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Wong EL, Folpini G, Zhou Y, Albaqami MD, Petrozza A. Electron Spectroscopy and Microscopy: A Window into the Surface Electronic Properties of Polycrystalline Metal Halide Perovskites. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2310240. [PMID: 38708696 DOI: 10.1002/adma.202310240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 03/04/2024] [Indexed: 05/07/2024]
Abstract
In the past years, an increasing number of experimental techniques have emerged to address the need to unveil the chemical, structural, and electronic properties of perovskite thin films with high vertical and lateral spatial resolutions. One of these is angle-resolved photoemission electron spectroscopy which can provide direct access to the electronic band structure of perovskites, with the aim of overcoming elusive and controversial information due to the complex data interpretation of purely optical spectroscopic techniques. This perspective looks at the information that can be gleaned from the direct measurement of the electronic band structure of single crystal perovskites and the challenges that remain to be overcame to extend this technique to heterogeneous polycrystalline metal halide perovskites.
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Affiliation(s)
- E Laine Wong
- Center for Nano Science and Technology, Istituto Italiano di Tecnologia, Via Raffaele Rubattino, 81, Milano, 20134, Italy
| | - Giulia Folpini
- Center for Nano Science and Technology, Istituto Italiano di Tecnologia, Via Raffaele Rubattino, 81, Milano, 20134, Italy
| | - Yang Zhou
- Center for Nano Science and Technology, Istituto Italiano di Tecnologia, Via Raffaele Rubattino, 81, Milano, 20134, Italy
| | - Minirah Dukhi Albaqami
- Chemistry Department, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Annamaria Petrozza
- Center for Nano Science and Technology, Istituto Italiano di Tecnologia, Via Raffaele Rubattino, 81, Milano, 20134, Italy
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2
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Lyu X, Li Y, Li X, Liu X, Xiao J, Xu W, Jiang P, Yang H, Wu C, Hu X, Peng LY, Gong Q, Yang S, Gao Y. Layer-dependent ultrafast carrier dynamics of PdSe 2 investigated by photoemission electron microscopy. NANOSCALE 2024. [PMID: 38656387 DOI: 10.1039/d4nr00281d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
For atomically thin two-dimensional materials, variations in layer thickness can result in significant changes in the electronic energy band structure and physicochemical properties, thereby influencing the carrier dynamics and device performance. In this work, we employ time- and energy-resolved photoemission electron microscopy to reveal the ultrafast carrier dynamics of PdSe2 with different layer thicknesses. We find that for few-layer PdSe2 with a semiconductor phase, an ultrafast hot carrier cooling on a timescale of approximately 0.3 ps and an ultrafast defect trapping on a timescale of approximately 1.3 ps are unveiled, followed by a slower decay of approximately tens of picoseconds. However, for bulk PdSe2 with a semimetal phase, only an ultrafast hot carrier cooling and a slower decay of approximately tens of picoseconds are observed, while the contribution of defect trapping is suppressed with the increase of layer number. Theoretical calculations of the electronic energy band structure further confirm the transition from a semiconductor to a semimetal. Our work demonstrates that TR- and ER-PEEM with ultrahigh spatiotemporal resolution and wide-field imaging capability has great advantages in revealing the intricate details of ultrafast carrier dynamics of nanomaterials.
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Affiliation(s)
- Xiaying Lyu
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China.
| | - Yaolong Li
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China.
| | - Xiaofang Li
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China.
| | - Xiulan Liu
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China.
| | - Jingying Xiao
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China.
| | - Weiting Xu
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China.
| | - Pengzuo Jiang
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China.
| | - Hong Yang
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China.
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Chengyin Wu
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China.
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Xiaoyong Hu
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China.
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Liang-You Peng
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China.
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Qihuang Gong
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China.
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Shengxue Yang
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China.
| | - Yunan Gao
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China.
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
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3
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Xu C, Barden N, Alexeev EM, Wang X, Long R, Cadore AR, Paradisanos I, Ott AK, Soavi G, Tongay S, Cerullo G, Ferrari AC, Prezhdo OV, Loh ZH. Ultrafast Charge Transfer and Recombination Dynamics in Monolayer-Multilayer WSe 2 Junctions Revealed by Time-Resolved Photoemission Electron Microscopy. ACS NANO 2024; 18:1931-1947. [PMID: 38197410 DOI: 10.1021/acsnano.3c06473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
The ultrafast carrier dynamics of junctions between two chemically identical, but electronically distinct, transition metal dichalcogenides (TMDs) remains largely unknown. Here, we employ time-resolved photoemission electron microscopy (TR-PEEM) to probe the ultrafast carrier dynamics of a monolayer-to-multilayer (1L-ML) WSe2 junction. The TR-PEEM signals recorded for the individual components of the junction reveal the sub-ps carrier cooling dynamics of 1L- and 7L-WSe2, as well as few-ps exciton-exciton annihilation occurring on 1L-WSe2. We observe ultrafast interfacial hole (h) transfer from 1L- to 7L-WSe2 on an ∼0.2 ps time scale. The resultant excess h density in 7L-WSe2 decays by carrier recombination across the junction interface on an ∼100 ps time scale. Reminiscent of the behavior at a depletion region, the TR-PEEM image reveals the h density accumulation on the 7L-WSe2 interface, with a decay length ∼0.60 ± 0.17 μm. These charge transfer and recombination dynamics are in agreement with ab initio quantum dynamics. The computed orbital densities reveal that charge transfer occurs from the basal plane, which extends over both 1L and ML regions, to the upper plane localized on the ML region. This mode of charge transfer is distinctive to chemically homogeneous junctions of layered materials and constitutes an additional carrier deactivation pathway that should be considered in studies of 1L-TMDs found alongside their ML, a common occurrence in exfoliated samples.
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Affiliation(s)
- Ce Xu
- School of Chemistry, Chemical Engineering and Biotechnology, and School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Natalie Barden
- School of Chemistry, Chemical Engineering and Biotechnology, and School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Evgeny M Alexeev
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, U.K
| | - Xiaoli Wang
- College of Chemistry, Key Laboratory of Theoretical and Computational Photochemistry, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical and Computational Photochemistry, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Alisson R Cadore
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, U.K
| | | | - Anna K Ott
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, U.K
| | - Giancarlo Soavi
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, U.K
- Institute of Solid State Physics, Friedrich Schiller University Jena, Max-Wien-Platz 1, 07743 Jena, Germany
| | - Sefaattin Tongay
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Giulio Cerullo
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
- IFN-CNR, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Andrea C Ferrari
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, U.K
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Zhi-Heng Loh
- School of Chemistry, Chemical Engineering and Biotechnology, and School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
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4
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Winchester AJ, Anderson TJ, Hite JK, Elmquist RE, Pookpanratana S. Methodology and implementation of a tunable deep-ultraviolet laser source for photoemission electron microscopy. Ultramicroscopy 2023; 253:113819. [PMID: 37549583 DOI: 10.1016/j.ultramic.2023.113819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 06/21/2023] [Accepted: 07/25/2023] [Indexed: 08/09/2023]
Abstract
Photoemission electron microscopy (PEEM) is a unique and powerful tool for studying the electronic properties of materials and surfaces. However, it requires intense and well-controlled light sources with photon energies ranging from the UV to soft X-rays for achieving high spatial resolution and image contrast. Traditionally, many PEEMs were installed at synchrotron light sources to access intense and tunable soft X-rays. More recently, the maturation of solid-state lasers has opened a new avenue for laboratory-based PEEMs using laser-based UV light at lower photon energies. Here, we report on the characteristics of a laser-based UV light source that was recently integrated with a PEEM instrument. The system consists of a high repetition rate, tunable wavelength laser coupled to a harmonics generation module, which generates deep-UV radiation from 192 nm to 210 nm. We comment on the spectral characteristics and overall laser system stability, as well as on the effects of space charge within the PEEM microscope at high UV laser fluxes. Further, we show an example of imaging on gallium nitride, where the higher UV photon energy and flux of the laser provides considerably improved image quality, compared to a conventional light source. These results demonstrate the capabilities of laser-based UV light sources for advancing laboratory-based PEEMs.
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Affiliation(s)
- Andrew J Winchester
- Nanoscale Device and Characterization Division, National Institute of Standards and Technology, Gaithersburg, MD, United States
| | - Travis J Anderson
- Electronics Science and Technology Division, U.S. Naval Research Laboratory, Washington, DC, United States
| | - Jennifer K Hite
- Electronics Science and Technology Division, U.S. Naval Research Laboratory, Washington, DC, United States
| | - Randolph E Elmquist
- Quantum Measurement Division, National Institute of Standards and Technology, Gaithersburg, MD, United States
| | - Sujitra Pookpanratana
- Nanoscale Device and Characterization Division, National Institute of Standards and Technology, Gaithersburg, MD, United States.
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5
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Lyu X, Li Y, Jiang P, Zhang J, Liu X, Li X, Yang H, Lu G, Hu X, Peng L, Gong Q, Gao Y. Reveal Ultrafast Electron Relaxation across Sub-bands of Tellurium by Time- and Energy-Resolved Photoemission Microscopy. NANO LETTERS 2023; 23:9547-9554. [PMID: 37816225 DOI: 10.1021/acs.nanolett.3c03102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/12/2023]
Abstract
Exploring ultrafast carrier dynamics is crucial for the materials' fundamental properties and device design. In this work, we employ time- and energy-resolved photoemission electron microscopy with tunable pump wavelengths from visible to near-infrared to reveal the ultrafast carrier dynamics of the elemental semiconductor tellurium. We find that two discrete sub-bands around the Γ point of the conduction band are involved in excited-state electron ultrafast relaxation and reveal that hot electrons first go through ultrafast intra sub-band cooling on a time scale of about 0.3 ps and then transfer from the higher sub-band to the lower one on a time scale of approximately 1 ps. Additionally, theoretical calculations reveal that the lower one has flat-band characteristics, possessing a large density of states and a long electron lifetime. Our work demonstrates that TR- and ER-PEEM with broad tunable pump wavelengths are powerful techniques in revealing the details of ultrafast carrier dynamics in time and energy domains.
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Affiliation(s)
- Xiaying Lyu
- State Key Laboratory for Mesoscopic Physics & Department of Physics and Frontiers Science Center for Nano-optoelectronics, Peking University, Beijing 100871, China
| | - Yaolong Li
- State Key Laboratory for Mesoscopic Physics & Department of Physics and Frontiers Science Center for Nano-optoelectronics, Peking University, Beijing 100871, China
| | - Pengzuo Jiang
- State Key Laboratory for Mesoscopic Physics & Department of Physics and Frontiers Science Center for Nano-optoelectronics, Peking University, Beijing 100871, China
| | - Jianing Zhang
- State Key Laboratory for Mesoscopic Physics & Department of Physics and Frontiers Science Center for Nano-optoelectronics, Peking University, Beijing 100871, China
| | - Xiulan Liu
- State Key Laboratory for Mesoscopic Physics & Department of Physics and Frontiers Science Center for Nano-optoelectronics, Peking University, Beijing 100871, China
| | - Xiaofang Li
- State Key Laboratory for Mesoscopic Physics & Department of Physics and Frontiers Science Center for Nano-optoelectronics, Peking University, Beijing 100871, China
| | - Hong Yang
- State Key Laboratory for Mesoscopic Physics & Department of Physics and Frontiers Science Center for Nano-optoelectronics, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Guowei Lu
- State Key Laboratory for Mesoscopic Physics & Department of Physics and Frontiers Science Center for Nano-optoelectronics, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Xiaoyong Hu
- State Key Laboratory for Mesoscopic Physics & Department of Physics and Frontiers Science Center for Nano-optoelectronics, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Liangyou Peng
- State Key Laboratory for Mesoscopic Physics & Department of Physics and Frontiers Science Center for Nano-optoelectronics, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Qihuang Gong
- State Key Laboratory for Mesoscopic Physics & Department of Physics and Frontiers Science Center for Nano-optoelectronics, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Yunan Gao
- State Key Laboratory for Mesoscopic Physics & Department of Physics and Frontiers Science Center for Nano-optoelectronics, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
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Qin Y, Wang R, Wu X, Wang Y, Li X, Gao Y, Peng L, Gong Q, Liu Y. Ultrafast Electronic Dynamics in Anisotropic Indirect Interlayer Excitonic States of Monolayer WSe 2/ReS 2 Heterojunctions. NANO LETTERS 2023; 23:8643-8649. [PMID: 37672749 DOI: 10.1021/acs.nanolett.3c02488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/08/2023]
Abstract
Understanding ultrafast electronic dynamics of the interlayer excitonic states in atomically thin transition metal dichalcogenides is of importance in engineering valleytronics and developing excitonic integrated circuits. In this work, we experimentally explored the ultrafast dynamics of indirect interlayer excitonic states in monolayer type II WSe2/ReS2 heterojunctions using time-resolved photoemission electron microscopy, which reveals its anisotropic behavior. The ultrafast cooling and decay of excited-state electrons exhibit significant linear dichroism. The ab initio theoretical calculations provide unambiguous evidence that this linear dichroism result is primarily associated with the anisotropic nonradiative recombination of indirect interlayer excitonic states. Measuring time-resolved photoemission energy spectra, we have further revealed the ultrafast evolution of excited-state electrons in anisotropic indirect interlayer excitonic states. The findings have important implications for controlling the interlayer moiré excitonic effects and designing anisotropic optoelectronic devices.
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Affiliation(s)
- Yulu Qin
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Rui Wang
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Xiaoyuan Wu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Yunkun Wang
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Xiaofang Li
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Yunan Gao
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Liangyou Peng
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Qihuang Gong
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Yunquan Liu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
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Xu C, Zhou G, Alexeev EM, Cadore AR, Paradisanos I, Ott AK, Soavi G, Tongay S, Cerullo G, Ferrari AC, Prezhdo OV, Loh ZH. Ultrafast Electronic Relaxation Dynamics of Atomically Thin MoS 2 Is Accelerated by Wrinkling. ACS NANO 2023; 17:16682-16694. [PMID: 37581747 DOI: 10.1021/acsnano.3c02917] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/16/2023]
Abstract
Strain engineering is an attractive approach for tuning the local optoelectronic properties of transition metal dichalcogenides (TMDs). While strain has been shown to affect the nanosecond carrier recombination dynamics of TMDs, its influence on the sub-picosecond electronic relaxation dynamics is still unexplored. Here, we employ a combination of time-resolved photoemission electron microscopy (TR-PEEM) and nonadiabatic ab initio molecular dynamics (NAMD) to investigate the ultrafast dynamics of wrinkled multilayer (ML) MoS2 comprising 17 layers. Following 2.41 eV photoexcitation, electronic relaxation at the Γ valley occurs with a time constant of 97 ± 2 fs for wrinkled ML-MoS2 and 120 ± 2 fs for flat ML-MoS2. NAMD shows that wrinkling permits larger amplitude motions of MoS2 layers, relaxes electron-phonon coupling selection rules, perturbs chemical bonding, and increases the electronic density of states. As a result, the nonadiabatic coupling grows and electronic relaxation becomes faster compared to flat ML-MoS2. Our study suggests that the sub-picosecond electronic relaxation dynamics of TMDs is amenable to strain engineering and that applications which require long-lived hot carriers, such as hot-electron-driven light harvesting and photocatalysis, should employ wrinkle-free TMDs.
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Affiliation(s)
- Ce Xu
- School of Chemistry, Chemical Engineering and Biotechnology, and School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Guoqing Zhou
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
| | - Evgeny M Alexeev
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Alisson R Cadore
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Ioannis Paradisanos
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Anna K Ott
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Giancarlo Soavi
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Sefaattin Tongay
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Giulio Cerullo
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
- IFN-CNR, Piazza Leonardo da Vinci 32, I-20133, Milano, Italy
| | - Andrea C Ferrari
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Oleg V Prezhdo
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Zhi-Heng Loh
- School of Chemistry, Chemical Engineering and Biotechnology, and School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
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8
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Ni F, Li H, Liu H, Zheng Y, Chen X. High-speed optical pulse shaping based on programmable lithium niobate spatial light modulators. OPTICS LETTERS 2023; 48:884-887. [PMID: 36790966 DOI: 10.1364/ol.477967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 01/06/2023] [Indexed: 06/18/2023]
Abstract
Pulse shaping plays a key role in various applications of ultrafast lasers, such as optical communications, laser micromachining, microscopy, and quantum coherent control. Conventional pulse shaping devices based on liquid crystal spatial light modulators (LCSLMs) or digital micromirror devices (DMDs) only have the shaping speed of several hertz to kilohertz, which is not suitable for applications requiring a high-speed response. Here, we demonstrate a high-speed programmable lithium niobate spatial light modulator (LNSLM) with 128 individual modulation channels and a modulation speed that can reach 1 MHz. Then we establish a high-speed LNSLM-based Fourier-transform (FT) pulse shaper to realize high-speed pulse shaping, and the update rate can reach 350 kHz, only limited by the electric circuit. The proposed high-speed pulse shaper scheme opens new avenues for future applications of ultrafast science, such as microscopic imaging, interaction between light and matter, and spectroscopy.
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Kosar S, Winchester AJ, Doherty TAS, Macpherson S, Petoukhoff CE, Frohna K, Anaya M, Chan NS, Madéo J, Man MKL, Stranks SD, Dani KM. Unraveling the varied nature and roles of defects in hybrid halide perovskites with time-resolved photoemission electron microscopy. ENERGY & ENVIRONMENTAL SCIENCE 2021; 14:6320-6328. [PMID: 35003331 PMCID: PMC8658252 DOI: 10.1039/d1ee02055b] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 09/01/2021] [Indexed: 06/14/2023]
Abstract
With rapidly growing photoconversion efficiencies, hybrid perovskite solar cells have emerged as promising contenders for next generation, low-cost photovoltaic technologies. Yet, the presence of nanoscale defect clusters, that form during the fabrication process, remains critical to overall device operation, including efficiency and long-term stability. To successfully deploy hybrid perovskites, we must understand the nature of the different types of defects, assess their potentially varied roles in device performance, and understand how they respond to passivation strategies. Here, by correlating photoemission and synchrotron-based scanning probe X-ray microscopies, we unveil three different types of defect clusters in state-of-the-art triple cation mixed halide perovskite thin films. Incorporating ultrafast time-resolution into our photoemission measurements, we show that defect clusters originating at grain boundaries are the most detrimental for photocarrier trapping, while lead iodide defect clusters are relatively benign. Hexagonal polytype defect clusters are only mildly detrimental individually, but can have a significant impact overall if abundant in occurrence. We also show that passivating defects with oxygen in the presence of light, a previously used approach to improve efficiency, has a varied impact on the different types of defects. Even with just mild oxygen treatment, the grain boundary defects are completely healed, while the lead iodide defects begin to show signs of chemical alteration. Our findings highlight the need for multi-pronged strategies tailored to selectively address the detrimental impact of the different defect types in hybrid perovskite solar cells.
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Affiliation(s)
- Sofiia Kosar
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University Onna Okinawa 904 0495 Japan
| | - Andrew J Winchester
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University Onna Okinawa 904 0495 Japan
| | - Tiarnan A S Doherty
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue Cambridge CB3 0HE UK
| | - Stuart Macpherson
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue Cambridge CB3 0HE UK
| | - Christopher E Petoukhoff
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University Onna Okinawa 904 0495 Japan
| | - Kyle Frohna
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue Cambridge CB3 0HE UK
| | - Miguel Anaya
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue Cambridge CB3 0HE UK
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive Cambridge CB3 0AS UK
| | - Nicholas S Chan
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University Onna Okinawa 904 0495 Japan
| | - Julien Madéo
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University Onna Okinawa 904 0495 Japan
| | - Michael K L Man
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University Onna Okinawa 904 0495 Japan
| | - Samuel D Stranks
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue Cambridge CB3 0HE UK
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive Cambridge CB3 0AS UK
| | - Keshav M Dani
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University Onna Okinawa 904 0495 Japan
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10
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Lloyd-Hughes J, Oppeneer PM, Pereira Dos Santos T, Schleife A, Meng S, Sentef MA, Ruggenthaler M, Rubio A, Radu I, Murnane M, Shi X, Kapteyn H, Stadtmüller B, Dani KM, da Jornada FH, Prinz E, Aeschlimann M, Milot RL, Burdanova M, Boland J, Cocker T, Hegmann F. The 2021 ultrafast spectroscopic probes of condensed matter roadmap. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:353001. [PMID: 33951618 DOI: 10.1088/1361-648x/abfe21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 05/05/2021] [Indexed: 06/12/2023]
Abstract
In the 60 years since the invention of the laser, the scientific community has developed numerous fields of research based on these bright, coherent light sources, including the areas of imaging, spectroscopy, materials processing and communications. Ultrafast spectroscopy and imaging techniques are at the forefront of research into the light-matter interaction at the shortest times accessible to experiments, ranging from a few attoseconds to nanoseconds. Light pulses provide a crucial probe of the dynamical motion of charges, spins, and atoms on picosecond, femtosecond, and down to attosecond timescales, none of which are accessible even with the fastest electronic devices. Furthermore, strong light pulses can drive materials into unusual phases, with exotic properties. In this roadmap we describe the current state-of-the-art in experimental and theoretical studies of condensed matter using ultrafast probes. In each contribution, the authors also use their extensive knowledge to highlight challenges and predict future trends.
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Affiliation(s)
- J Lloyd-Hughes
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom
| | - P M Oppeneer
- Department of Physics and Astronomy, Uppsala University, PO Box 516, S-75120 Uppsala, Sweden
| | - T Pereira Dos Santos
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
| | - A Schleife
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
- Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
- National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
| | - S Meng
- Institute of Physics, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - M A Sentef
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science (CFEL), 22761 Hamburg, Germany
| | - M Ruggenthaler
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science (CFEL), 22761 Hamburg, Germany
| | - A Rubio
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science (CFEL), 22761 Hamburg, Germany
- Nano-Bio Spectroscopy Group and ETSF, Universidad del País Vasco UPV/EHU 20018 San Sebastián, Spain
- Center for Computational Quantum Physics (CCQ), The Flatiron Institute, 162 Fifth Avenue, New York, NY, 10010, United States of America
| | - I Radu
- Department of Physics, Freie Universität Berlin, Germany
- Max Born Institute, Berlin, Germany
| | - M Murnane
- JILA, University of Colorado and NIST, Boulder, CO, United States of America
| | - X Shi
- JILA, University of Colorado and NIST, Boulder, CO, United States of America
| | - H Kapteyn
- JILA, University of Colorado and NIST, Boulder, CO, United States of America
| | - B Stadtmüller
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - K M Dani
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Japan
| | - F H da Jornada
- Department of Materials Science and Engineering, Stanford University, Stanford, 94305, CA, United States of America
| | - E Prinz
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - M Aeschlimann
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - R L Milot
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom
| | - M Burdanova
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom
| | - J Boland
- Photon Science Institute, Department of Electrical and Electronic Engineering, University of Manchester, United Kingdom
| | - T Cocker
- Michigan State University, United States of America
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11
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Kolesnichenko PV, Zhang Q, Zheng C, Fuhrer MS, Davis JA. Multidimensional analysis of excitonic spectra of monolayers of tungsten disulphide: toward computer-aided identification of structural and environmental perturbations of 2D materials. MACHINE LEARNING: SCIENCE AND TECHNOLOGY 2021. [DOI: 10.1088/2632-2153/abd87c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Despite 2D materials holding great promise for a broad range of applications, the proliferation of devices and their fulfillment of real-life demands are still far from being realized. Experimentally obtainable samples commonly experience a wide range of perturbations (ripples and wrinkles, point and line defects, grain boundaries, strain field, doping, water intercalation, oxidation, edge reconstructions) significantly deviating the properties from idealistic models. These perturbations, in general, can be entangled or occur in groups with each group forming a complex perturbation making the interpretations of observable physical properties and the disentanglement of simultaneously acting effects a highly non-trivial task even for an experienced researcher. Here we generalise statistical correlation analysis of excitonic spectra of monolayer WS2, acquired by hyperspectral absorption and photoluminescence imaging, to a multidimensional case, and examine multidimensional correlations via unsupervised machine learning algorithms. Using principal component analysis we are able to identify four dominant components that are correlated with tensile strain, disorder induced by adsorption or intercalation of environmental molecules, multi-layer regions and charge doping, respectively. This approach has the potential to determine the local environment of WS2 monolayers or other 2D materials from simple optical measurements, and paves the way toward advanced, machine-aided, characterization of monolayer matter.
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12
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Gao L, Hu Z, Lu J, Liu H, Ni Z. Defect-related dynamics of photoexcited carriers in 2D transition metal dichalcogenides. Phys Chem Chem Phys 2021; 23:8222-8235. [PMID: 33875990 DOI: 10.1039/d1cp00006c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two-dimensional (2D) transition metal dichalcogenides (TMDs) exhibit enormous potential in the field of optoelectronics. The high performance of TMD materials and optoelectronic devices significantly depends on processes involved in photoelectric conversion, including photo-excitation, relaxation, transportation, and recombination. Remarkably, inevitable defects in materials prolong or shorten the characteristic time of these processes and even bring about new photoelectric conversion channels, namely, the defect-related relaxation pathways of photoexcited carriers tailor the performance of photoelectric applications. In recent years, there have been numerous investigations in exploring the variant transient signals caused by defects in TMDs utilizing ultrafast spectroscopies. They have the capability in providing an accurate and overall representation of ultrafast processes owing to the subtle temporal resolution. The defect-related mechanisms occurring in different time scales (from femtosecond (fs) to microsecond (μs)) play influential roles throughout the relaxation process of photoexcited species. Herein, we review the defect-related relaxation mechanisms of photoexcited species in TMDs according to the time scale utilizing ultrafast spectroscopy techniques. By interpreting and summarizing the defect-related transient signals, we furnish the direction in material design and performance optimization.
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Affiliation(s)
- Lei Gao
- School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China.
| | - Zhenliang Hu
- School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China.
| | - Junpeng Lu
- School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China.
| | - Hongwei Liu
- Jiangsu Key Lab on Opto-Electronic Technology, School of Physics and Technology, Nanjing Normal University, Nanjing 210023, China
| | - Zhenhua Ni
- School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China.
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13
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Hu A, Liu W, Li X, Xu S, Li Y, Xue Z, Tang J, Ye L, Yang H, Li M, Ye Y, Sun Q, Gong Q, Lu G. Spectromicroscopy and imaging of photoexcited electron dynamics at in-plane silicon pn junctions. NANOSCALE 2021; 13:2626-2631. [PMID: 33496300 DOI: 10.1039/d0nr07954e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The ultrafast spatiotemporal imaging of photoexcited electrons is essential to understanding interfacial electron dynamic processes. We used time- and energy-resolved photoemission electron microscopy (PEEM) to investigate the photoexcited electron dynamics at multiplex in-plane silicon pn junctions. We found that the measured kinetic energy of photoelectrons from n-type regions is higher than that from p-type regions owing to different work functions. Interestingly, the kinetic energy of outer n-type regions is higher than that of inner n-type regions, which is caused by the reverse bias induced by photoemission. Time-resolved PEEM results reveal different evolution rates of hot electrons in different doping regions. The rise time of the n-type (outer n-type) regions is faster than that of the p-type (inner n-type) regions. So, closed doping patterns can influence the electron spectra and dynamics at the micro-nano scale. These results help us to understand the ultrafast dynamics of carriers at in-plane interfaces and optimize optoelectronic integrated devices with complex heterojunctions.
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Affiliation(s)
- Aiqin Hu
- State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of the Ministry of Education, School of Physics, Peking University, Beijing 100871, China.
| | - Wei Liu
- State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of the Ministry of Education, School of Physics, Peking University, Beijing 100871, China.
| | - Xiaofang Li
- State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of the Ministry of Education, School of Physics, Peking University, Beijing 100871, China.
| | - Shengnan Xu
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Yaolong Li
- State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of the Ministry of Education, School of Physics, Peking University, Beijing 100871, China.
| | - Zhaohang Xue
- State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of the Ministry of Education, School of Physics, Peking University, Beijing 100871, China.
| | - Jinglin Tang
- State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of the Ministry of Education, School of Physics, Peking University, Beijing 100871, China.
| | - Lulu Ye
- State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of the Ministry of Education, School of Physics, Peking University, Beijing 100871, China.
| | - Hong Yang
- State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of the Ministry of Education, School of Physics, Peking University, Beijing 100871, China. and Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China and Peking University Yangtze Delta Institute of Optoelectronics, Nantong 226010, Jiangsu, China
| | - Ming Li
- Institute of Microelectronics, Peking University, Beijing 100871, China
| | - Yu Ye
- State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of the Ministry of Education, School of Physics, Peking University, Beijing 100871, China.
| | - Quan Sun
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong 226010, Jiangsu, China
| | - Qihuang Gong
- State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of the Ministry of Education, School of Physics, Peking University, Beijing 100871, China. and Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China and Peking University Yangtze Delta Institute of Optoelectronics, Nantong 226010, Jiangsu, China
| | - Guowei Lu
- State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of the Ministry of Education, School of Physics, Peking University, Beijing 100871, China. and Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China and Peking University Yangtze Delta Institute of Optoelectronics, Nantong 226010, Jiangsu, China
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14
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Wittenbecher L, Viñas Boström E, Vogelsang J, Lehman S, Dick KA, Verdozzi C, Zigmantas D, Mikkelsen A. Unraveling the Ultrafast Hot Electron Dynamics in Semiconductor Nanowires. ACS NANO 2021; 15:1133-1144. [PMID: 33439621 PMCID: PMC7877729 DOI: 10.1021/acsnano.0c08101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Hot electron relaxation and transport in nanostructures involve a multitude of ultrafast processes whose interplay and relative importance are still not fully understood, but which are relevant for future applications in areas such as photocatalysis and optoelectronics. To unravel these processes, their dynamics in both time and space must be studied with high spatiotemporal resolution in structurally well-defined nanoscale objects. We employ time-resolved photoemission electron microscopy to image the relaxation of photogenerated hot electrons within InAs nanowires on a femtosecond time scale. We observe transport of hot electrons to the nanowire surface within 100 fs caused by surface band bending. We find that electron-hole scattering substantially influences hot electron cooling during the first few picoseconds, while phonon scattering is prominent at longer time scales. The time scale of cooling is found to differ between the well-defined wurtzite and zincblende crystal segments of the nanowires depending on excitation light polarization. The scattering and transport mechanisms identified will play a role in the rational design of nanostructures for hot-electron-based applications.
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Affiliation(s)
- Lukas Wittenbecher
- Department
of Physics, Lund University, Box 118, 221 00 Lund, Sweden
- Chemical
Physics, Lund University, Box 124, 221 00 Lund, Sweden
- Nano
Lund, Lund University, Box 118, 221 00 Lund, Sweden
| | | | - Jan Vogelsang
- Department
of Physics, Lund University, Box 118, 221 00 Lund, Sweden
- Nano
Lund, Lund University, Box 118, 221 00 Lund, Sweden
| | - Sebastian Lehman
- Department
of Physics, Lund University, Box 118, 221 00 Lund, Sweden
- Nano
Lund, Lund University, Box 118, 221 00 Lund, Sweden
| | - Kimberly A. Dick
- Nano
Lund, Lund University, Box 118, 221 00 Lund, Sweden
- Centre
for Analysis and Synthesis, Lund University, Box 124, 221 00 Lund, Sweden
| | - Claudio Verdozzi
- Department
of Physics, Lund University, Box 118, 221 00 Lund, Sweden
| | - Donatas Zigmantas
- Chemical
Physics, Lund University, Box 124, 221 00 Lund, Sweden
- Nano
Lund, Lund University, Box 118, 221 00 Lund, Sweden
- E-mail:
| | - Anders Mikkelsen
- Department
of Physics, Lund University, Box 118, 221 00 Lund, Sweden
- Nano
Lund, Lund University, Box 118, 221 00 Lund, Sweden
- E-mail:
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15
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Xu C, Yong HW, He J, Long R, Cadore AR, Paradisanos I, Ott AK, Soavi G, Tongay S, Cerullo G, Ferrari AC, Prezhdo OV, Loh ZH. Weak Distance Dependence of Hot-Electron-Transfer Rates at the Interface between Monolayer MoS 2 and Gold. ACS NANO 2021; 15:819-828. [PMID: 33347267 DOI: 10.1021/acsnano.0c07350] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Electron transport across the transition-metal dichalcogenide (TMD)/metal interface plays an important role in determining the performance of TMD-based optoelectronic devices. However, the robustness of this process against structural heterogeneities remains unexplored, to the best of our knowledge. Here, we employ a combination of time-resolved photoemission electron microscopy (TR-PEEM) and atomic force microscopy to investigate the spatially resolved hot-electron-transfer dynamics at the monolayer (1L) MoS2/Au interface. A spatially heterogeneous distribution of 1L-MoS2/Au gap distances, along with the sub-80 nm spatial- and sub-60 fs temporal resolution of TR-PEEM, permits the simultaneous measurement of electron-transfer rates across a range of 1L-MoS2/Au distances. These decay exponentially as a function of distance, with an attenuation coefficient β ∼ 0.06 ± 0.01 Å-1, comparable to molecular wires. Ab initio simulations suggest that surface plasmon-like states mediate hot-electron-transfer, hence accounting for its weak distance dependence. The weak distance dependence of the interfacial hot-electron-transfer rate indicates that this process is insensitive to distance fluctuations at the TMD/metal interface, thus motivating further exploration of optoelectronic devices based on hot carriers.
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Affiliation(s)
- Ce Xu
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Hui Wen Yong
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Jinlu He
- College of Chemistry, Key Laboratory of Theoretical and Computational Photochemistry, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical and Computational Photochemistry, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Alisson R Cadore
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Ioannis Paradisanos
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Anna K Ott
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Giancarlo Soavi
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
- Institute for Solid State Physics, Abbe Center of Photonics, Friedrich-Schiller-University Jena, Max-Wien-Platz 1, 07743 Jena, Germany
| | - Sefaattin Tongay
- School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Giulio Cerullo
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano Italy
- IFN-CNR, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Andrea C Ferrari
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Zhi-Heng Loh
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- Centre for Optical Fibre Technology, The Photonics Institute, Nanyang Technological University, Singapore 639798, Singapore
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16
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Da Browski M, Dai Y, Petek H. Ultrafast Photoemission Electron Microscopy: Imaging Plasmons in Space and Time. Chem Rev 2020; 120:6247-6287. [PMID: 32530607 DOI: 10.1021/acs.chemrev.0c00146] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Plasmonics is a rapidly growing field spanning research and applications across chemistry, physics, optics, energy harvesting, and medicine. Ultrafast photoemission electron microscopy (PEEM) has demonstrated unprecedented power in the characterization of surface plasmons and other electronic excitations, as it uniquely combines the requisite spatial and temporal resolution, making it ideally suited for 3D space and time coherent imaging of the dynamical plasmonic phenomena on the nanofemto scale. The ability to visualize plasmonic fields evolving at the local speed of light on subwavelength scale with optical phase resolution illuminates old phenomena and opens new directions for growth of plasmonics research. In this review, we guide the reader thorough experimental description of PEEM as a characterization tool for both surface plasmon polaritons and localized plasmons and summarize the exciting progress it has opened by the ultrafast imaging of plasmonic phenomena on the nanofemto scale.
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Affiliation(s)
- Maciej Da Browski
- Department of Physics and Astronomy and Pittsburgh Quantum Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.,Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, Devon EX4 4QL, U.K
| | - Yanan Dai
- Department of Physics and Astronomy and Pittsburgh Quantum Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Hrvoje Petek
- Department of Physics and Astronomy and Pittsburgh Quantum Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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17
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Abstract
The microscopic origin and timescale of the fluctuations of the energies of electronic states has a significant impact on the properties of interest of electronic materials, with implication in fields ranging from photovoltaic devices to quantum information processing. Spectroscopic investigations of coherent dynamics provide a direct measurement of electronic fluctuations. Modern multidimensional spectroscopy techniques allow the mapping of coherent processes along multiple time or frequency axes and thus allow unprecedented discrimination between different sources of electronic dephasing. Exploiting modern abilities in coherence mapping in both amplitude and phase, we unravel dissipative processes of electronic coherences in the model system of CdSe quantum dots (QDs). The method allows the assignment of the nature of the observed coherence as vibrational or electronic. The expected coherence maps are obtained for the coherent longitudinal optical (LO) phonon, which serves as an internal standard and confirms the sensitivity of the technique. Fast dephasing is observed between the first two exciton states, despite their shared electron state and common environment. This result is contrary to predictions of the standard effective mass model for these materials, in which the exciton levels are strongly correlated through a common size dependence. In contrast, the experiment is in agreement with ab initio molecular dynamics of a single QD. Electronic dephasing in these materials is thus dominated by the realistic electronic structure arising from fluctuations at the atomic level rather than static size distribution. The analysis of electronic dephasing thereby uniquely enables the study of electronic fluctuations in complex materials.
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18
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Li Y, Liu W, Wang Y, Xue Z, Leng YC, Hu A, Yang H, Tan PH, Liu Y, Misawa H, Sun Q, Gao Y, Hu X, Gong Q. Ultrafast Electron Cooling and Decay in Monolayer WS 2 Revealed by Time- and Energy-Resolved Photoemission Electron Microscopy. NANO LETTERS 2020; 20:3747-3753. [PMID: 32242668 DOI: 10.1021/acs.nanolett.0c00742] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A comprehensive understanding of the ultrafast electron dynamics in two-dimensional transition metal dichalcogenides (TMDs) is necessary for their applications in optoelectronic devices. In this work, we contribute a study of ultrafast electron cooling and decay dynamics in the supported and suspended monolayer WS2 by time- and energy-resolved photoemission electron microscopy (PEEM). Electron cooling in the Q valley of the conduction band is clearly resolved in energy and time, on a time scale of 0.3 ps. Electron decay is mainly via a defect trapping process on a time scale of several picoseconds. We observed that the trap states can be produced and increased by laser illumination under an ultrahigh vacuum, and the higher local optical-field intensity led to the faster increase of trap states. The enhanced defect trapping could significantly modify the carrier dynamics and should be paid attention to in photoemission experiments for two-dimensional materials.
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Affiliation(s)
- Yaolong Li
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Wei Liu
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Yunkun Wang
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Zhaohang Xue
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Yu-Chen Leng
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Aiqin Hu
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Hong Yang
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Yunquan Liu
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Hiroaki Misawa
- Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0021, Japan
- Center for Emergent Functional Matter Science, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Quan Sun
- Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0021, Japan
| | - Yunan Gao
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Xiaoyong Hu
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Qihuang Gong
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
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19
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He J, Fang WH, Long R. Unravelling the effects of oxidation state of interstitial iodine and oxygen passivation on charge trapping and recombination in CH 3NH 3PbI 3 perovskite: a time-domain ab initio study. Chem Sci 2019; 10:10079-10088. [PMID: 32055362 PMCID: PMC6991187 DOI: 10.1039/c9sc02353d] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 09/08/2019] [Indexed: 11/21/2022] Open
Abstract
Understanding nonradiative charge recombination mechanisms is a prerequisite for advancing perovskite solar cells. By performing time-domain density functional theory combined with nonadiabatic (NA) molecular dynamics simulations, we show that electron-hole recombination in perovskites strongly depends on the oxidation state of interstitial iodine and oxygen passivation. The simulations demonstrate that electron-hole recombination in CH3NH3PbI3 occurs within several nanoseconds, agreeing well with experiment. The negative interstitial iodine delays charge recombination by a factor of 1.3. The deceleration is attributed to the fact that interstitial iodine anion forms a chemical bond with its nearest lead atoms, eliminates the trap state, and decreases the NA electron-phonon coupling. The positive interstitial iodine attracts its neighbouring lattice iodine anions, resulting in the formation of an I-trimer and producing an electron trap. Electron trapping proceeds on a very fast timescale, tens of picoseconds, and captures the majority of free electrons available to directly recombine with free holes while inhibiting the recombination of free electrons and holes, delaying the recombination by a factor of 1.5. However, the positive interstitial iodine easily converts to a neutral iodine defect by capturing an electron, giving rise to a singly occupied state above the valence band maximum and acting as a hole trap. The photoexcitation valence band hole becomes trapped by the hole trap state very rapidly, followed by acceleration of recombination with the conduction band free electron by a factor of 1.6. Surprisingly, molecular oxygen interacting with interstitial iodine anion forms a stable IO3 -1 species, which inhibits ion migration, stabilizes perovskites, and suppresses the electron-hole recombination by a factor of 2.7. Our simulations reveal the microscopic effects of the oxidation state of interstitial iodine defects and oxygen passivation in perovskites, suggesting an effective way to improve perovskite photovoltaic and optoelectronic devices.
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Affiliation(s)
- Jinlu He
- College of Chemistry , Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education , Beijing Normal University , Beijing , 100875 , P. R. China .
| | - Wei-Hai Fang
- College of Chemistry , Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education , Beijing Normal University , Beijing , 100875 , P. R. China .
| | - Run Long
- College of Chemistry , Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education , Beijing Normal University , Beijing , 100875 , P. R. China .
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20
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Huber B, Pres S, Wittmann E, Dietrich L, Lüttig J, Fersch D, Krauss E, Friedrich D, Kern J, Lisinetskii V, Hensen M, Hecht B, Bratschitsch R, Riedle E, Brixner T. Space- and time-resolved UV-to-NIR surface spectroscopy and 2D nanoscopy at 1 MHz repetition rate. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:113103. [PMID: 31779407 DOI: 10.1063/1.5115322] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 10/16/2019] [Indexed: 06/10/2023]
Abstract
We describe a setup for time-resolved photoemission electron microscopy with aberration correction enabling 3 nm spatial resolution and sub-20 fs temporal resolution. The latter is realized by our development of a widely tunable (215-970 nm) noncollinear optical parametric amplifier (NOPA) at 1 MHz repetition rate. We discuss several exemplary applications. Efficient photoemission from plasmonic Au nanoresonators is investigated with phase-coherent pulse pairs from an actively stabilized interferometer. More complex excitation fields are created with a liquid-crystal-based pulse shaper enabling amplitude and phase shaping of NOPA pulses with spectral components from 600 to 800 nm. With this system we demonstrate spectroscopy within a single plasmonic nanoslit resonator by spectral amplitude shaping and investigate the local field dynamics with coherent two-dimensional (2D) spectroscopy at the nanometer length scale ("2D nanoscopy"). We show that the local response varies across a distance as small as 33 nm in our sample. Further, we report two-color pump-probe experiments using two independent NOPA beamlines. We extract local variations of the excited-state dynamics of a monolayered 2D material (WSe2) that we correlate with low-energy electron microscopy (LEEM) and reflectivity measurements. Finally, we demonstrate the in situ sample preparation capabilities for organic thin films and their characterization via spatially resolved electron diffraction and dark-field LEEM.
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Affiliation(s)
- Bernhard Huber
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Sebastian Pres
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Emanuel Wittmann
- Lehrstuhl für BioMolekulare Optik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 München, Germany
| | - Lysanne Dietrich
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Julian Lüttig
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Daniel Fersch
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Enno Krauss
- NanoOptics & Biophotonics Group, Experimental Physics 5, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Daniel Friedrich
- NanoOptics & Biophotonics Group, Experimental Physics 5, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Johannes Kern
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany
| | - Victor Lisinetskii
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Matthias Hensen
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Bert Hecht
- NanoOptics & Biophotonics Group, Experimental Physics 5, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Rudolf Bratschitsch
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany
| | - Eberhard Riedle
- Lehrstuhl für BioMolekulare Optik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 München, Germany
| | - Tobias Brixner
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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