Exploring the effect of different coumarin donors on the optical and photovoltaic properties of azo‐bridged push‐pull systems: A theoretical approach

We report the theoretical modeling of various azo‐bridged coumarin‐purpurin systems. The effect of varying the donor (coumarin) part of this D‐π‐D‐π‐A system was analyzed in terms of opto‐electronic and photovoltaic parameters such as HOMO, LUMO, HOMO‐LUMO energy gap, λ max , light harvesting efficiency, charge injection efficiency, open voltage, reorganization energy by employing density functional theory as incorporated in Gaussian 03 set of codes. The dye‐TiO 2 adsorbed systems were also studied using the same level of theory. It was found that just by varying the donor, although of same nature, there is a marked effect on the efficiency parameters of the dye sensitized solar cells based on such dyes. Also, the dye molecules were found to be good sensitizers for TiO 2 semiconductors.