Remarkable charge transfer between CdSe seeded CdS nanorods and its metallic and semiconducting tips and its effect on Rhodamine B photodegradation

Abstract

Hybrid colloids (HCs) have shown distinct optical, electric, and optoelectronic properties from the components, mainly because of electronic interplay between the components. Here we investigate different charge transfer behaviors of dumbbell-structured CdSe-seeded CdS nanorods with metallic and semiconducting tip materials respectively studied by UV-vis and photoluminescence (PL) spectra, i.e. gold-tipped CdSe-seeded CdS nanorods and palladium sulfide-tipped CdSe-seeded CdS nanorods. They have shown remarkably different optical properties due to different charge transfer processes, i.e. one is only excited electrons transferred from the CdS shell to gold tips while the other is holes as well as electrons injected from the CdS shell into the palladium sulfide tips. The effect of the charge transfer on Rhodamine B (RhB) photodegradation is further investigated. Very interestingly, totally opposite effects were found, that is gold tips enhanced photodegradation rate while palladium sulfide tips vastly reduced photodegradation. Those phenomena are well explained by our proposed mechanism for the charge transfer. This study enables better design of HCs for improved photocatalysis and better photovoltaics.