A doped heterojunction photoanode: a strategy-driven approach to improve the charge carrier dynamics and photoconversion performance of the TiO₂-based dye-sensitized solar cell

The synergy of doping and heterojunction in developing a doped heterojunction photoanode and its influence on DSSC performance are explored in the present work. Herein, Fe-doped biphasic TiO₂ heterojunctions are synthesized via a sol-gel process with varied anatase-rutile (A/R) phase ratios. The doped biphasic heterojunctions exhibited a superior photoconversion efficiency (PCE) compared to pristine counterparts, among which the photoanode with a 1.50 A/R ratio (FT-400) showed the highest efficiency. This can be attributed to the effective photon utilization of FT-400 due to the high surface area and low crystallite size coupled with better charge transport and reduced recombination losses. A higher value of J_SC and V_OC indicated a high electron concentration and a shift in the fermi level in the sample. The synergy of doping and heterojunction in TiO₂ photoanode leads to elevated photon absorption and effective charge transport and it opens up an era of research for photoanode improvement.