Enhanced photoelectric performance in a CdO/ZnO/Ag heterostructure thin film photoanode

Abstract

Abstract Hydrogen generation via solar water splitting using a semiconductor photo-electrode has been extensively explored owing to its contribution to the development of renewable energy. Although pure ZnO has many advantages, its wide band-gap limits its use in solar photoelectric applications. Recently, significant advancements have been made in the photoelectrochemical applications due to the development of multi-component heterostructures. In this study, CdO/ZnO/Ag heterostructure films are fabricated via pulsed laser deposition, and their structure, morphology, and photoelectric properties are intensively investigated. The results indicate that the CdO/ZnO/Ag heterostructure thin film exhibits a wide absorption range from ultraviolet to visible light and an enhanced absorption intensity. The photocurrent density of the heterostructure film reaches 0.25 μA/cm2, which is 4.2 times higher than that of pure ZnO film under visible light irradiation. The increased visible light photocurrent response is mainly attributed to the localized surface plasmon effect of Ag nanoparticles. The band structure of CdO/ZnO promotes the transfer of electrons to CdO, which decreases the recombination of electron-hole pairs at the CdO/ZnO interface and increases the photocurrent. A possible mechanism is proposed here to interpret the enhancement of the photoelectric response.