Dramatic Responsivity Enhancement Through Concentrated H<sub>2</sub>SO<sub>4</sub> Treatment on PEDOT:PSS/TiO<sub>2</sub> Heterojunction Fibrous Photodetectors
Xiaolei Deng, Ziliang Li, Hui Liu, Zhefei Zhao, Lingxia Zheng, Xiaowei Shi, Liang Wang, Xiaosheng Fang, Huajun Zheng
Abstract
Abstract In order to satisfy the growing requirements of wearable electronic devices, 1D fiber‐shaped devices with outstanding sensitivity, flexibility, and stability are urgently needed. In this study, a novel inorganic‐organic heterojunction fibrous photodetector (FPD) based on poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and highly ordered TiO 2 nanotube array is fabricated, which endows a high responsivity, large external quantum efficiency, and fast response speed at 3 V bias. To further ameliorate its performance in the self‐powered mode, a facile acid treatment is adopted and the assembled H‐PEDOT:PSS/TiO 2 FPD demonstrates outstanding self‐powered properties with ≈3000% responsivity enhancement (161 mA W −1 at 0 V under 365 nm irradiation, photocurrent enhancement of ≈50 times) compared with the untreated device. It is found that the concentrated H 2 SO 4 post‐treatment helps decrease the tube wall thickness of TiO 2 and partially removes the insulated PSS component in PEDOT:PSS, leading to enhanced conductivity and facilitated charge transportation, and thereby superb responsivity/photocurrent enhancement of self‐powered H‐PEDOT:PSS/TiO 2 FPD. This low‐cost and high‐performance self‐powered FPD shows high potential for applications in wearable electronic devices.