Effects of the incorporation of carbon powder into nanostructured TiO2 film for dye-sensitized solar cell

A nanoporous electrode was prepared by incorporating various amounts of carbon powder (Vulcan X-72) into TiO2 paste. To remove the black-colored carbon elements, high-temperature (550 °C) thermal treatment was required for a long period of time (from 30 to 50 min). In this way, a nanoporous TiO2 electrode with a high specific surface area and high porosity was formed after the incorporation of the carbon powder. Especially, the sample containing 1 wt% of carbon powder exhibited the best performance: a Voc of −0.72 V, a Jsc of 12.69 mA/cm2, a fill factor of 62% and an efficiency of 5.6%. Furthermore, the charge recombination between the photoinjected electrons from the excited dye and the I3− ions in the electrolyte induced by the enhanced surface was investigated by cyclic voltammetry and dark current measurements. In addition, mechanically stable TiO2 films were formed in the range of carbon powder contents used in this study. From the above results, it can be concluded that the modification of the TiO2 electrodes with a suitable carbon powder allows them to be used in dye-sensitized solar cells with improved performance and minor side effects.