Han Changfeng, Wei Zhengxuan, Wang Kai, Yu Haomiao, Deng Liangliang, Zhu Xixiang, Yang Hanjun, Sun Xiaojuan, Zhao Fenggui, Zhang Qi, Yang Qin, Hu Bin
Opt Express. 2018 Oct 1;26(20):26307-26316. doi: 10.1364/OE.26.026307.
Methylammonium lead iodide (CHNHPbI), with the organic-inorganic hybrid perovskite (OIHP) structure, has gained tremendous research interest due to its excellent photo-electron conversion ability in the application of photovoltaics. Despite its solution processed polycrystalline thin film form in solar cells, the single crystalline counterpart may offer some incredibly novel optoelectronic functionalities. In this work, a sizable (>5 mm) and high quality CHNHPbI single crystal has been synthesized by the inverse temperature crystallization method, and a white-light photodetector of the structure glass/ITO/Ga/ CHNHPbI/Au was fabricated. Overbroad photo-excitation intensities ranging from 0.1 mW/cm to 100 mW/cm using a sun-light simulator, the on-off ratio is tunable in a wide-range from 65 to 2250 at zero bias voltage. The responsivity (R) and detectivity (D*) are 36.2 mA/W and 2.68×10 Jones respectively at a weak white-light intensity such as 0.1 mW/cm. Both the photodetective parameters decrease with the increase of the illumination intensity. Based on impedance spectra obtained at working condition and light intensity dependent J measurements, the surface trap-assist recombination may play a dominating role. The corresponding lifetime (τ) and resistance (R) exhibit fast decays at higher illumination intensities. This fundamental study may pave the way for exploring the contribution of the surface trap-assist recombination in the CHNHPbI single crystal based photodetector. We believe it is applicable for integration in micro-photonics for sensitive and weak white-light photo-detection.
碘化甲铵铅（CH₃NH₃PbI₃）具有有机-无机杂化钙钛矿（OIHP）结构，因其在光伏应用中出色的光电子转换能力而受到了极大的研究关注。尽管其在太阳能电池中以溶液处理的多晶薄膜形式存在，但单晶形式可能会提供一些令人难以置信的新颖光电功能。在这项工作中，通过逆温结晶法合成了尺寸较大（>5毫米）且高质量的CH₃NH₃PbI₃单晶，并制备了结构为玻璃/ITO/Ga/CH₃NH₃PbI₃/Au的白光光电探测器。使用太阳光模拟器，在0.1 mW/cm²至100 mW/cm²的宽光激发强度范围内，零偏压下的开/关比可在65至2250的宽范围内调节。在0.1 mW/cm²这样的弱白光强度下，响应度（R）和探测率（D*）分别为36.2 mA/W和2.68×10¹² Jones。随着光照强度的增加，两个光电探测参数均降低。基于工作条件下获得的阻抗谱以及与光强相关的J测量结果，表面陷阱辅助复合可能起主导作用。在较高光照强度下，相应的寿命（τ）和电阻（R）呈现快速衰减。这项基础研究可能为探索表面陷阱辅助复合在基于CH₃NH₃PbI₃单晶的光电探测器中的作用铺平道路。我们相信它适用于集成到微光子学中以进行灵敏和微弱白光光探测。
