Abstract
The photoelectrochemical properties of (Ag,Cu)GaSe(2) (ACGSe) modified by deposition of CdS and CuGa(3)Se(5) layers were investigated. The CdS and CuGa(3)Se(5) layers formed p-n junctions with an appropriate band diagram on the surface of the electrode and they clearly increased the cathodic photocurrent and onset potential. The Pt, CdS, and CuGa(3)Se(5) modified ACGSe (Pt/CdS/CuGa(3)Se(5)/ACGSe) with an appropriate thickness of CuGa(3)Se(5) layers (ca. 100 nm) showed a cathodic photocurrent of 8.79 mA cm(-2) at 0 V(RHE) and an onset potential of 0.62 V(RHE) (defined as cathodic photocurrent of 1.0 mA cm(-2)) under simulated sunlight irradiation in 0.1 M Na(2)HPO(4) (pH 10). Pt/CdS/CuGa(3)Se(5)/ACGSe showed durable cathodic current under the observed reaction conditions and hydrogen was evolved for about 20 days.