Ligand Exchange of Colloidal CdSe Nanocrystals with Stibanates Derived from Sb₂S₃ Dissolved in a Thiol-Amine Mixture

Abstract

Molecular stibanates derived from the dissolution of bulk Sb2S3 in a binary ethylenediamine and mercaptoethanol solvent mixture have been studied as capping ligands for colloidal CdSe nanocrystals. A phase transfer ligand exchange strategy was utilized to effectively install the stibanate ligands onto the CdSe nanocrystals to form stable colloidal suspensions in polar solvents, such as formamide. This methodology was very effective in the removal of insulating native ligands on the as-prepared nanocrystals, with the resulting stibanate-capped CdSe nanocrystals giving low organic content thin films upon spin coating with improved interparticle coupling after heating to temperatures <300 °C. Photoelectrochemical measurements on stibinate-capped CdSe nanocrystal films showed that this novel ligand leads to a > 25-fold increase in photocurrent response relative to as-prepared CdSe nanocrystal films.