通过溴碘比调节无铅钙钛矿纳米晶的荧光特性

Control Fluorescence Emissions of Lead-Free Perovskite Nanocrystals by Adjusting Content Ratio Br to I

摘要:

卤化物钙钛矿化合物作为具有可调特性的半导体材料引起了人们的兴趣，由于其加工方式廉价，使其在电子领域中有巨大的应用潜力。然而，铅的毒性仍然阻碍了卤化物钙钛矿化合物的实际应用，因此亟需开发无铅卤化物钙钛矿。采用配体辅助沉积法，在室温下制备了Cs₃Bi₂(I_xBr_1-x)₉（x=1、0.9、0.7、0.5、0.3和0.1）钙钛矿纳米晶，并通过调节溴碘比，调节了钙钛矿纳米晶的波长。所制备的纳米晶属于六方晶系，通过X射线衍射仪可以发现，随着Br离子添加量的增加，Cs₃Bi₂(I_xBr_1-x)₉的晶体结构逐渐发生转变；荧光光谱和Commission Internationale de l′Eclairage图谱显示，通过调节溴碘比，Cs₃Bi₂(I_xBr_1-x)₉荧光发射从绿色逐渐转变为蓝色，实现了蓝绿范围内连续的光谱调节。上述方法为无铅全无机钙钛矿纳米晶体的快速阴离子交换，提供了一种新的方案。

Abstract:

Halide perovskite compounds have attracted people's interest as semiconductors with adjustable characteristics， and their processing methods are cheap， which makes them have great application potential in the electronic field. However， the toxicity of Pb still hinders the practical application of halide perovskite compounds. Therefore， we strive to develop lead-free halide perovskite. Cs₃Bi₂（I_xBr_1-x）₉ （x=1， 0.9， 0.7， 0.5， 0.3 and 0.1） perovskite nanocrystals were prepared by ligand-assisted deposition at room temperature. Adjusting the content ratio of Br to I could tune the fluorescence emission emitted by Cs₃Bi₂（I_xBr_1-x）₉. Cs₃Bi₂（I_xBr_1-x）₉ perovskite nanocrystals belong to hexagonal， and the crystal structure changes from Cs₃Bi₂I₉ to Cs₃Bi₂Br₉ with the increased content of Br ions. Fluorescence and commission internationale de l′eclairage spectra showed that the fluorescence emissions of Cs₃Bi₂（I_xBr_1-x）₉ changed from green to blue by adjusting ratio of Br to I， achieving continuous spectral regulation in the blue-green range. This method provides a new method for rapid anion exchange of all inorganic lead-free perovskite nanocrystals.