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Wu XG, Sun S, Song T, Zhang X, Wang C, Yang Y, Wang S, Zhong H. Revealing the vertical structure of in-situ fabricated perovskite nanocrystals films toward efficient pure red light-emitting diodes. FUNDAMENTAL RESEARCH 2024; 4:362-368. [PMID: 38933501 PMCID: PMC11197484 DOI: 10.1016/j.fmre.2022.05.004] [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: 03/01/2022] [Revised: 04/29/2022] [Accepted: 05/06/2022] [Indexed: 10/18/2022] Open
Abstract
The development of efficient perovskite light-emitting diodes (PeLEDs) relies strongly on the fabrication of perovskite films with rationally designed structures (grain size, composition, surface, etc.). Therefore, an understanding of structure-performance relationships is of vital importance for developing high-performance perovskite devices, particularly for devices with in-situ fabricated perovskite nanocrystal films. In this study, we reveal the vertical structure of an in-situ fabricated quasi-two-dimensional perovskite film. By combining time-of-flight secondary ion mass spectrometry, energy dispersive spectroscopy, grazing incidence wide-angle X-ray scattering (GIWAXS), and low-temperature photoluminescence spectra, we illustrate that the resulting in-situ fabricated DPPA2Csn-1Pbn(Br0.3I0.7)3n+1 (DPPA+: 3,3-diphenylpropylammonium) film has a gradient structure with a very thin layer of ligands on the surface, predominantly small-n domains at the top, and predominantly large-n domains at the bottom owing to the solubility difference of the precursors. In addition, GIWAXS measurements show that the domain of n = 2 on the top layer has an ordered in-plane alignment. Based on the understanding of the film structure, we developed an in-situ fabrication process with ligand exchange to achieve efficient pure red PeLEDs at 638 nm with an average external quantum efficiency (EQE) of 7.4%. The optimized device had a maximum luminance of 623 cd/m2 with a peak EQE of 9.7%.
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Affiliation(s)
- Xian-gang Wu
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Shipei Sun
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Tinglu Song
- Experimental Center of Advanced Materials, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Xin Zhang
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Chenhui Wang
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yingguo Yang
- Shanghai Synchrotron Radiation Facility (SSRF), Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China
| | - Shuangpeng Wang
- Institute of Applied Physics and Materials Engineering, University of Macau, Macau 999078, China
| | - Haizheng Zhong
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, China
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Ma C, Xu F, Song T. Dual-Layered Interfacial Evolution of Lithium Metal Anode: SEI Analysis via TOF-SIMS Technology. ACS APPLIED MATERIALS & INTERFACES 2022; 14:20197-20207. [PMID: 35470659 DOI: 10.1021/acsami.2c00842] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Lithium metal battery has been considered as one of the most promising candidates for the next generation of energy storage systems due to its high energy density. However, the lithium metal may react with the electrolyte, resulting in the instability of the solid/liquid interface. The solid electrolyte interface (SEI) layer was found to affect the interface stability of the lithium metal anode; the real structure of SEI couldn't be accurately analyzed so far. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) has been thought as a powerful tool to carry out three-dimensional (3D) characterization and structural reconstruction at a high-resolution nanoscale, as well as detect ionized elements and molecule fragments at the ppb level due to its excellent sensitivity. Herein, we employed TOF-SIMS to investigate the chemical composition of SEI at the surface of the lithium metal anode after electrochemical cycles. We find that SEI is not a completely dense interface layer. The organic phase of SEI can accommodate part of the electrolyte, enhancing the lithium-ion conductivity. Meanwhile, SEI is an interface layer that changes with the state of the electrolyte, and this process of change is expressed by conventional characterization methods. However, the distribution of lithium salt can be analyzed by TOF-SIMS to judge the change degree of SEI. Our work provides significant guidance for accurately characterizing the SEI layer, as well as constructing a more realistic interface layer model.
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Affiliation(s)
- Chengwei Ma
- Beijing Key Laboratory of Environmental Science and Engineering, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, P. R. China
| | - Fan Xu
- BTR New Material Group Co., Ltd., Shenzhen 518107, P. R. China
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 P. R. China
| | - Tinglu Song
- Experimental Center of Advanced Materials School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, P. R. China
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