论文标题：Ultrafast zero-bias photocurrent and terahertz emission in hybrid perovskites

期刊：Communications Physics

作者：Petr A. Obraztsov, Dmitry Lyashenko, Pavel A. Chizhov, Kuniaki Konishi, Natsuki Nemoto, Makoto Kuwata-Gonokami, Eric Welch, Alexander N. Obraztsov & Alex Zakhidov

发表时间：2018/04/19

数字识别码：10.1038/s42005-018-0013-8

原文链接：https://www.nature.com/articles/s42005-018-0013-8?utm_source=Other_website&utm_medium=Website_links&utm_content=RenLi-Nature-Communications_Physics-Materials_Physics-China&utm_campaign=NEWCOMMS_USG_rlp8212_perovskite_sciencenet_article_June_4th

本周《通讯-物理学》发表的一项研究Ultrafast zero-bias photocurrent and terahertz emission in hybrid perovskites展示了在室温条件下，甲基碘化铅胺中超快光电流的产生以及自由空间太赫兹的发射。

甲基碘化铅胺是一种标准的可用于低成本印刷太阳能电池的杂化有机钙钛矿材料，其功率转化效率高于20%。然而，目前关于在杂化钙钛矿中的光与物质相互作用的本质，以及潜藏在器件操作过程中的确切物理机制仍存有争论。

来自俄罗斯普罗霍罗夫物理研究所和东芬兰大学的Petr A. Obraztsov，美国德克萨斯州立大学的Dmitry Lyashenko和日本东京大学的Kuniaki Konishi及其同事，他们报道了由飞秒光脉冲在无偏压的杂化钙钛矿中诱导的室温超快光电流的产生，以及自由空间太赫兹的发射。他们观察到的光响应的极化依赖与注入和转移电流相结合所产生的体光伏效应一致。对这种类型光电流的观测可以揭示出由CH3NH3PbI3的间接带隙所引起的较低的重组和较长的载流子扩散长度。自然的弹道移位和注入的光电流可以使第三代钙钛矿太阳能电池的效率超过肖克利——奎伊瑟效率极限。通过光偏振对光电流的控制也可为钙钛矿自旋电子学和可控太赫兹器件开辟新的途径。

摘要：Methylammonium lead iodide is a benchmark hybrid organic perovskite material used for low-cost printed solar cells with a power conversion efficiency of over 20%. Nevertheless, the nature of light–matter interaction in hybrid perovskites and the exact physical mechanism underlying device operation are currently debated. Here, we report room temperature, ultrafast photocurrent generation, and free-space terahertz emission from unbiased hybrid perovskites induced by femtosecond light pulses. The polarization dependence of the observed photoresponse is consistent with the bulk photovoltaic effect caused by a combination of injection and shift currents. Observation of this type of photocurrents sheds light on the low recombination and long carrier diffusion lengths arising from the indirect bandgap in CH3NH3PbI3. Naturally ballistic shift and injection photocurrents may enable third-generation perovskite solar cells with efficiency exceeding the Shockley–Queisser limit. The demonstrated control over photocurrents with light polarization also opens new venues toward perovskite spintronics and tunable THz devices.

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期刊介绍：Communications Physics is an open access journal from Nature Research publishing high-quality research, reviews and commentary in all areas of physics. Research papers published by the journal represent significant advances bringing new insight to a specialized area of research.

Communications Physics complements the other Nature Research journals by providing a new open access option for physicists while applying less stringent criteria for impact and significance than the Nature-branded journals, including Nature Communications. All Nature Research journals, including Communications Physics, apply the same criteria for technical validity and adherence to ethical standards.（来源：科学网）