卤化物
光致发光
钙钛矿(结构)
载流子
材料科学
化学物理
硅
存水弯(水管)
光电子学
化学
无机化学
结晶学
环境工程
工程类
作者
Alexander J. Knight,Adam D. Wright,Jay B. Patel,David P. McMeekin,Henry J. Snaith,Michael B. Johnston,Laura M. Herz
出处
期刊:ACS energy letters
[American Chemical Society]
日期:2018-11-27
卷期号:4 (1): 75-84
被引量:213
标识
DOI:10.1021/acsenergylett.8b02002
摘要
An understanding of the factors driving halide segregation in lead mixed-halide perovskites is required for their implementation in tandem solar cells with existing silicon technology. Here we report that the halide segregation dynamics observed in the photoluminescence from CH3NH3Pb(Br0.5I0.5)3 is strongly influenced by the atmospheric environment, and that encapsulation of films with a layer of poly(methyl methacrylate) allows for halide segregation dynamics to be fully reversible and repeatable. We further establish an empirical model directly linking the amount of halide segregation observed in the photoluminescence to the fraction of charge carriers recombining through trap-mediated channels, and the photon flux absorbed. From such quantitative analysis we show that under pulsed illumination, the frequency of the modulation alone has no influence on the segregation dynamics. Additionally, we extrapolate that working CH3NH3Pb(Br0.5I0.5)3 perovskite cells would require a reduction of the trap-related charge carrier recombination rate to ≲105s–1 in order for halide segregation to be sufficiently suppressed.
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