Extended carrier lifetimes and diffusion in hybrid perovskites revealed by Hall effect and photoconductivity measurements.
Extended carrier lifetimes and diffusion in hybrid perovskites revealed by Hall effect and photoconductivity measurements.
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DOI：
10.1038/ncomms12253
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发表时间：
2016-08-01
影响因子：
16.6
通讯作者：
Podzorov V
中科院分区：
文献类型：
--
作者：
Chen Y;Yi HT;Wu X;Haroldson R;Gartstein YN;Rodionov YI;Tikhonov KS;Zakhidov A;Zhu XY;Podzorov V
近年来报道的混合钙钛矿太阳能电池的令人印象深刻的性能仍然有待对其微观起源的全面理解。在这项工作中，本征霍尔迁移率和光生载流子复合系数直接测量在这些材料中的稳态输运研究。结果表明，杂化钙钛矿中的电子空穴复合率和载流子俘获率都很低。双分子复合系数（10−11至10−10 cm 3 s−1）与最好的直接带无机半导体相当，尽管混合钙钛矿中的固有霍尔迁移率相当低（高达60 cm 2 V−1 s−1）。在这里测量，稳态载流子寿命（高达3 ms）和扩散长度（长达650 μm）明显长于高纯度晶体无机半导体。我们认为，这些实验结果是一致的极化性质的电荷载流子，从相互作用的电荷与甲基铵偶极子。 混合钙钛矿表现出长的载流子扩散长度和寿命。在这里，Chen等人通过实验表明，钙钛矿中的载流子复合远离朗之万，而更接近最好的直接带隙半导体，这可以通过电荷载流子的偶极极化性质来解释。
Impressive performance of hybrid perovskite solar cells reported in recent years still awaits a comprehensive understanding of its microscopic origins. In this work, the intrinsic Hall mobility and photocarrier recombination coefficient are directly measured in these materials in steady-state transport studies. The results show that electron-hole recombination and carrier trapping rates in hybrid perovskites are very low. The bimolecular recombination coefficient (10−11 to 10−10 cm3 s−1) is found to be on par with that in the best direct-band inorganic semiconductors, even though the intrinsic Hall mobility in hybrid perovskites is considerably lower (up to 60 cm2 V−1 s−1). Measured here, steady-state carrier lifetimes (of up to 3 ms) and diffusion lengths (as long as 650 μm) are significantly longer than those in high-purity crystalline inorganic semiconductors. We suggest that these experimental findings are consistent with the polaronic nature of charge carriers, resulting from an interaction of charges with methylammonium dipoles. Hybrid perovskites exhibit long carrier diffusion lengths and lifetimes. Here, Chen et al. show experimentally that carrier recombination in perovskites is far from Langevin and closer to the best direct-bandgap semiconductors, which can be explained by the dipolar polaronic nature of charge carriers.