Untangling the effect of π-conjugation length on the opto-electronic properties of reactive dye-based sensitizer.

Reactive dyes exhibit suitable opto-electronic properties, making them promising for dye-sensitized solar cell (DSSC) applications. The present study uses reactive orange 16 dye to design an efficient dye sensitizer for DSSC application using a donor–π–acceptor concept. The sensitizer structures and their electronic and optical properties were investigated using density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. The molecular electrostatic potential maps, HOMO–LUMO distributions, and density of states plots were obtained for the optimized geometry. The analysis showed that the electronic properties of reactive orange 16 are enhanced due to the π-linkage, responsible for extending the conjugation length of the system. The TD-DFT calculations showed a bathochromic shift in the absorption spectra due to the introduction of the π-linker. The shift confirmed the conjugation's role in enhancing the sensitizers' electronic properties. The transitions were π → π* and n → π*, and the transition with maximum oscillator strength was assigned to the H → L excitation. The study showed that donor–π–acceptor concept-based sensitizers derived from reactive dyes favor DSSC applications. Hence, this study's findings could be used to design and develop more efficient dye sensitizers based on reactive dyes. [ABSTRACT FROM AUTHOR]