Stable, high-sensitivity and fast-response photodetectors based on lead-free Cs2AgBiBr6 double perovskite films

• Main Authors: Yang, Jie, Bao, Chunxiong, Ning, Weihua, Wu, Bo, Ji, Fuxiang, Yan, Zhibo, Tao, Youtian, Liu, Jun-Ming, Sum, Tze Chien, Bai, Sai, Wang, Jianpu, Huang, Wei, Zhang, Wenjing, Gao, Feng
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2020
• Subjects: Science::Physics; Cs2AgBiBr6; Environmental Stability
• Online Access: https://hdl.handle.net/10356/139200; https://doi.org/10.21979/N9/QITZEA
• Institution: Nanyang Technological University

Solution-processed metal halide perovskites (MHPs) have demonstrated great advances on achieving high-performance photodetectors. However, the intrinsic material instability and the toxicity of lead still hinder the practical applications of MHPs-based photodetectors. In this work, the first highly sensitive and fast-response lead-free perovskite photodetectors based on Cs2AgBiBr6 double perovskite films are demonstrated. A convenient solution method is developed to deposit high-quality Cs2AgBiBr6 film with large grain sizes, low trap densities, and long charge carrier lifetimes. Incorporated within a photodiode device architecture comprised of optimized hole- and electron-transporting layers, lead-free perovskite photodetectors are achieved exhibiting a high detectivity of 3.29 × 1012 Jones, a large linear dynamic range of 193 dB, and a fast response time of ≈17 ns. All the key figures of merit of the devices are comparable with the reported best-performing photodetectors based on lead halide perovskites. In addition, the resulting devices exhibit excellent thermal and environmental stability. The nonencapsulated devices show negligible degradation after thermal stressing at 150 °C and less than 5% degradation in the photoresponsivity after storage in ambient air for ≈2300 h. The results demonstrate the great potential of the lead-free Cs2AgBiBr6 double perovskite in applications for environmentally friendly and high-performance photodetectors.