Improvement of electrodeposited Sb2Se3 thin film photoelectroactivity by cobalt grain boundary modification

Abstract

This work presents, for the first time, the effects of cobalt-modification on the photoelectrochemical properties of Sb₂Se₃ thin films. The insertion of Co²⁺ ions caused an increase in the photocurrent, without protecting and catalytic layers, of 2.5 times towards the hydrogen evolution reaction compared with an unmodified film in the same period and minimized the initial photocorrosion of the material. However, other properties such as bandgap and crystalline structure were not altered by the low degree of modification used in this work. Different results led us to infer that the Co²⁺ ions modified the grain boundaries (GBs) of the Sb₂Se₃ films, creating a local and specific GB inversion and causing these improvements observed in the photoelectrocatalytic properties of the modified films.