Characterization of defects in copper antimony disulfide

Copper antimony disulfide (CuSbS 2 ) with the chalcostibite structure is a promising photovoltaic (PV) absorber material with several excellent measured optoelectronic properties, such as a solar matched band gap and tunable hole concentration. However, much less is known from an experimental perspective about defects in CuSbS 2 , even though the defects are critical for solar cell performance. Here, we explore the defect properties in CuSbS 2 thin film materials and photovoltaic devices using photoluminescence and capacitance-based spectroscopies, as well as first principles theoretical calculations. We measured three electrically and optically active acceptor defects in CuSbS 2 , and assigned them to the copper vacancies, sulfur vacancies, and/or copper on antimony antisites by comparison with theoretical calculations. Their activation energies, concentrations, and capture cross sections have been determined and compared to other chalcogenide absorber materials. These fundamental parameters should enable more accurate simulations of CuSbS 2 PV devices, paving the way for future improvements in CuSbS 2 solar cell efficiencies. Copper antimony disulfide (CuSbS 2 ) has several excellent bulk optoelectronic properties for photovoltaic absorber applications. Here, we report on the defect properties in CuSbS 2 thin film materials and photovoltaic devices studied using several experimental methods supported by theoretical calculations.