Flexible Self-Powered Weak Light Detectors Based on ZnO/CsPbBr₃/γ-CuI Heterojunctions

Area of Science:

• Materials Science
• Optoelectronics
• Device Physics

Background:

• Halide perovskites (HPs) offer excellent optical and electrical properties for next-generation photodetectors (PDs).
• Long-term stability and robustness remain significant challenges for practical HP-based PD applications.

Purpose of the Study:

• To fabricate flexible, self-powered photodetectors with enhanced stability and performance for weak light detection.
• To investigate the potential of a ZnO/CsPbBr₃/γ-CuI heterojunction structure for robust optoelectronic applications.

Main Methods:

• Fabrication of flexible self-powered PDs using a high vacuum deposition system with a ZnO/CsPbBr₃/γ-CuI structure.
• Characterization of device performance, including detectivity, response speed, environmental stability, and mechanical flexibility.
• Assembly of a 15 × 15 PD array for image sensing applications.

Main Results:

• Achieved high detectivity (8.1 × 10¹³ Jones) and rapid response times (3.9/1.8 μs) in self-powered devices.
• Demonstrated excellent environmental stability and mechanical flexibility, with unchanged photocurrent after 7000 s operation and 100 bending cycles.
• Successfully fabricated a 15 × 15 PD array capable of capturing high-contrast images, showcasing device uniformity and sensitivity.

Conclusions:

• The ZnO/CsPbBr₃/γ-CuI heterojunction is a feasible and practical material system for high-performance, stable, and flexible photodetectors.
• The developed self-powered PDs show significant promise for weak light detection and image formation applications.
• Overcoming stability challenges opens new avenues for halide perovskite-based optoelectronic devices.