Enhanced photocatalytic efficiency of layered CdS/CdSe heterostructures: Insights from first principles electronic structure calculations

TL;DR

This study uses first principles calculations to analyze the electronic structure of CdS/CdSe heterostructures, revealing their potential to enhance photocatalytic efficiency under visible light.

Contribution

It provides a detailed theoretical insight into the band structure and charge transfer mechanisms of CdS/CdSe heterostructures, highlighting their advantages for photocatalysis.

Findings

CdS/CdSe forms a type-II heterostructure

Type-II alignment improves charge separation

Enhanced photocatalytic efficiency under visible light

Abstract

Metal sulfides are emerging as an important class of materials for photocatalytic applications, because of their high photo responsive nature in the wide visible light range. CdS in this class of materials, have a direct band gap of 2.4 eV, have gained special attention due to the relative position of its conduction band minimum, which is very close to the energies of the reduced protons. However, the photogenerated holes in the valence band of CdS are prone to oxidation and destroy its structure during photocatalysis. Thus constructing a CdS based heterostructure would be an effective strategy for improving the photocatalytic performance. In this work we have done a detail theoretical investigation based on hybrid density functional theory calculation to get insight into the energy band structure, mobility and charge transfer across the CdS/CdSe heterojunction. The results indicate that CdS/CdSe forms type-II heterostructure that has several advantages in improving the photocatalytic efficiency under visible light irradiation.