A DFT and TDDFT Study of PCM Effect on N3 Dye Absorption in Ethanol Solution

Abstract

Dye Sensitized Solar Cell (DSSC) is one kind of low-cost third generation solar cell which employed organic or complex dye molecule as photon harvester. [Ru(H2dcbpy)2(SCN)2], known as N3 dye, one of the best sensitizer for DSSC, was the focus of this research. All calculations were carried out with Gaussian03, using B3LYP hybrid functional DFT and TDDFT for ground state geometry optimization and excited states calculations respectively. Basis setused in all calculations was 3-21G∗ for all elements. Polarized Continuum Model was used for modelling the complex in ethanol solution. Combination of 3-21G∗ basis set with PCM in N3 dye calculation achieve the better approach regarding to experimental absorption spectra. The last two maximum absorption peaks dominated by charge transfer excitation are red shifted in ethanol solution with respect to the gas phase. Electronic polarization between complex and solvent caused the structure to relax, permitting a greater charge separation.