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Sun C, Zhou H, Sheng T, Li S, Zhu H. Ultrafast Interlayer Charge Transfer Outcompeting Intralayer Valley Relaxation in Few-Layer 2D Heterostructures. ACS NANO 2024; 18:931-938. [PMID: 38154000 DOI: 10.1021/acsnano.3c09681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2023]
Abstract
While 2D transition metal dichalcogenides (TMDs) feature interesting layer-tunable multivalley band structures, their preeminent role in determining the photoexcitation charge transfer dynamics in 2D heterostructures (HSs) is yet to be unraveled, as previous charge transfer studies on TMD HSs have been mostly focused on monolayers with a direct bandgap at the K valley. By ultrafast transient absorption spectroscopy and deliberately designed few-layer WSe2/WS2 HSs, we have observed an ultrafast interlayer electron transfer from photoexcited few-layer WSe2 to WS2, prior to intralayer relaxation to lower lying dark valleys. More interestingly, we have identified an unconventional ∼0.5 ps electron back-transfer process after the initial interlayer electron transfer in HSs with WSe2 layers ≥ 3, regenerating indirect intralayer excitons. The result reveals an ielectron and valley relaxation pathway mediated by interlayer charge transfer in 2D HSs, faster than intralayer relaxation. It also sheds light on the origin of generally observed robust ultrafast interlayer charge transfer in TMD HSs and provides guidance toward optoelectronic and valleytronic devices using few-layer TMDs.
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Affiliation(s)
- Cheng Sun
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang, China, 310027
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, Zhejiang, China, 311215
| | - Hongzhi Zhou
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang, China, 310027
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, Zhejiang, China, 311215
| | - Tianyu Sheng
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang, China, 310027
| | - Shuangshuang Li
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang, China, 310027
| | - Haiming Zhu
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang, China, 310027
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, Zhejiang, China, 311215
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Kim W, Jeong G, Oh J, Kim J, Watanabe K, Taniguchi T, Ryu S. Exciton-Sensitized Second-Harmonic Generation in 2D Heterostructures. ACS NANO 2023; 17:20580-20588. [PMID: 37801328 DOI: 10.1021/acsnano.3c07428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
The efficient optical second-harmonic generation (SHG) of two-dimensional (2D) crystals, coupled with their atomic thickness, which circumvents the phase-match problem, has garnered considerable attention. While various 2D heterostructures have shown promising applications in photodetectors, switching electronics, and photovoltaics, the modulation of nonlinear optical properties in such heterosystems remains unexplored. In this study, we investigate exciton-sensitized SHG in heterobilayers of transition metal dichalcogenides (TMDs), where photoexcitation of one donor layer enhances the SHG response of the other as an acceptor. We utilize polarization-resolved interferometry to detect the SHG intensity and phase of each individual layer, revealing the energetic match between the excitonic resonances of donors and the SHG enhancement of acceptors for four TMD combinations. Our results also uncover the dynamic nature of interlayer coupling, as made evident by the dependence of sensitization on interlayer gap spacing and the average power of the fundamental beam. This work provides insights into how the interlayer coupling of two different layers can modify nonlinear optical phenomena in 2D heterostructures.
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Affiliation(s)
- Wontaek Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 37673, Korea
| | - Gyouil Jeong
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 37673, Korea
| | - Juseung Oh
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 37673, Korea
| | - Jihun Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 37673, Korea
| | - Kenji Watanabe
- Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Sunmin Ryu
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 37673, Korea
- Institute for Convergence Research and Education in Advanced Technology (I-CREATE), Yonsei University, Seoul 03722, Korea
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Jia Q, Wang C, Liu J, Cai X, Zhong L, Chen S, Li T, Yu G, Wu LZ, Duan D. Synergistic Effect of Sr-O Divacancy and Exposing Facets in SrTiO 3 Micro/Nano Particle: Accelerating Exciton Formation and Splitting, Highly Efficient Co 2+ Photooxidation. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2202659. [PMID: 36059245 DOI: 10.1002/smll.202202659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/17/2022] [Indexed: 06/15/2023]
Abstract
As a typical perovskite-type crystal, polyhedral strontium titanate (SrTiO3 ) has shown anisotropic charge transport behavior in recent studies, however, the carrier transportation and transition of which has not been explained very clearly. This work present the existence of Sr and O divacancies in the novel rhombicuboctahedron SrTiO3 micro/nano particles (Sr1- x TiO3- x /TiO2- x ) with exposing (100), (110) and (111) facets and the diameter of 300-700 nm synthesized via hydrothermal synthesis, and also summarizes the dissociation mechanism of self-trapped excitons (STEs) caused by the divacancy and facet effect. In addition, most importantly, the metastable STEs with ultra-low binding energy (Eb < 3 meV) under illumination are discovered. Combining the model of S-scheme heterojunction, a conversion mechanism of photoinduced carriers is proposed. The photocatalytic reaction of Co2+ is used as the probe reaction, and the unique Sr1- x TiO3- x /TiO2- x possesses a high photooxidation efficiency of Co2+ , by which 70.3% of Co2+ is oxidized to Co3+ (CoOOH) in 5 min. This finding may provide a guideline for an optimal design of the photocatalytic materials for the recovery and extraction of metal ions based on SrTiO3 .
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Affiliation(s)
- Qibo Jia
- CAS Key Laboratory of Green Process and Engineering, National Engineering Research Center of Green Recycling for Strategic Metal Resources, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Chuyu Wang
- CAS Key Laboratory of Green Process and Engineering, National Engineering Research Center of Green Recycling for Strategic Metal Resources, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Jian Liu
- CAS Key Laboratory of Green Process and Engineering, National Engineering Research Center of Green Recycling for Strategic Metal Resources, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Xiaojiao Cai
- CAS Key Laboratory of Green Process and Engineering, National Engineering Research Center of Green Recycling for Strategic Metal Resources, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Li Zhong
- CAS Key Laboratory of Green Process and Engineering, National Engineering Research Center of Green Recycling for Strategic Metal Resources, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Siming Chen
- CAS Key Laboratory of Green Process and Engineering, National Engineering Research Center of Green Recycling for Strategic Metal Resources, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Ting Li
- CAS Key Laboratory of Green Process and Engineering, National Engineering Research Center of Green Recycling for Strategic Metal Resources, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Gangqiang Yu
- Faculty of Environment and Life, Beijing University of Technology, Beijing, 100124, P. R. China
| | - Li-Zhu Wu
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Dongping Duan
- CAS Key Laboratory of Green Process and Engineering, National Engineering Research Center of Green Recycling for Strategic Metal Resources, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
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Zhang C, Lu G, Zhang Y, Fang Z, He H, Zhu H. Long-range transport and ultrafast interfacial charge transfer in perovskite/monolayer semiconductor heterostructure for enhanced light absorption and photocarrier lifetime. J Chem Phys 2022; 156:244701. [DOI: 10.1063/5.0097617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Atomically thin two-dimensional transition metal dichalcogenides (TMDs) have shown great potential for optoelectronic applications, including photodetectors, phototransistors, and spintronic devices. However, the applications of TMD-based optoelectronic devices are severely restricted by their weak light absorption and short exciton lifetime due to their atomically thin nature and strong excitonic effect. To simultaneously enhance the light absorption and photocarrier lifetime of monolayer semiconductors, here, we report 3D/2D perovskite/TMD type II heterostructures by coupling solution processed highly smooth and ligand free CsPbBr3 film with MoS2 and WS2 monolayers. By time-resolved spectroscopy, we show interfacial hole transfer from MoS2 (WS2) to the perovskite layer occurs in an ultrafast time scale (100 and 350 fs) and interfacial electron transfer from ultrathin CsPbBr3 to MoS2 (WS2) in ∼3 (9) ps, forming a long-lived charge separation with a lifetime of >20 ns. With increasing CsPbBr3 thickness, the electron transfer rate from CsPbBr3 to TMD is slower, but the efficiency remains to be near-unity due to coupled long-range diffusion and ultrafast interfacial electron transfer. This study indicates that coupling solution processed lead halide perovskites with strong light absorption and long carrier diffusion length to monolayer semiconductors to form a type II heterostructure is a promising strategy to simultaneously enhance the light harvesting capability and photocarrier lifetime of monolayer semiconductors.
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Affiliation(s)
- Chi Zhang
- State Key Laboratory of Modern Optical Instrumentation, Key Laboratory of Excited-State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Guochao Lu
- School of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, China
| | - Yao Zhang
- State Key Laboratory of Modern Optical Instrumentation, Key Laboratory of Excited-State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Zhishan Fang
- School of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, China
| | - Haiping He
- School of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, China
| | - Haiming Zhu
- State Key Laboratory of Modern Optical Instrumentation, Key Laboratory of Excited-State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, Zhejiang 311200, China
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Ye C, Yang Z, Dong J, Huang Y, Song M, Sa B, Zheng J, Zhan H. Layer-Tunable Nonlinear Optical Characteristics and Photocarrier Dynamics of 2D PdSe 2 in Broadband Spectra. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2103938. [PMID: 34677904 DOI: 10.1002/smll.202103938] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/30/2021] [Indexed: 06/13/2023]
Abstract
Layered 2D transition metal dichalcogenides (TMDCs) exhibited fascinating nonlinear optical (NLO) properties for constructing varied promising optoelectronics. However, exploring the desired 2D materials with both superior nonlinear absorption and ultrafast response in broadband spectra remain the key challenges to harvest their greatest potential. Here, based on synthesizing 2D PdSe2 films with the controlled layer number, the authors systematically demonstrated the broadband giant NLO performance and ultrafast excited carrier dynamics of this emerging material under femtosecond visible-to-near-infrared laser-pulse excitation (400-1550 nm). Layer-dependent and wavelength-dependent evolution of optical bandgap, nonlinear absorption, and photocarrier dynamics in the obtained 2D PdSe2 are clearly revealed. Specially, the transition from semiconducting to semimetallic PdSe2 induced dramatic changes of their interband absorption-relaxation process. This work makes 2D PdSe2 more competitive for future ultrafast photonics and also opens up a new avenue for the optical performance optimization of various 2D materials by rational design of these materials.
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Affiliation(s)
- Chenyu Ye
- College of Materials Science and Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Zhenqi Yang
- College of Materials Science and Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Junhao Dong
- College of Materials Science and Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Yongfeng Huang
- College of Materials Science and Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Miaomiao Song
- College of Materials Science and Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Baisheng Sa
- College of Materials Science and Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Jingying Zheng
- College of Materials Science and Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Hongbing Zhan
- College of Materials Science and Engineering, Fuzhou University, Fuzhou, 350108, China
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