To obtain molecular information about the electronic transitions and energy conversion efficiency in some of the carbazole and yldiazenylphenylbased dyes, MC, FC, FB, and PY photosensitizers and dye-I2 complexes were studied. The obtained results show that the charge transfer processes and final efficiency of the studied DSSCs are strongly affected by the molecular properties and polarizability of the sensitizers under the incident radiation. A decrease in the electrophilicity and electronic chemical potential of the Journal Pre-proof 2 carbazole-based sensitizers increases the ability of the dye to overcome the energy barrier of the electron injection. In contrast to the carbazole-based sensitizers, PY dye shows proper spectroscopic properties, faster exciton dissociation, and less interfacial charge recombination, which decrease the shortcomings and increase the outcome voltage. Finally, based on the obtained energy conversion efficiencies of the dyes, MC is proposed as the best candidates to be applied in the DSSC.

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