National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
Nanoscale. 2017 Jun 8;9(22):7391-7396. doi: 10.1039/c7nr01287j.
In recent years, there has been an unprecedented rise in the research of halide perovskites because of their important optoelectronic applications, including photovoltaic cells, light-emitting diodes, photodetectors and lasers. The most pressing question concerns the stability of these materials. Here faster degradation and PL quenching are observed at higher iodine content for mixed-halide perovskite CsPb(BrI) nanocrystals, and a simple yet effective method is reported to significantly enhance their stability. After selective etching with acetone, surface iodine is partially etched away to form a bromine-rich surface passivation layer on mixed-halide perovskite nanocrystals. This passivation layer remarkably stabilizes the nanocrystals, making their PL intensity improved by almost three orders of magnitude. It is expected that a similar passivation layer can also be applied to various other kinds of perovskite materials with poor stability issues.
近年来，卤化物钙钛矿因其在光电应用方面的重要性，包括光伏电池、发光二极管、光电探测器和激光器，引起了前所未有的研究热潮。最紧迫的问题是这些材料的稳定性。在这里，对于混合卤化物钙钛矿 CsPb(BrI)纳米晶体，观察到碘含量较高时会更快地降解和 PL 猝灭，并且报道了一种简单而有效的方法来显著提高其稳定性。用丙酮选择性刻蚀后，表面碘部分被刻蚀掉，在混合卤化物钙钛矿纳米晶体上形成富含溴的表面钝化层。这种钝化层显著稳定了纳米晶体，使它们的 PL 强度提高了近三个数量级。预计类似的钝化层也可以应用于其他各种稳定性较差的钙钛矿材料。
