Effect of Flavone and Isoflavone in the Triphenylamine-Based Sensitizers for Dye-Sensitized Solar Cell Applications: DFT and TD-DFT Approach

Several metal-free organic sensitizers have been designed for dye-sensitized solar cell applications. The effect of flavone and isoflavone in the triphenylamine sensitizers was investigated in the present work. The dyes with different donors are analyzed by density functional theory and time-dependent density functional theory. The various parameters such as geometry, electronic structure, highest occupied molecular orbital and lowest unoccupied molecular orbital, light harvesting efficiency and electronic absorbance spectrum of the designed sensitizers were analyzed. The absorption bands in the visible and near-Ultra Violet (UV) region are correlated to photoinduced electron transfer process. The effect of flavone on the triphenylamine donor retards the photo degradation of the dye. It gives hyperchromic and bathochromic shift in the dyes and it also acts as UV filters. Free energy change for electron injection and dye regeneration was calculated. The results show that the designed dyes may be an efficient sensitizer for DSSC applications.