Unveiling the role of Cr-doped biphasic TiO2 photoanode for improving the photovoltaic performance of dye-sensitized solar cell

Abstract

Two significant factors that improve dye-sensitized solar cells’ (DSSCs’) performance are increased electron concentration and effective charge transport. In the present work, pristine and Cr-doped biphasic TiO₂ in various phase ratios were prepared and utilized as the photoanode of the DSSC. Doping created oxygen vacancies, leading to phase transformation at lower calcination temperatures. The doped biphasic TiO₂ photoanode’s photovoltaic performances were superior to its pristine counterparts. The sample with 70% anatase and 30% rutile (CrTi-400) showed the highest photoconversion efficiency (PCE) compared to the rest. The low crystallite size of CrTi-400 facilitated a higher dye adsorption, leading to a better photo-excited electron injection. The photoelectrochemical study revealed an efficient charge transport in CrTi-400, and this, coupled with the improved electron concentration due to the oxygen vacancies created via Cr doping, enhanced the photocurrent (J_SC). The synergy between doping and biphasic junction improved the structural, optical, and electrical properties, improving its J_SC and overall photovoltaic performance. This study showcases a novel strategy for enhancing the photoanode performance of the TiO₂-based DSSC by utilising the synergy of doping and heterojunction.