Liquid–solid spinodal decomposition mediated synthesis of Sb2Se3 nanowires and their photoelectric behavior

Abstract

The convenient synthesis of one-dimensional nanostructures of chalcogenide compounds with a visible band-gap is an essential research topic in developing next-generation photoelectronic devices. In particular, the design of a theoretically predictable synthesis process provides great flexibility and has a considerable ripple effect in nanotechnology. In this study, a novel rational growth approach is designed using the spinodal decomposition phenomenon for the synthesis of the Sb<inf>2</inf>Se<inf>3</inf> nanowires, which is based on the thermodynamic phase diagram. Using a stacked elemental layer (Sb/Sb-Se/Se) and heat treatment at 623 K for 30 min under an N<inf>2</inf> atmosphere, the vertically inclined one-dimensional nanostructures are experimentally demonstrated. An additional annealing process at 523 K in a vacuum effectively removed excess Se elements due to their high vapor pressure, resulting in highly dense single crystal Sb<inf>2</inf>Se<inf>3</inf> nanowire arrays. Adaption of our synthesis approach enables significantly improved photocurrent generation in the vertically stacked structure (glass/ITO/Sb<inf>2</inf>Se<inf>3</inf> nanowires/ITO/PEN) from 6.4 (dark) to under 690 μA (at 3 V under AM 1.5G). In addition, a photoelectrochemical test demonstrated their p-type conductivity and robust photocorrosion performance in 0.5 M H<inf>2</inf>SO<inf>4</inf>. This journal is © The Royal Society of Chemistry