On the study of dye-sensitized solar cells with high light harvesting efficiency and correlation of its chemical reactivity parameters with overall performance

In this study, thirteen donors with the same spacer and acceptor have been tested to model dyes for dye-sensitized solar cell. Amongst the thirteen donors, 7,7,13,13-tetramethyl-8,9,12,13-tetrahydro-2H,5H,7H,11Hpyrano[2′,3′:4,5]pyrano[2,3-f]pyrido[3,2,1-ij]quinoline-2,5-dione is found to possess the highest oscillator strength amongst the other dyes in first excited state. This donor has been studied further with five different acceptors to make ten dyes (by also considering their conformers formed by twisting the dye by 180 ∘ about the bond joining the donor with the spacer) to make dyes of type-I, among which the dye with rhodanine acetic acid acceptor and its conformer have the lowest HOMO–LUMO energy gap E g , highest absorption wavelength in the absorption spectrum with high oscillator strength and low exciton binding energy in the first excited state as compared to the other eight dyes considered here. The rhodanine acetic acid-based dyes have shown to outperform all the other four acceptor-based dyes in terms of chemical reactivity parameters. All the ten dyes when tested further with the inclusion of an extra benzene spacer show enhanced overall performance, with the rhodanine acetic acid-based dyes showing the most planarity, highest absorption wavelength, more suitable reactivity parameters, etc. Correlation studies between the solar cell parameters and chemical reactivity parameters have also been conducted where a direct relationship between the chemical hardness of the dye and open circuit voltage has been observed.