Incorporation of Bi sintering aid to TiO2 photoanode for low temperature dye sensitized solar cell

Abstract The low conversion efficiency for low temperature dye sensitized solar cells (DSSCs) due to poor interparticle contact and charge transfer of TiO 2 photoanode has been an issue for the solar cell. Therefore, the research aims to combat the issue with the implementation of bismuth (Bi) nanoparticles as sintering aid to the TiO 2 photoanode. The addition of Bi sintering aid was found to form necks at the TiO 2 -Bi matrix seen in the morphological studies, despite the low sintering temperature of 200°C, due to the low melting point of Bi (271.4°C). The formation of these necks improved the interparticle contact and charge transfer of the photoanode that was observed in the electron transfer studies. Photoanodes with Bi sintering aid yielded lower charge transfer resistance (R CT ) and series resistance (R S ) than bare TiO 2 photoanode by 15%-31%. The R CT and R S of TiO 2 -4%Bi photoanode (R CT =7.244 kΩ/cm 2 , R S =14.64 kΩ/cm 2 ) was even almost comparable to the commercially prepared TiO 2 photoanode at high temperature of 450°C (R CT =5.125 kΩ/cm 2 , R S =10.34 kΩ/cm 2 ). Thus, indicating the potential for this approach in enhancing the overall performance of flexible low temperature DSSC in the future.