Fabrication and enhanced photoelectric properties of a novel Bi9O7.5S6/CdS composite film

Abstract

Layered bismuth oxychalcogenides have been demonstrated as potential candidates for high-speed and low-power electronics due to their outstanding environmental stability and high carrier mobility, but the photoelectric performance of bulk species is still far from satisfactory. Herein, a novel Bi₉O_7.5S₆/CdS composite film with a type-II heterojunction has been successfully prepared by combining chemical bath deposition (CBD) and spin-coating technologies. The structure, morphology, optical and photoelectric properties of the samples were investigated systematically. The photoelectric current of the Bi₉O_7.5S₆/CdS composite film was obtained as 32.49 μA cm⁻² at 1 V, which is about 13.9-fold and 3.3-fold higher than those of bare Bi₉O_7.5S₆ and CdS. An enhanced photoelectric response and photostability were achieved in the Bi₉O_7.5S₆/CdS composite film, and can be appropriately attributed to the improved separation and transfer of photogenerated carriers driven by the type-II heterojunction. This work offers a promising route to develop high-performance visible-light photoelectric devices with type-II heterojunctions.