First principle calculation of the photophysical properties of silylated coumarins 120 and 151

The Ground and excited state properties of silylated coumarins 120 and 151 were obtained within the framework of density functional theory. We made a comparison between different properties of silylated and unsilylated coumarins 120 and 151. Silylation of dye molecules does not affect the transition energies considerably. However, an appreciable improvement was observed in oscillator strength. Using calculated results, we can conclude that silylation will results in better long-term photostability compared to its unsilylated counterpart due to their strong caging within the host matrix. Therefore, silylated molecules may become good candidates for solid state dye laser and dye sensitized solar cell.