Low-Cost, Flexible, and Wearable UV Photodetector Based on a Spray-Pyrolyzed ZnO Thin Film on Polyester Fabric

This work introduces the fabrication of a flexible UV photodetector based on a ZnO thin film directly deposited onto a woven polyester fabric substrate, marking a significant advancement in wearable optoelectronic device engineering. The integration of semiconducting functionality with a textile platform offers a promising route toward seamless, high-performance, wearable sensors. X-ray diffraction confirms the formation of a phase-pure polycrystalline ZnO layer exhibiting a wurtzite structure with an average crystallite size of ∼33 nm. Advanced morphological and elemental analyses using scanning electron microscopy verify a uniform and conformal ZnO coating across the fibrous textile surface. Critically, the device exhibits outstanding photodetection metrics under low-intensity UV illumination, achieving a high responsivity of 10.2 A/W, a detectivity of 6.86 × 10 13 Jones, and an exceptional external quantum efficiency of 5010%, alongside a peak photocurrent of ∼13 μA at 30 V under 100 μW/cm 2 UV light. A fast photoresponse (∼2 ms) is enabled by efficient carrier separation at the engineered ZnO–carbon interface. This indicates the remarkable mechanical robustness and operational stability of the device under real-world deformations. The photodetector maintains a consistent photoresponse with less than 1.8% variation under repeated bending of up to 60°, demonstrating excellent durability and flexibility. This performance is attributed to the synergistic influence of the piezoelectric effect and dynamic surface oxygen interactions unique to ZnO nanostructures on flexible textiles. This study pioneers a fabric-integrated photodetection platform that combines high sensitivity, speed, and mechanical resilience, positioning ZnO-coated textiles as a groundbreaking solution for next-generation wearable UV-sensing technologies.