Bournonite CuPbSbS3: An electronically-3D, defect-tolerant, and solution-processable semiconductor for efficient solar cells

The absorber layer is a key component of thin-film solar cells. Based-on the recently-proposed electronic dimensionality concept, a promising solar cell absorber material should be electronically high-dimensional, as is the case for all the mainstream absorbers, such as Si, GaAs, Cu(In,Ga)Se 2 , CdTe, and CH 3 NH 3 PbI 3 . In this work, we propose an electronically three-dimensional semiconductor, bournonite CuPbSbS 3 , as a prospective efficient solar cell absorber material. Our density functional theory calculations indicate that CuPbSbS 3 exhibits desired optoelectronic properties, such as a nearly direct bandgap, high optical absorption coefficients, appropriate p -type doping, and defect tolerance . Experimentally, we developed a butyldithiocarbamate acid (BDCA) solution process for depositing high-quality CuPbSbS 3 thin films and built the first CuPbSbS 3 thin film solar cells. Our CuPbSbS 3 -based solar cells achieved a preliminary power conversion efficiency of 2.23% (open circuit voltage of 699 mV), highlighting the potential of this semiconductor for thin film photovoltaics .