Tang Yingjie, Jin Peng, Wang Yan, Li Dingwei, Chen Yitong, Ran Peng, Fan Wei, Liang Kun, Ren Huihui, Xu Xuehui, Wang Rui, Yang Yang Michael, Zhu Bowen
College of Information Science and Electronic Engineering, Zhejiang University, 310027, Hangzhou, China.
Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, 310024, Hangzhou, China.
Nat Commun. 2023 Aug 16;14(1):4961. doi: 10.1038/s41467-023-40711-1.
Metal halide perovskites are promising for next-generation flexible photodetectors owing to their low-temperature solution processability, mechanical flexibility, and excellent photoelectric properties. However, the defects and notorious ion migration in polycrystalline metal halide perovskites often lead to high and unstable dark current, thus deteriorating their detection limit and long-term operations. Here, we propose an electrical field modulation strategy to significantly reduce the dark current of metal halide perovskites-based flexible photodetector more than 1000 times (from 5 nA to ~5 pA). Meanwhile, ion migration in metal halide perovskites is effectively suppressed, and the metal halide perovskites-based flexible photodetector shows a long-term continuous operational stability (8000 s) with low signal drift (4.2 × 10 pA per second) and ultralow dark current drift (1.3 × 10 pA per second). Benefitting from the electrical modulation strategy, a high signal-to-noise ratio wearable photoplethysmography sensor and an active-matrix photodetector array for weak light imaging are successfully demonstrated. This work offers a universal strategy to improve the performance of metal halide perovskites for wearable flexible photodetector and image sensor applications.
金属卤化物钙钛矿因其低温溶液可加工性、机械柔韧性和优异的光电性能，在下一代柔性光电探测器方面具有广阔前景。然而，多晶金属卤化物钙钛矿中的缺陷和众所周知的离子迁移常常导致高且不稳定的暗电流，从而降低其检测极限和长期运行性能。在此，我们提出一种电场调制策略，可将基于金属卤化物钙钛矿的柔性光电探测器的暗电流显著降低1000倍以上（从约5 nA降至约5 pA）。同时，金属卤化物钙钛矿中的离子迁移得到有效抑制，基于金属卤化物钙钛矿的柔性光电探测器表现出长期连续运行稳定性（约8000 s），信号漂移低（约每秒4.2×10 pA），暗电流漂移超低（约每秒1.3×10 pA）。受益于这种电调制策略，成功展示了一种高信噪比可穿戴光电容积脉搏波传感器和用于弱光成像的有源矩阵光电探测器阵列。这项工作为改善金属卤化物钙钛矿在可穿戴柔性光电探测器和图像传感器应用中的性能提供了一种通用策略。
