Photovoltaic Effect of Metal-Doped TiO2 Nanoparticles for Dye-Sensitized Solar Cells

Abstract

Crystalline anatase TiO2 nanoparticles (NPs) synthesized by a sol-gel method were used as photoelectrodes in dye-sensitized solar cells (DSSCs). In order to improve the electrochemical properties such as the open circuit voltage (Voc) and the rate of electron transfer, various amounts of Al and Zn were doped into TiO2 NPs. Al doping of TiO2 NPs successfully improved the photovoltaic performance of the DSSCs as seen in the Voc of 0.79 V for these electrodes. The Zn-doped TiO2 NPs exhibited faster electron transport than pure TiO2 or Al-doped TiO2 NPs. The photovoltaic efficiency (η) of pure TiO2 NPs, 4 mmol Al-doped TiO2 NPs, and 3 mmol Zn-doped TiO2 NPs-based DSSCs are 3.90, 5.86, and 5.58%, respectively. In order to improve the Voc, Jsc, and electron transfer rates simultaneously, the 4 mmol Al-doped TiO2 NP and 3 mmol Zn-doped TiO2 NP powders were mixed together and used for the preparation of photoelectrodes. The η of the mixed Al/Zn-doped TiO2 NPs-based DSSC was 7.12%, while the Voc, Jsc, and electron transport times were 0.75 V, 14.38 mA cm−2 and 3.112 × 10−4 s, respectively.