In this research, photovoltaic properties of the indoloquinoxaline-based dyes, QX22-QX25, as the (D)2-A-π-A structure were investigated, dynamically and kinetically. In these structures, two acceptors, cyanoacrylic acid and 2-(1,1-dicyanomethylene) rhodanine, CCRD, and two π-spacers, furan and thiophene have been used. Density functional theory (DFT), time-dependent DFT (TD-DFT) and natural bond orbital (NBO) were used to evaluate the electronic structures and excited state properties of these metal-free organic dyes. The analysis of the dynamics/kinetics of the photovoltaic parameters of the corresponding dye-sensitized solar cells (DSSCs) shows that each moiety of the D-π-A system has a more specific effect on one of the photovoltaic properties. On the basis of the obtained results, linear correlations of the incident photon to current conversion efficiency (IPCE) to the kinj./ΔGinj. are stronger than that of light harvesting efficiency (LHE). Moreover, a red shift in the absorption spectra and a higher LHE in the DCRD-based dyes are observed. Although, thiophene-based dyes showed an improved exciton dissociation rate, Rd, but, QX22 and QX23 are the preferred candidates to be applied in solar cells due to their optimized quantum chemistry properties and maximum IPCE.

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