Liang Wen-Qing, Li Ying, Ma Jing-Li, Wang Yue, Yan Jing-Jing, Chen Xu, Wu Di, Tian Yong-Tao, Li Xin-Jian, Shi Zhi-Feng
Key Laboratory of Materials Physics of Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Daxue Road 75, Zhengzhou 450052, China.
Nanoscale. 2020 Sep 7;12(33):17213-17221. doi: 10.1039/d0nr03630g. Epub 2020 Aug 17.
Recently, the newly emerging lead-halide perovskites have received tremendous attention in the photodetection field because of their intrinsic large light absorption and high well-balanced carrier transport characteristics. Unfortunately, the issue of instability and the existence of toxic lead cations have greatly restricted their practical applications and future commercialization. Furthermore, the previous studies on perovskite photodetectors mainly operate in visible and near-infrared light region, and there are practically no relevant reports aimed at the deep-ultraviolet (DUV) region. In this study, an air-stable and DUV-sensitive photoconductive detector was demonstrated with a solution-processed ternary copper halides CsCuI thin films as the light absorber. The proposed photodetector is very sensitive to wavelengths of light below 320 nm and unresponsive to the visible light. Because of the high material integrity and large surface coverage of the CsCuI thin films, the detector presents an outstanding photodetection performance with a photoresponsivity of ∼17.8 A W, specific detectivity of 1.12 × 10 Jones, and fast response speed of 465/897 μs, superior to previously reported DUV photodetectors based on other material systems. Unlike traditional lead-halide perovskites, the lead-free CsCuI shows remarkable stability against heat, UV light, and environmental oxygen/moisture. Thus, the unsealed photodetector demonstrates good operation stability for 11 h of continuous running in open air. Even after 80-day storage in ambient air, its photodetection capability can nearly be maintained. The results suggest that non-toxic CsCuI could be a potential candidate for stable and environment friendly DUV detectors, enabling an assembly of optoelectronic systems in the future.
最近，新出现的卤化铅钙钛矿因其固有的大光吸收和高度平衡的载流子传输特性，在光电探测领域受到了极大关注。不幸的是，不稳定性问题以及有毒铅阳离子的存在极大地限制了它们的实际应用和未来商业化。此外，先前关于钙钛矿光电探测器的研究主要在可见光和近红外光区域工作，几乎没有针对深紫外（DUV）区域的相关报道。在本研究中，展示了一种空气稳定且对DUV敏感的光电导探测器，其采用溶液处理的三元卤化铜铯（CsCuI）薄膜作为光吸收体。所提出的光电探测器对波长低于320 nm的光非常敏感，对可见光无响应。由于CsCuI薄膜具有高材料完整性和大表面覆盖率，该探测器呈现出出色的光电探测性能，光响应度约为17.8 A/W，比探测率为1.12×10 Jones，响应速度快至465/897 μs，优于先前报道的基于其他材料系统的DUV光电探测器。与传统的卤化铅钙钛矿不同，无铅的CsCuI对热、紫外光以及环境中的氧气/湿气表现出显著的稳定性。因此，未密封的光电探测器在露天连续运行11小时显示出良好的运行稳定性。即使在环境空气中储存80天后，其光电探测能力仍能几乎保持不变。结果表明，无毒的CsCuI可能是稳定且环境友好的DUV探测器的潜在候选材料，有望在未来实现光电系统的组装。
