Long-Lived Emission in Type-II CdS/ZnSe Core/Crown Nanoplatelet Heterostructures

Abstract

The synthesis of core/crown heterostructures allows us to modify the properties of nanoplatelets (NPLs) by altering the lateral dimensions without affecting their thickness, that is, the confinement direction. We have presented the synthesis and study of photophysical properties of type-II CdS/ZnSe core/crown NPLs, where electron-wave function is confined to CdS core, while hole wave function resides in ZnSe crown. The recombination of the photogenerated excitons in CdS and ZnSe occurs across the interface of both semiconductors and due to which the emission shows a red shift of ∼100 nm. The lifetime of CdS/ZnSe increases almost two orders of magnitude in comparison with the core CdS NPLs. The fast decaying excited states of the NPLs are distributed over the CdS/ZnSe interface and slow down; the larger lifetimes allow for their potential utilization in applications requiring charge separation.