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

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.