Enhancement in Photovoltaic Performance of Dye Sensitized Solar Cells Using Cu and Cu:Ag Co-Doped TiO₂ Photoanode

Dye Sensitized Solar Cells (DSSCs) are low cost solar cells offering big room for improvements in its photovoltaic performance by maneuvering semiconductor properties, dye adsorption, electrolyte stability etc. For the first time, we have co-doped TiO₂ with silver (Ag) and copper (Cu) to enhance both charge collection and light absorption as well as reduce recombinations for DSSCs. For high solar cell efficiency 3wt% Cu and 3wt% Cu:Ag doped TiO₂ nps were successfully prepared for Dye Sensitized Solar Cells (DSSCs). Modified photoanode was prepared using surface adsorbed N719 dye on doctor blade coated TiO₂, Cu:TiO₂ and Cu:Ag:TiO₂ thin films. It was observed that optimum doping concentration of Cu and silver was 3wt% each. DSSCs with Cu:Ag:TiO₂ thin film showed higher conversion efficiency under full sunlight illumination when compared to DSSCs assembled using Cu:TiO₂ and undoped TiO₂. The obtained efficiencies for DSSCs with undoped TiO₂, Cu:TiO₂ and Cu:Ag:TiO₂ photoanodes were 2%, 2.7% and 4.5% respectively. Solar cells assembled with Cu only doped TiO₂ electrode when compared with cells assembled using pristine TiO₂, showed an increase in Voc while Jsc was decreased Furthermore, cells doped with both Ag and Cu showed enhancement in both V_oc and J_sc. The enhancement in cell performance has been discussed in context of morphology, crystal phase, presence of bonds etc. in nanoparticles. Considering overall better performance, Cu:Ag doped TiO₂ photoanodes can be considered as potential photoanodes in DSSCs.