One–step synthesis of Cu3BiS3 thin films by a dimethyl sulfoxide (DMSO)–based solution coating process for solar cell application

A large–grain and highly crystalline Cu3BiS3 thin film is successfully prepared by a dimethyl sulfoxide (DMSO)–based solution coating process. Without involving post sulfurization, Cu3BiS3 absorber with grain size of ~ 1 µm has been achieved via a short-time drying of spin–coated precursor film on a hot plate at relatively low temperatures (< 300 °C). Our Cu3BiS3 film exhibits a direct band gap of 1.47 eV with high absorption coefficients (~ 7 × 104 cm−1). Hall effect measurements reveal a p–type conductivity with hole concentration of ~ 1016 cm−3 and mobility of 52.83 cm2/(V s). Moreover, an initial Cu3BiS3 thin film solar cell with the device structure of glass/Mo/Cu3BiS3/CdS/ZnO/ITO/Al is fabricated, achieving a definite conversion efficiency of 0.17%. The mild preparation condition promises great potential of current method in realizing Cu3BiS3 solar cells on temperature-sensitive substrates such as flexible polymer through an energy efficient way. The Cu3BiS3 has thus been presented as a promising absorber material for solar cell applications.