Constructing Caesium Based Lead-Free Perovskite Photodetector Enabling Self-Powered Operation with Extended Spectral Response.
Constructing Caesium Based Lead-Free Perovskite Photodetector Enabling Self-Powered Operation with Extended Spectral Response.
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DOI：
10.1021/acsami.0c14083
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发表时间：
2020-09
影响因子：
9.5
通讯作者：
A. Hussain
中科院分区：
文献类型：
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作者：
A. Hussain
自从发现最先进的杂化卤化物钙钛矿以来，其在光电系统中的应用引起了广泛的关注。然而，铅（Pb）的毒性和有机成分引起的挥发性阻碍了其未来的大规模市场发展。在此，合成了一种基于坚固 Cs3Bi2I9 的全无机无铅卤化物钙钛矿，并实现了其在光电探测器应用中的潜力。材料特性研究表明其具有良好的晶体质量和强吸收系数，适合光电检测。获得了基于扩展吸收的一个有趣的特征，即弱声子辅助跃迁的特征。此外，形态特征显示了 Cs3Bi2I9 美丽生长的微米级晶体。制造的光电探测器展示了自供电操作（零偏置状态），暗电流非常低，为 0.46 pA。得益于此，实现了 1.4 × 104 的改进光敏度。此外，除了自供电光电探测外，光电探测器还表现出宽光谱响应（450 - 950 nm）、高探测率（1.2 × 1010/1.6 × 1012 Jones）、高响应率（0.59 µAW-1/3.8 mAW-1）和在0.1 mWcm-2弱光信号下的快速响应速度（ms）和0.25 cm2的较大有效面积。该光电探测器表现出高光稳定性，在近 2000 次重复循环后仍能保持良好状态而不会退化。更引人注目的是，基于钙钛矿薄膜的核心稳定性，即使暴露在潮湿空气（75％RH）后，光电探测器也能实现三个月（90天）的优异长期稳定性。因此，这项研究强调了为数不多的无铅全无机钙钛矿光电探测器之一，它采用简单的器件架构，具有更大的有源面积，在低光条件下的自供电模式下表现出高效且可比的性能，从而脱颖而出。
Since the discovery of the state-of-the-art hybrid halide perovskites, its application in optoelectronic systems has drawn considerable attention. However, the toxicity from lead (Pb) and the volatility induced by organic constituents hinder its future large-scale market development. Herein, a fully inorganic Pb-free halide perovskite based on robust Cs3Bi2I9 is synthesized and realized its potential in photodetector application. The material property investigation suggests the good crystalline quality with strong absorption coefficient suitable for photodetection. An interesting feature based on the extended absorption is obtained which is the characteristics of a weak phonon-assisted transition. Additionally, the morphological features display the beautifully grown micron-sized crystals of Cs3Bi2I9. The fabricated photodetector demonstrated the self-powered operation (zero-bias state) with a very low dark current of 0.46 pA. Profiting from this, improved photosensitivity of 1.4 × 104 is achieved. Moreover, along with self-powered photodetection, the photodetector exhibit broad spectral response (450 - 950 nm), high detectivity (1.2 × 1010/1.6 × 1012 Jones), high responsivity (0.59 µAW-1/3.8 mAW-1) and fast response speed (ms) under a weak optical signal of 0.1 mWcm-2 with a larger active area of 0.25 cm2. The photodetector show high photo-stability which well retained for almost 2000 repetitive cycles without degradation. More strikingly, based on the core-stability of the perovskite film, an excellent long-term stability of three months (90 days) is achieved for the photodetector even after exposure to moist air (75% RH). This study thus highlights one of the few Pb-free all-inorganic perovskite photodetectors employing a simple device architecture with a larger active area that outshines by showing efficient and comparable performance under self-powered mode with low light conditions.