Anthocyanin modified triphenylamine based organic sensitizer for dye sensitized solar cells (DSSC) - A theoretical approach

Abstract

Three triphenylamine based dyes (Dye 1, 2 & 3) and three anthocyanin modified triphenylamine based dyes (Dye 4, 5 &6) are designed and the geometry, electronic structure and absorption spectra of newly designed dyes were investigated by density functional theory (DFT) and time dependent density functional theory (TD-DFT) with the Becke 3-Parameter-Lee-Yang-Parr (B3LYP) functional, where the 6-311++G (d, p) basis set was employed. All calculations were performed using the Gaussian 09 software package. The lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) energy level of these dyes could ensure the positive effect on the process of electron injection and dye regeneration. The LUMOs are just above the conduction band of TiO2 and their HOMOs are under the reduction potential energy of the electrolytes (I−/I3−) which can facilitate electron transfer from the excited dye to TiO2 and charge regeneration process after photo oxidation respectively. The simulated absorption spectrum of dyes matches with solar spectrum. The simulated absorption spectrum of dyes shows better absorption. The calculated quantum mechanical results shows that among all six dyes, the “dye 6” can be used as potential sensitizer for DSSC.