Many-body interactions in photo-excited lead iodide perovskite
Many-body interactions in photo-excited lead iodide perovskite
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DOI：
10.1039/c5ta01093d
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发表时间：
2015-01-01
影响因子：
11.9
通讯作者：
Zhu, X-Y
中科院分区：
文献类型：
--
作者：
Trinh, M. Tuan;Wu, Xiaoxi;Zhu, X-Y
卤化铅钙钛矿是一种很有前途的薄膜太阳能电池半导体材料。尽管近年来进行了大量的光物理研究，但卤化铅钙钛矿的光激发性质仍然是一个有争议的话题。在这里，我们使用瞬态吸收光谱来重新检查卤化铅钙钛矿薄膜，已经报道了非常高的太阳能电池效率。我们关注的多体相互作用表现在：(1)热载流子对随后的e-h对产生的瞬态Stark效应；(2)由三体载流子-载流子相互作用引起的俄歇复合。这些观察结果证实了卤化铅钙钛矿中自由载流子在以上带隙激发下的优势。我们还建议对载流子进行有效的动态筛选，这可能是由于钙钛矿晶格中甲基铵阳离子的取向自由，以及在氯前驱体存在下生长的卤化铅钙钛矿薄膜中存在可忽略不计的载流子捕获。
Lead halide perovskite is emerging as a promising semiconductor material for thin film solar cells. Despite a large number of recent photophysical studies, the nature of photo-excitation in lead halide perovskite remains a subject of debate. Here we use transient absorption spectroscopy to re-examine lead halide perovskite thin films that have been reported to give very high solar cell efficiencies. We focus on many-body interactions that are manifested in (1) the transient Stark effect exerted by hot carriers on subsequent e-h pair generation; and (2) the Auger recombination due to three-body carrier-carrier interactions. These observations establish the dominance of free carriers from above band-gap excitation in lead halide perovskite. We also suggest the effective dynamic screening of charge carriers, likely due to orientational freedom of methylammonium cations in the perovskite lattice, and the presence of negligible charge carrier trapping in lead halide perovskite thin films grown in the presence of chloride precursors.