Anomalous Dielectric Behavior of a Pb/Sn Perovskite: Effect of Trapped Charges on Complex Photoconductivity
Anomalous Dielectric Behavior of a Pb/Sn Perovskite: Effect of Trapped Charges on Complex Photoconductivity
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DOI：
10.1021/acsphotonics.8b00422
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发表时间：
2018-06
期刊：
影响因子：
7
通讯作者：
Kento Yamada;Ryosuke Nishikubo;Hikaru Oga;Y. Ogomi;S. Hayase;S. Kanno;Y. Imamura;M. Hada;A. Saeki
中科院分区：
文献类型：
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作者：
Kento Yamada;Ryosuke Nishikubo;Hikaru Oga;Y. Ogomi;S. Hayase;S. Kanno;Y. Imamura;M. Hada;A. Saeki
有机-无机金属卤化物钙钛矿（MHP）具有优异的电学和光学性能，有利于太阳能电池和发光二极管的性能。然而，这些材料的介电性能仍然知之甚少，尽管可能影响延迟电荷复合和器件电容。在此，我们表征了前所未有的MHP的介电行为，包括甲基铵阳离子，Pb/Sn作为金属，和Br/I作为卤化物使用时间分辨微波电导率（TRMC）测量。在特定组成下，上述MHP表现出负的真实的和正的虚光电导性，其极性与常规光生电荷载流子所观察到的极性相反。将所观察到的TRMC动力学与无机钙钛矿（SrTiO 3和BaTiO 3）的TRMC动力学进行比较，并表征其对温度、频率和近红外秒推脉冲的依赖性，我们得出结论，上述行为是由于极化子空穴的捕获。
Organic–inorganic metal halide perovskites (MHPs) exhibit prominent electronic and optical properties benefiting the performance of solar cells and light-emitting diodes. However, the dielectric properties of these materials have remained poorly understood, despite probably influencing delayed charge recombination and device capacitance. Herein, we characterize the unprecedented dielectric behavior of MHPs comprising methylammonium cations, Pb/Sn as metals, and Br/I as halides using time-resolved microwave conductivity (TRMC) measurements. At specific compositions, the above MHPs exhibit negative real and positive imaginary photoconductivities, the polarities of which are opposite those observed for conventional photogenerated charge carriers. Comparing the observed TRMC kinetics with that of inorganic perovskites (SrTiO3 and BaTiO3) and characterizing its dependence on temperature, frequency, and near-infrared second push pulse, we conclude that the above behavior is due to the trapping of polaronic hole...