Influencing Mechanism of the Selenization Temperature and Time on the Power Conversion Efficiency of Cu2ZnSn(S,Se)(4)-Based Solar Cells

摘要

Cu2ZnSn(S,Se)(4) (CZTSSe) films were deposited on the Mo-coated glass substrates, and the CZTSSe-based solar cells were successfully fabricated by a facile solution method and postselenization technique. The influencing mechanisms of the selenization temperature and time on the power conversion efficiency (PCE), short-circuit current density (J(sc)), open-circuit voltage (V-oc), and fill factor (FF) of the solar cell are systematically investigated by studying the change of the shunt conductance (G(sh)), series resistance (R-s), diode ideal factor (n), and reversion saturation current density (J(0)) with structure and crystal quality of the CZTSSe film and CZTSSe/Mo interface selenized at various temperatures and times. It is found that a Mo(S1-x,Se-x)(2) (MSSe) layer with hexagonal structure exists at the CZTSSe/Mo interface at the temperature of 500 degrees C, and its thickness increases with increasing selenization temperature and time. The MSSe has a smaller effect on the R-s, but it has a larger influence on the G(sh), n, and J(0). The PCE, V-oc, and FF change dominantly with G(sh), n, and J(0), while J(sc) changes with R-s and G(sh), but not R-s. These results suggest that the effect of the selenization temperature and time on the PCE is dominantly contributed to the change of the CZTSSe/CdS p-n junction and CZTSSe/MSSe interface induced by variation of the quality of the CZTSSe film and thickness of MSSe in the selenization process. By optimizing the selenization temperature and time, the highest PCE of 7.48% is obtained.