Transition divalent metal substitution in chalcopyrite CuInSe2 (In = Co, Ni, and Mn) counter electrode for dye-sensitized solar cell applications

The synthesis of low-cost and high electrochemical activity to regenerate electrolyte and to enhance the efficiency (counter electrodes (CE)) is of paramount importance for the DSSCs. To achieve the maximum power conversion efficiency of DSSCs with the low-cost counter electrode (CE), Cu- (In, Co, Ni, Mn)-Se-2 has prepared by hydrothermal method. The structural and chemical composition of Cu- (In, Co, Ni, Mn)-Se-2 was confirmed by XRD and XPS analysis. The charge transfer resistance of CuInSe2 (CIS), CuCoSe2 (CCS), CuNiSe2 (CNS), and CuMnSe2 (CMS) were 5.60, 11.50, 1.40, and 5.60 Omega (CNS < CIS < CMS < CCS), where CNS showed minimum charge transfer resistance, owing to the intrinsic electrochemical and electrical properties of Ni. The CNS (4.16 %) showed better photovoltaic efficiency which was 1.51 times higher than the CIS CE (2.65) based DSSCs.