Novel gamma-irradiated chitosan-doped reduced graphene-CuInS2 composites as counter electrodes for dye-sensitized solar cells

To address the issues associated with traditional counter electrodes, a novel gamma-irradiated chitosan-doped reduced graphene-CuInS2 composite (Chi@RGO-CIS) was used as the counter electrode (CE). The system was fabricated following a simple hydrothermal method. The prepared Chi@RGO-CIS was characterized by various spectroscopic and microscopic techniques. The synergistic effect between chitosan, CuInS2, and reduced graphene oxide can help in producing a large surface area. It can also help in the generation of catalytic sites toward I-/I-3-redox electrolytes. We used a composite (based on electrical considerations) to study the effect of the amount of graphene on the characteristics and photovoltaic efficiency of the Chi@RGO-CIS composites. The solar cell assembled with 1.5% Chi@RGO-CIS exhibited an efficiency of 12.21%. The efficiency was higher than that of a Pt-based device (9.96%) fabricated under the same conditions. Hence, Chi@RGO-CIS can be potentially used as the CE of dye-sensitized solar cells (DSSCs). It can be used as a substitute for Pt in DSSCs.