Large-Scale, Uniform-Patterned CsCu₂I₃ Films for Flexible Solar-Blind Photodetectors Array with Ultraweak Light Sensing

Cesium copper halide perovskite is one of the promising materials for solar-blind light detection. However, most of the cesium copper halide perovskite-based photodetectors (PDs) are focused on ultraviolet A detection and realized on the rigid substrate in the single device configuration. Here, a flexible solar-blind PDs array (10 × 10 pixels) based on the CsCu₂I₃ film patterns for ultraweak light sensing and light distribution imaging is reported. Large-scale CsCu₂I₃ film arrays are synthesized with various shapes and uniform dimensions through a simple vacuum-heating-assisted solution method. Benefiting from excellent air stability and superior resistance to the photodegrading of the CsCu₂I₃ film, the array device exhibits long-term stable photoswitching behavior for 8 h and ultralow light detection capability to resolve the light intensity of 6.1 nW cm⁻² with a high responsivity of 62 A W⁻¹, and the array device can acquire clear images of “G”, “X”, and “U” showing the input light distribution. Moreover, the flame detection and warning system based on a curved solar-blind PDs array is demonstrated, which can be used for multi-flame monitoring and locating. These results can encourage potential applications of the CsCu₂I₃ film-based PDs array in the field of optical communication and environment monitoring.