Cu1.8S@CuS composite material improved the photoelectric efficiency of cadmium-series QDSSCs

Abstract An efficient and newly-built strategy is demonstrated in this page to produce counter electrode, which contains two mixtures (Cu1.8S and CuS), for QDSSCs. Compared with those of Cu2S CE, the higher electrochemical activity and lower charge transfer resistance of solar cells equipped with Cu1.8S@CuS CE result in a prominent development in photovoltaic characteristics. All the η, Voc and FF exhibit remarkable improvements whether in CdS or Mn2+–CdS QD sensitization system. In CdS QD sensitization system, current–voltage curve results indicate that the η and Voc of cells with Cu1.8S@CuS-120 CE are 1.49 and 1.17 times higher than those with Cu2S CE, respectively. FF is increased from 0.32 to 0.40. Besides, in Mn2+–CdS QD sensitization system, the η and Voc of cells with Cu1.8S@CuS-120 CE are 1.52 and 1.15 times higher than those with Cu2S CE, respectively. Furthermore, FF is increased from 0.33 to 0.42. Electrochemical impedance testing results reveal that the QDSSCs prepared with composite Cu1.8S@CuS-120 CE have lower resistance qualities.