Pyro-phototronic effect enhanced the performance of TiO2 NRs/BiOCl//PEDOS heterojunction for a UV photodetector

This study presents the construction of an organic–inorganic heterojunction ultraviolet (UV) photodetector (PD) through face-to-face assembly. The synergistic effects of bismuth oxychloride (BiOCl) and titanium dioxide nanorods (TiO2 NRs) improve carrier transport efficiency and enhance the performance of the UV photodetector. The combination of BiOCl with TiO2 NRs generates a pyro-phototronic effect and increases the surface oxygen vacancies of TiO2 NRs, resulting in enhanced carrier transport efficiency, increased transient photocurrent, and reduced dark current in TiO2-based UV photodetectors. The enhanced photosensitivity of chloride (Cl) ions bound to selenium (Se) ions promotes easy electron injection from poly (3,4-ethylene dioxyselenophene) (PEDOS) into BiOCl, leading to accelerated electron transfer and a shortened response time. Compared to TiO2 NRs/BiOCl//TiO2 NRs/BiOCl, the TiO2 NRs/BiOCl//PEDOS heterojunction exhibits a fast photoresponse with a rise time of 0.0802 s and a fall time of 79.8 ms. The responsivity is significantly improved from 11.0 mA/W to 108.8 mA/W (a 10-fold enhancement), and the detectivity is increased from 0.67 × 1011 Jones to 1.25 × 1011 Jones at 365 nanomaterials (0 V). These findings provide valuable insights into the mechanism by which BiOCl nanosheets enhance the photodetection performance of devices, contributing to the advancement of UV photodetector technology.