Modification of TiO2 with sodium borohydride and its influence on photovoltaic cell performance

Although TiO2 has been widely used as the illumination anode in quantum dot sensitized solar cells (QDSSCs), its inherent low photovoltaic conversion efficiency remains a challenge. This study designed and prepared black rutile phase TiO2 (B-R TiO2) using sodium borohydride as a reducing agent, and utilized it as a photoanode in quantum dot-sensitized solar cells (QDSSCs). The findings illustrated that the modification of rutile phase TiO2 through the reduction method led to changes in its surface structure which in turn affects its band structure and optical absorption properties. The increase in surface oxygen vacancy concentration resulted in an enhancement of light absorption intensity, leading to an enhanced photovoltaic conversion efficiency. Subsequently, when employed as a photoanode in QDSSCs, the photovoltaic conversion efficiency (PCE) increased from an initial 1.77