(Cu 2 S 2 )(Sr 3 Sc 2 O 5 )−A Layered, Direct Band Gap, p-Type Transparent Conducting Oxychalcogenide: A Theoretical Analysis.

Development of a p-type TCO to rival the high-performance n-type TCOs presently utilized in many applications is one of the grand challenges for materials scientists. However, most of the p-type TCOs fabricated to date have suffered from limited hole mobilities, low conductivities, and indirect band gaps. Recently, [Cu 2 S 2 ][Sr 3 Sc 2 O 5 ] has been identified as a possible p-type TCO material, with improved hole mobility. In this article, we study the geometry and electronic structure of [Cu 2 S 2 ][Sr 3 Sc 2 O 5 ] using both GGA + U and HSE06 . We show conclusively that [Cu 2 S 2 ][Sr 3 Sc 2 O 5 ] is a direct band gap material, with a hole effective mass at the valence band maximum that indicates the potential for good p-type conductivity, consistent with the reported experimental results. These results are discussed in relation to other p-type TCO materials.