Complex Transfer Reaction from ZnO to ZnS Quantum Dots Driven by Surface Anions

Abstract

This work demonstrates preferential transfer of 8-hydroxyquinoline-5-sulfonic acid (HQS) from surface of ZnO quantum dots to ZnS quantum dots in the form of Zn(QS)2 complex. This is an instance of inter quantum dot complex or Z-type ligand transfer that depends on solvent system—more precisely, solubility of the migrating complex. The migration can be explained using Langmuir model by considering two parallel adsorption equilibria on ZnO and ZnS surfaces. We also propose that higher stability of the zinc quinolato complex on ZnS surface in comparison to that of ZnO is the driving force of the reaction.