Experimental and theoretical insight into DSSCs mechanism influenced by different doping metal ions

Mesoporous TiO2 doped with Cu2+, Mn2+, and Ni2+ ions nanomaterials with 0.4% content of dopant ions were synthesized via the optimized sol-gel method. Experimental results were compared with an extensive theoretical study of doped-TiO2 nanoparticles using density functional theory extended by Hubbard correction. Structural analyses performed indicate anatase structure (with minor impurity of brookite) of spherical-shaped nano-particles with a size below 15 nm. Further, XPS and EPR analyses confirmed the doping of metal ions into TiO2 and the formation of oxygen vacancies. The characteristic narrowing of the energy bandgap was observed with a higher concentration of dopants than 0.4%. Nanomaterials were used to fabricate solar cells sensitized with N3 dye. Comprehensive analysis of photovoltaic results combined with theoretical calculations has been provided to propose a working principle mechanism of electron transport in the investigated nanomaterials. Each metal ion used during the nanomaterials' synthesis caused a different effect on the DSSC performance resulting from the structure of their energy bandgap. TiO2 doped with Cu2+ and Mn2+ indicates a remarkable decrease in conductivity instead of TiO2:Ni2+. Therefore, the most effective nanomaterial for DSSC application turned out to be TiO2:0.4 %Ni2+ with a photoconversion efficiency improvement compared to standard P25 titania.