Theoretical Investigation of Anthocyanidin Aglycones as Photosensitizers for Dye-Sensitized TiO2 Solar Cells

The aim of this study is to analyze dye electronic properties of anthocyanin aglycones to be used as photosensitizers for TiO2solar cells. The dye properties will be examined by the density functional theory (DFT) method at IEF-PCM(UFF)/B3LYP/6-31+G(d,p) levels under ethanol and water environments. The results show that the position of LUMOs of all dyes lying over TiO2ECBwill facilitate good electron transfer while their HOMOs, which are lower than the electrolyte redox potential energy, can facilitate good oxidized-dye regeneration. Flavilium cation dye is the best anthocyanidin aglycone due to the best electron injection spontaneity of -0.807 eV as well as the highest open circuit voltage of 1.669 V. On the other hand, quinonoidal base dye gives the best light harvesting efficiency of 69.24% due to the best oscillating strength character. Moreover, the solvent effect is the important aspect regarding the dye oxidation potential stabilization as well as the electron injection driving force.