Flexible and Self‐Powered Photodetector Arrays Based on All‐Inorganic CsPbBr3 Quantum Dots

• Published in: Advanced materials (Weinheim) 2020-06, Vol.32 (22), p.e2000004-n/a
• Main Authors: Shen, Kai, Xu, Hao, Li, Xiao, Guo, Jian, Sathasivam, Sanjayan, Wang, Mingqing, Ren, Aobo, Choy, Kwang Leong, Parkin, Ivan P., Guo, Zhengxiao, Wu, Jiang
• Format: Article
• Language: English
• Subjects: Arrays; Carrier lifetime; Carrier transport; Cesium bromides; Circuits; flexible devices; Materials science; Morphology; Perovskites; photodetector arrays; Photoluminescence; Photometers; Quantum dots; self‐powered devices
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202000004

Flexible devices are garnering substantial interest owing to their potential for wearable and portable applications. Here, flexible and self‐powered photodetector arrays based on all‐inorganic perovskite quantum dots (QDs) are reported. CsBr/KBr‐mediated CsPbBr3 QDs possess improved surface morphology and crystallinity with reduced defect densities, in comparison with the pristine ones. Systematic material characterizations reveal enhanced carrier transport, photoluminescence efficiency, and carrier lifetime of the CsBr/KBr‐mediated CsPbBr3 QDs. Flexible photodetector arrays fabricated with an optimum CsBr/KBr treatment demonstrate a high open‐circuit voltage of 1.3 V, responsivity of 10.1 A W−1, specific detectivity of 9.35 × 1013 Jones, and on/off ratio up to ≈104. Particularly, such performance is achieved under the self‐powered operation mode. Furthermore, outstanding flexibility and electrical stability with negligible degradation after 1600 bending cycles (up to 60°) are demonstrated. More importantly, the flexible detector arrays exhibit uniform photoresponse distribution, which is of much significance for practical imaging systems, and thus promotes the practical deployment of perovskite products. CsBr/KBr‐additive‐assisted all‐inorganic perovskite quantum dots demonstrate reduced nonradiative recombination paths and improved carrier transport. The as‐fabricated self‐powered flexible photodetector arrays exhibit superior photoresponse and electrical stability under different bending conditions (60° and 1600 cycles) with marginal degradation. Moreover, uniform photoresponse is achieved in photodetector arrays, promising for photosensing and imaging systems.