Formamidinium Lead Halide Perovskite Crystals with Unprecedented Long Carrier Dynamics and Diffusion Length
Formamidinium Lead Halide Perovskite Crystals with Unprecedented Long Carrier Dynamics and Diffusion Length
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DOI：
10.1021/acsenergylett.6b00002
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发表时间：
2016-07-01
影响因子：
22
通讯作者：
Bakr, Osman M.
中科院分区：
文献类型：
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作者：
Zhumekenov, Ayan A.;Saidaminov, Makhsud I.;Bakr, Osman M.
通过在钙钛矿多晶薄膜中用甲脒（FA）代替甲基铵（MA），实现了具有创纪录效率的最先进的钙钛矿太阳能电池。然而，这些薄膜遭受严重的结构紊乱和高密度的陷阱，因此，FA基钙钛矿的固有特性仍然模糊。本文报道了FAPbX（3）（X = Br-和I-）单晶的详细光学和电学性质。FAPbX（3）晶体不仅与FAPbX（3）多晶膜相比，而且令人惊讶地与MAPbX（3）单晶相比，都表现出显著增强的传输。特别地，FAPbBr（3）晶体显示出比MAPbBr（3）单晶长5倍的载流子寿命和低10倍的暗载流子浓度。我们报道了长的载流子扩散长度-比以前认为的长得多-FAPbI（3）晶体为6.6 μ m，FAPbBr（3）晶体为19.0 μ m，后者是钙钛矿材料中报道的最长值之一。这些发现对于钙钛矿的未来综合应用具有重要意义。
State-of-the-art perovskite solar cells with record efficiencies were achieved by replacing methylammonium (MA) with formamidinium (FA) in perovskite polycrystalline films. However, these films suffer from severe structural disorder and high density of traps; thus, the intrinsic properties of FA-based perovskites remain obscured. Here we report the detailed optical and electrical properties of FAPbX(3) (where X = Br- and I-) single crystals. FAPbX(3) crystals exhibited markedly enhanced transport compared not just to FAPbX(3) polycrystalline films but also, surprisingly, to MAPbX(3) single crystals. Particularly, FAPbBr(3) crystals displayed a 5-fold longer carrier lifetime and 10-fold lower dark carrier concentration than those of MAPbBr(3) single crystals. We report long carrier diffusion lengths-much longer than previously thought-of 6.6 mu m for FAPbI(3) and 19.0 mu m for FAPbBr(3) crystals, the latter being one of the longest reported values in perovskite materials. These findings are of great importance for future integrated applications of these perovskites.