A flexible UV photodetector based on ZnO/SiO ₂ /PEDOTPSS pin-junction with enhanced wide UV detection capability

The development of flexible UV photodetectors (PDs) has always been a research hotspot in the field of optoelectronics. However, achieving wide UV spectral coverage while maintaining high responsivity and stability remains a challenge. We propose a novel device structure that integrates an SiO 2 film as an intrinsic layer into a ZnO/PEDOT:PSS p-n heterojunction to construct a p-i-n heterojunction flexible PD. This PD is based on flexible polyethylene terephthalate (PET) and is fabricated using magnetron sputtering and spin-coating processes by sequentially depositing each functional film. At a 20 V bias, the peak responsivity of ZnO/SiO 2 /PEDOT:PSS PD at 365 nm is 390 times that of pure ZnO PD. The rise time and decay time corresponding to the response speed are 0.072 s and 0.080 s, respectively. The research results indicate that the spectral response range of the p-i-n PD has been significantly broadened, successfully covering the 250 - 400 nm range, achieving detection from UVC to UVA. The p-i-n heterojunction can effectively broaden the depletion layer and optimize the electric field distribution, thereby achieving wide-spectrum detection and performance enhancement simultaneously. This provides a simple and effective strategy for the development of high-performance, broadband, flexible UV PDs.