A high performance ZnO based photoelectrochemical cell type UV photodetector with [Co(bpy)3]3+/2+ electrolyte and PEDOT/ITO counter electrode

Abstract

We fabricated a high performance self-powered photoelectrochemical cell (PECC) type UV photodetector with ZnO nanorod arrays (NRs) as the photoanode, [Co(bpy)₃]^3+/2+ as the electrolyte and ITO glass coated by polymer poly(3,4-ethylenedioxythiophene) (PEDOT), PEDOT/ITO, as the counter electrode (CE). The UV photodetector shows a good photovoltaic performance (V_OC = 0.5 V, I_SC = 6.2 μA) and a high photosensitivity of 263 under the illumination of 365 nm UV light with an intensity of 2 mW cm⁻². The device also shows a high response speed (response time < 0.2 s). The high photosensitivity and rapid response speed are attributed to the good electrocatalytic activity of PEDOT towards Co-complex redox shuttle. The high performance of the detector, together with the Pt-free low cost CE and the facile fabricating method, makes the device promising in optoelectronic applications.