Pressure-Driven Reverse Intersystem Crossing: New Path toward Bright Deep-Blue Emission of Lead-Free Halide Double Perovskites

• DOI: 10.1021/jacs.1c06207
• Publication Date: 2021-09-10T20:30:35Z
• Authors: Zhiwei Ma; Qian Li; Jiajun Luo; Shunran Li; Laizhi Sui; Dianlong Zhao; Kaijun Yuan; Guanjun Xiao; Jiang Tang; Zewei Quan; Bo Zou
• Keywords: Intersystem crossing

Maximizing the regeneration of singlet excitons remains a considerable challenge in deep-blue emission systems to obtain low-cost, high-efficiency fluorescent materials. However, formation long-lifetime triplet generally dominates radiative process, making it greatly difficult harvest with high color purity because depression excitons. Here, very bright double perovskite Cs2Na0.4Ag0.6InCl6 alloyed Bi doping (CNAICB) was successfully achieved by pressure-driven reverse intersystem crossing (RISC), an abnormal photophysical process energy transfer from excited state back singlet. Therein, inherently broad CNAICB associated self-trapped (STEs) at states, whereas recombination STEs populated states responsible for observed emission. Moreover, corresponds Commission Internationale de L'Eclairage (CIE) coordinates (0.16, 0.06) 5.01 GPa, which meets requirement Rec. 2020 display standards. Likewise, pressure introduced as efficient tool rule out possibility free and clarify long-standing conventional dispute over origin low-wavelength Cs2AgInCl6. Our study not only demonstrates that can be robust means boost but also provides deep insights into structure-property relationship lead-free perovskites.