Theoretical study of anthoxanthin dyes for dye sensitized solar cells (DSSCs)

Abstract

Systematic theoretical investigations of selected anthoxanthins belonging to the Flavone and Flavonol families are carried out with the aim of identifying the dye with the optimum properties for use as sensitizers in dye sensitized solar cells (DSSCs). The ground-state geometries of these dyes in the gas phase are fully optimized by Density-Functional Theory (DFT). Time-Dependent Density Functional Theory (TDDFT) with Polarizable Continuum Model (PCM) for solvent effects is invoked to predict the vertical electron excitation energy, maximal absorption wavelength, oscillator strengths, light harvesting efficiency (LHE), free energy change of electron injection $$\left( {\Delta } G^{inject}\right) $$ΔGinject and dye regeneration $$\left( {\Delta } G_{dye}^{regen}\right) $$ΔGdyeregen. The charge transfer from the excited state and charge regeneration in the ground state of the dyes is also identified. All these calculations were performed in the gas phase and with dimethyl sulfoxide (DMSO) as solvent. Finally, the electron transfer characteristics between the dye's lowest unoccupied molecular orbital (LUMO) and the conduction band of $$\hbox {TiO}_{2}$$TiO2 are investigated. The study reveals that the electron transfer character of these dyes can be made suitable for applications in DSSCs with structural modifications.