Solution-processed CuSbS₂ solar cells based on metal–organic molecular solution precursors

Developing earth-abundant and low-toxic light absorber materials is crucial for next-generation photovoltaics. In this article, a simple solution-process method for the deposition of CuSbS₂ thin film is presented. An equimolar mixture of Cu₂O and Sb₂O₃ was dissolved in butyldithiocarbamic acid, forming a thermally degradable metal–organic molecular solution. Uniform and phase-pure CuSbS₂ thin films can be obtained by spin coating this precursor solution followed by a fast annealing process in an inert gas environment. Preferential crystal growth of (111) lattice planes was observed in films prepared at annealing temperature of more than 290 °C. The films possess a direct band gap of 1.6 eV with high absorption coefficient. CuSbS₂ planar heterojunction solar cells of FTO/CdS/CuSbS₂/Au structure were assembled achieving a power conversion efficiency of 0.68% under one sun illumination. This metal–organic molecular solution precursor provides a simple method to fabricate multicomponent inorganic chalcogenide films for photovoltaic application.