Electronic Structure and Phase Stability of Ag and Sn Doped Cu2s: A DFT Study

Abstract

Cu2S is an important solar absorber material. Despite having excessive Cu vacancy formation tendency and being a degenerate semiconductor, it has gained wide attention due to its non-toxicity, earth abundance, suitable band gap and previously shown nearly 10% efficiency in thin film solar cells. A new theoretical phase of Cu2S, a DFT predicted acanthite like phase, has shown that Ag doping can help to reduce Cu vacancy formation tendency without altering its electronic structure much. Hence, doping Cu2S with suitable cations warrants more studies on its electronic structure and phase stabilities. Here, we are going to present a systematic DFT study for Ag and Sn doped Cu2S acanthite like and low chalcocite phases to explore the electronic structures, optical properties, Cu vacancy formation tendency, and crystal phase stabilities.