xiao
- 1] National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China [2] Department of Physics, University of Arkansas, Fayetteville, AR 72701, USA
| | - Xiaoyong Wang
- 1] National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China [2] Department of Physics, the University of Texas at Austin, Austin, TX 78712, USA
| | - Chih-Kang Shih
- Department of Physics, the University of Texas at Austin, Austin, TX 78712, USA
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22
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Deutsch Z, Neeman L, Oron D. Luminescence upconversion in colloidal double quantum dots. NATURE NANOTECHNOLOGY 2013; 8:649-53. [PMID: 23912060 DOI: 10.1038/nnano.2013.146] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 06/25/2013] [Indexed: 05/25/2023]
Abstract
Luminescence upconversion nanocrystals capable of converting two low-energy photons into a single photon at a higher energy are sought-after for a variety of applications, including bioimaging and photovoltaic light harvesting. Currently available systems, based on rare-earth-doped dielectrics, are limited in both tunability and absorption cross-section. Here we present colloidal double quantum dots as an alternative nanocrystalline upconversion system, combining the stability of an inorganic crystalline structure with the spectral tunability afforded by quantum confinement. By tailoring its composition and morphology, we form a semiconducting nanostructure in which excited electrons are delocalized over the entire structure, but a double potential well is formed for holes. Upconversion occurs by excitation of an electron in the lower energy transition, followed by intraband absorption of the hole, allowing it to cross the barrier to a higher energy state. An overall conversion efficiency of 0.1% per double excitation event is achieved.
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Affiliation(s)
- Zvicka Deutsch
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
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23
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Tenne R, Teitelboim A, Rukenstein P, Dyshel M, Mokari T, Oron D. Studying quantum dot blinking through the addition of an engineered inorganic hole trap. ACS NANO 2013; 7:5084-90. [PMID: 23668262 DOI: 10.1021/nn4017845] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
An all-inorganic compound colloidal quantum dot incorporating a highly emissive CdSe core, which is linked by a CdS tunneling barrier to an engineered charge carrier trap composed of PbS, is designed, and its optical properties are studied in detail at the single-particle level. Study of this structure enables a deeper understanding of the link between photoinduced charging and surface trapping of charge carriers and the phenomenon of quantum dot blinking. In the presence of the hole trap, a "gray" emissive state appears, associated with charging of the core. Rapid switching is observed between the "on" and the "gray" state, although the switching dynamics in and out of the dark "off" state remain unaffected. This result completes the links in the causality chain connecting charge carrier trapping, charging of QDs, and the appearance of a "gray" emission state.
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Affiliation(s)
- Ron Tenne
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
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24
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Wheeler DA, Zhang JZ. Exciton dynamics in semiconductor nanocrystals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:2878-2896. [PMID: 23625792 DOI: 10.1002/adma.201300362] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Indexed: 06/02/2023]
Abstract
This review article provides an overview of recent advances in the study and understanding of dynamics of excitons in semiconductor nanocrystals (NCs) or quantum dots (QDs). Emphasis is placed on the relationship between exciton dynamics and optical properties, both linear and nonlinear. We also focus on the unique aspects of exciton dynamics in semiconductor NCs as compared to those in bulk crystals. Various experimental techniques for probing exciton dynamics, particularly time-resolved laser methods, are reviewed. Relevant models and computational studies are also briefly presented. By comparing different materials systems, a unifying picture is proposed to account for the major dynamic features of excitons in semiconductor QDs. While the specific dynamic processes involved are material-dependent, key processes can be identified for all the materials that include electronic dephasing, intraband relaxation, trapping, and interband recombination of free and trapped charge carriers (electron and hole). Exciton dynamics play a critical role in the fundamental properties and functionalities of nanomaterials of interest for a variety of applications including optical detectors, solar energy conversion, lasers, and sensors. A better understanding of exciton dynamics in nanomaterials is thus important both fundamentally and technologically.
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Affiliation(s)
- Damon A Wheeler
- Department of Chemistry & Biochemistry, University of California, Santa Cruz, CA 95064 USA, Fax: (831) 459-3776
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25
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Abazović ND, Comor MI, Dramićanin MD, Jovanović DJ, Ahrenkiel SP, Nedeljković JM. Photoluminescence of Anatase and Rutile TiO2Particles†. J Phys Chem B 2006; 110:25366-70. [PMID: 17165983 DOI: 10.1021/jp064454f] [Citation(s) in RCA: 342] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nonaqueous reactions between titanium(IV) chloride and alcohols (benzyl alcohol or n-butanol) were used for the synthesis of anatase TiO2 particles, while rutile TiO2 particles were synthesized in aqueous media by acidic hydrolysis of titanium(IV) chloride. The X-ray diffraction measurements proved the exclusive presence of either the anatase or the rutile phase in prepared samples. The photoluminescence of both kinds of particles (anatase and rutile) with several well-resolved peaks extending in the visible spectral region was observed, and the quantum yield at room temperature was found to be 0.25%. Photon energy up-conversion from colloidal anatase and rutile TiO2 particles was observed at low excitation intensities. The energy of up-converted photoluminescence spans the range of emission of normal photoluminescence. The explanation of photon energy up-conversion involves mid-gap energy levels originating from oxygen vacancies.
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Affiliation(s)
- Nadica D Abazović
- Vincca Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade, Serbia
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26
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Dantas NO, Qu F, Silva RS, Morais PC. Anti-Stokes Photoluminescence in Nanocrystal Quantum Dots. J Phys Chem B 2002. [DOI: 10.1021/jp0208743] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Noelio Oliveira Dantas
- Universidade Federal de Uberlândia, Faculdade de Física, Laboratório de Novos Materiais Isolantes e Semicondutores, C.P. 593, CEP 38400-902, Uberlândia (MG), Brazil
| | - Fanyao Qu
- Universidade Federal de Uberlândia, Faculdade de Física, Laboratório de Novos Materiais Isolantes e Semicondutores, C.P. 593, CEP 38400-902, Uberlândia (MG), Brazil
| | - R. S. Silva
- Universidade Federal de Uberlândia, Faculdade de Física, Laboratório de Novos Materiais Isolantes e Semicondutores, C.P. 593, CEP 38400-902, Uberlândia (MG), Brazil
| | - Paulo César Morais
- Universidade de Brasília, Instituto de Física, Núcleo de Física Aplicada, C.P. 04455, CEP 70919-970, Brasília (DF), Brazil
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27
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Kammerer C, Cassabois G, Voisin C, Delalande C, Roussignol P, Gérard JM. Photoluminescence up-conversion in single self-assembled InAs/GaAs quantum dots. PHYSICAL REVIEW LETTERS 2001; 87:207401. [PMID: 11690509 DOI: 10.1103/physrevlett.87.207401] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2001] [Indexed: 05/23/2023]
Abstract
Microphotoluminescence measurements under cw excitation reveal the existence of a strong photoluminescence up-conversion from single InAs/GaAs self-assembled quantum dots and also from the InAs wetting layer. Excitation spectroscopy of the up-converted photoluminescence signal shows identical features from the wetting layer and the single quantum dots, i.e., a band tail coming from the deep states localized at the rough interfaces of the wetting layer quantum well. This observation of photoluminescence up-conversion demonstrates the influence on the quantum dot properties of the environment, and highlights the limitations of the artificial atom model for a semiconductor quantum dot.
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Affiliation(s)
- C Kammerer
- Laboratoire de Physique de la Matière Condensée de l'Ecole Normale Supérieure, 24 rue Lhomond, 75231 Paris Cedex 05, France
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29
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Driessen FA, Cheong HM, Mascarenhas A, Deb SK, Hageman PR, Bauhuis GJ, Giling LJ. Interface-induced conversion of infrared to visible light at semiconductor interfaces. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:R5263-R5266. [PMID: 9986584 DOI: 10.1103/physrevb.54.r5263] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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30
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Hellmann R, Euteneuer A, Hense SG, Feldmann J, Thomas P, Göbel EO, Yakovlev DR, Waag A, Landwehr G. Low-temperature anti-Stokes luminescence mediated by disorder in semiconductor quantum-well structures. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:18053-18056. [PMID: 9978854 DOI: 10.1103/physrevb.51.18053] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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