Oleic acid-induced, controllable surface oxidation to enhance the photoresponse performance of Sb2Se3 nanorods

Abstract

Surface oxidation frequently occurs in non-oxide antimony chalcogenides, which is a double-edged sword for their (opto)electronic properties and applications. Here we report that the photoelectronic performance of Sb₂Se₃ nanorods (NRs) can be improved through an appropriate degree of surface oxidation. During the synthesis, the volume ratio of oleic acid (OA)/oleylamine (OLA) was varied to control the oxidation degrees of the Sb₂Se₃ NRs, which span 1.20–51.49% with increasing OA ratio as revealed by X-ray photoelectron spectroscopy (XPS) analysis. A medium level of surface oxidation, typically 20–30% found here, is beneficial to the enhancement of the photocurrent, on/off ratios and photostability of the Sb₂Se₃ NRs when evaluated in a sandwich-type ITO/Sb₂Se₃/ITO photoconductor device. Surface hydroxylation, which is boosted by the presence of Sb–oleate and trace H₂O remaining in the reaction system, is suggested to facilitate the formation of Sb–OH bonds and the OA-volume dependent oxidation at the surface of Sb₂Se₃.