Angew. Chem.: Two-dimensional perovskite with long afterglow color tunable and its luminescent mechanism

• Two-dimensional (2D)-halide perovskites have promising applications in photodetectors, solar cells, and phosphorescence systems due to their diverse chemical structures and excellent environmental stability. However, the low singlet-to-triplet conversion efficiency in 2D hybrid halide perovskites makes the phosphorescent lifetime very short, and the organic sites are easily decomposed under the environment of oxygen, water, temperature, etc., which limits its further application.

  
  

  Professor Yu Xue from Chengdu University and researcher Wang Ting from Chengdu University of Technology cooperated to study Cs2CdCl4 perovskite based on 2D Ruddlesden-Popper phase, and found that it has a self-assembled interlayer corridor structure, which is easy to introduce trap centers, thus realizing 2D halogenation Perovskites have long afterglow luminescence. The ion doping strategy introduces new luminescent centers, and regulates the distribution of trap energy levels, prolonging the afterglow time, realizing the effective adjustment of long-lasting luminescent color, and improving its thermal stability.

  
  

  This work provides a way of thinking for the research of low-dimensional perovskite long afterglow materials, and the various encryption modes produced show the application prospect in advanced anti-counterfeiting. These research results will help to further improve the application performance and environmental stability of 2D halide perovskites in optoelectronics and energy fields.

  
  
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• (a) Schematic diagram of the structure of Cs2CdCl4:Mn2+. (b) Photoluminescence spectra of Cs2CdCl4 and (d) Cs2CdCl4:xMn2+.
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• (a) LPL spectra of Cs2CdCl4 and Cs2CdCl4:0.2Mn2+. (b) LPL decay time curves of Cs2CdCl4 and Cs2CdCl4:0.2Mn2+. (c) Time-correlated LPL images of Cs2CdCl4 and Cs2CdCl4:0.2Mn2+. (d) TL curves of Cs2CdCl4 and Cs2CdCl4:0.2Mn2+. (e) Schematic diagram of the LPL luminescence mechanism of Cs2CdCl4:0.2Mn2+.

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• Temperature-dependent PL spectra of (a) Cs2CdCl4 and (b) Cs2CdCl4:0.2Mn2+. (c) Temperature-dependent PL images of Cs2CdCl4 and Cs2CdCl4:0.2Mn2+.

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• Schematic diagram of the multi-color anti-counterfeiting application of Cs2CdCl4 and Cs2CdCl4:xMn2+ under various conditions (excitation wavelength, temperature, different Mn2+ ion doping concentration, time scale).

• Ya Liu, Shuangpeng Yan, Tianchi Wang, Qingshan He, Xiaodie Zhu, Chao Wang, Daiyuan Liu, Ting Wang,* Xuhui Xu, Xue Yu* 

  Angewandte Chemie International Edition
  

  ANIE202308420
  

  
  

  https://doi.org/10.1002/anie.202308420