Preparation of a flexible photoanode of the photoelectrochemical ultraviolet photodetector based on rutile TiO2 nanowires and the suppressed charge recombination at solid/liquid interface

Abstract Flexible ultraviolet (UV) photodetector exhibits a promising application in portable electronic gadgets, display devices and biomedical imaging. In this study, a flexible photoanode of the photoelectrochemical (PEC)-type UV photodetector based on rutile TiO 2 nanowires (TiO 2 NWs) grown on carbon fiber cloth is realized. In photovoltaic applications, an insulating layer is usually introduced to suppress interfacial recombination and reduce the surface trap states. The interfacial recombination of semiconductor/electrolyte is suppressed by coating an Al 2 O 3 barrier layer on the TiO 2 NWs. The photodetectors of the TiO 2 @Al 2 O 3 NWs show stable photocurrent, a high light/dark current ratio ( I light / I dark ) of 1170, a faster rise and decay response times of 0.09 and 0.09 s, and excellent spectral selectivity from 300 to 400 nm. The peak responsivity of the photodetectors reaches 2.8 mA W −1 at 360 nm. This flexible photoanode have a potential application in wearable PEC UV photodetector.