A first principle investigation of the formation, stability and electronic properties of acanthite Cu₂S with comparison to other Cu₂S known phases toward a promising application in the field of photovoltaic.

Cu₂S is a well-known semiconductor in the field of renewable energy. As a solar absorber material, its application in thin film solar cell have been extensively studied over the years. It had shown nearly 10% efficiency in the past. However, excessive p-type doping resulted from spontaneous Cu vacancy formation makes the material unstable for proper usages in the field of photovoltaic. In this work, we have shown that a relatively new predicted phase of Cu₂S known as acanthite phase is energetically as favorable as its well-known low chalcocite phase to form at 0K. We have used density functional theory as the framework for a systematic study to compare its formation, electronic and optical properties with other known Cu₂S phases. Also, we have shown that Ag alloying with Cu₂S can help to reduce Cu vacancy formation tendency in the crystal. Finally, we have compared this theoretically predicted acanthite phase with known minerals like AgCuS and Ag₃CuS₂ with regard to its application as a potential photovoltaic material.