According to problems originating from the use of fossil fuels to generate electricity, solar energy has been considered. One method that can be used for this issue is dye-sensitized solar cell technology. There are several ways to increase the efficiency of a cell which one of them is choosing appropriate dye molecules. In this paper, the FT dyes series were selected and the effect of electronegative group as well as alkyl chain length is examined. All DFT computations were performed with plane-wave basis set. According to the results, substituting an electronegative group leads to reducing the difference between HOMO energy and potential energy of I-/I3- in order to facilitate electron transfer from I-/I3- to the stable energy. Energy difference between LUMO of dye sensitizer and conduction band of semiconductor TiO2 decreases as the substitution takes place on the anchoring bidentate ligand of Ru(II) complex. Whatever the difference is less; dye regeneration will be favored and cell efficiency improves. In addition, FT57 dye is the most efficient during the considered dyes because of its appropriate electronic and quantum properties.

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