Dye-sensitized solar cell (DSSC) or Graetzel cell is a less expensive solar cell belonging to the group of thin film solar cells. The advantages of DSSCs are mainly due to low cost production, low energy payback time, flexibility, performance at diffuse light and multicolor options. The present review gives a detailed summary and evaluation of the DSSCs. The role of TiO2 in the fabrication process as a photoanode to improve the high performance of DSSCs also discussed in detail. Structural modifications during the fabrication of the device are discussed along with the factors affecting to improve the efficiency of the DSSCs. Wide ranges of dyes were identified using Density Functional Theory (DFT) for HOMO-LUMO calculations. On the other hand, Doping plays a major role on the band structure and trap states of TiO2, which in turn affect the important properties such as conduction band energy, charge transport, recombination and collection. High-throughput methods may also be employed to achieve a rough prediction on the suitability of dopants for the specific synthesis methods. It was found that nearly every employed photoanode can be used to increase the device performance, indicating that the improvement in efficiency is not so much caused by the dopant itself. The current available knowledge on TiO2 as a Photoanodic material provides remarkable light harvesting efficiency in connection with perovskite solar cells and DSSCs.
