Sulfur‐Supplemented Vapor Transport Deposition of Sb<sub>2</sub>S<sub>3</sub> and Sb<sub>2</sub>(S,Se)<sub>3</sub> for High‐Performance Hydrogen Evolution Photocathodes
Weitao Qiu, Renbo Lei, Xing Tang, Yupu Tang, Xianzhen Huang, Kai Zhang, Ziqiong Lin, Shuang Xiao, Xinwei Wang, Shihe Yang
Abstract
Chalcogen vacancy has long been recognized as a detrimental deep‐level defect that can induce severe charge recombination and diminish the quasi‐Fermi‐level splitting in Sb 2 S 3 and Sb 2 Se 3 , especially when they are prepared by physical vapor deposition in vacuum. In order to counter this limitation, a sulfur‐supplemented vapor transport deposition technique is proposed, which intentionally introduces low pressure sulfur vapor and can thus afford low‐defect‐density antimony chalcogenide films. The resultant photocathodes modified with conformal TiO 2 protection layer and Pt cocatalyst demonstrate a photocurrent as high as 20 mA cm −2 along with a much improved fill factor and onset potential, achieving an applied bias photoconversion efficiency above 1%. This work highlights the importance of the vacancy defect passivation and the preferential crystalline orientation in the film in promoting the photocathode performance.