Flexible self-powered γ-CuI/AZO p-n heterojunction UV photodetector with fatigue-tolerant operation

A flexible γ-CuI/AZO p-n heterojunction UV photodetector was successfully fabricated on a PEN substrate. • Self-powered UV detection with R of 4 mA/W, D* of 2.62 × 10 11 Jones, and fast rise time and decay time (306/116 ms). • The heterojunction exhibits excellent mechanical durability, maintaining stable photoresponse after 500 bending cycles. Flexible ultraviolet (UV) photodetectors have broad application prospects in wearable electronics and low-power optoelectronic systems. In this work, a self-powered UV photodetector based on a γ-CuI/AZO p-n heterojunction was successfully fabricated on a flexible polyethylene naphthalate substrate. Both γ-CuI and AZO films exhibit high visible-light transmittance with optical bandgaps of 3.03 eV and 3.28 eV, respectively, rendering them suitable for UV detection. The device demonstrates distinct rectification behavior in the dark and a markedly enhanced photoresponse under 365 nm UV illumination, achieving stable self-powered operation at 0 V bias. Under a 0 V bias and an incident power density of 103.2 mW/cm 2 , the device demonstrates rise and decay times of 306 ms and 116 ms, respectively. At 33.4 mW/cm 2 , the device achieves a responsivity of 4 mA/W and a specific detectivity of 2.62 × 10 11 Jones, confirming its effective self-powered UV detection capability. Furthermore, cyclic bending tests under a fixed 5-mm radius curvature revealed that the device maintains distinguishable photoresponse after 500 bending cycles, demonstrating robust mechanical tolerance and reliable photodetection under fatigue deformation. This work provides a feasible route for the construction of flexible self-powered UV photodetectors based on p–n heterojunctions. Download: Download high-res image (157KB) Download: Download full-size image