Herein, we report some key results related to the photovoltaic properties of a novel dye structure with a double triphenylamine donor and an indoloquinoxaline as the subordinate acceptor (QX22; Fig. 1). To find out whether this dye is applicable to the dye-sensitized solar cell (DSSC) and whether charge transfers are possible in the DSSC, natural bond orbital (NBO) analysis and ground/excited state studies were applied [1]. To obtain photovoltaic parameters, density functional theory (DFT) [2] and time-dependence DFT (TD-DFT) computations were used [3]. Since the LUMO energy level of QX22 is upper than the conductor band (CB) of TiO2 and its HOMO state is lower than the oxidation potential of (I-/I3-) electrolyte, it can be applied as a sensitizer in the DSSC. Negative values of Gibbs energy of the electron/hole injections (∆Ginj./∆Greg.) show an efficient charge transfer in the DSSC. Negative value of ∆Ginj means that electron easily transfers from the dye to TiO2, which can prevent the charge recombination. Also, ∆Greg. values show a proper regeneration process in the DSSC, which can prevent this photovoltaic system from quenching process.

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