Nanoparticle transformation from ZnO to ZnS through anion exchange with di-tert-butyl disulphide

Abstract

The chemical transformation from zinc oxide (ZnO) to zinc sulphide (ZnS), using di-tert-butyl disulphide (TBDS) as a highly reactive sulphur precursor, is demonstrated herein. Through anion exchange, we investigate the phase and morphological changes associated with the nanoparticle (NP) transformation of ZnO to ZnS using TBDS. The Zn-O-S alloy was not formed through the anion exchange reaction, only the ZnO and ZnS phases were detected. The NPs were transformed from a solid sphere to a hollow structure, induced by the nanoscale Kirkendall effect. Even with the dramatic shape and phase changes occurring in the NPs, the Zn oxidation state remained as 2+ throughout the 2 h anion exchange reaction. In addition, trioctylphosphine (TOP), a soft base ligand, increased the anion exchange reaction rate, facilitating the reaction with TBDS. Furthermore, anion exchange with elemental sulphur required a longer reaction time (3 h) than that with TBDS (2 h). Consequently, this study offers not only insights into phase and morphological transformations by anion exchange, but also the advantages of utilizing TBDS as a sulphur precursor.