theoretical insights into alizarin-carbazole dyes for improved dssc performance using dft/td-dft

To achieve significant advancements in light-harvesting efficiency for dye-sensitized solar cells (dsscs), this investigation explores the potential application of six novel hybrid alizarin-carbazole dyad molecules. these dyads incorporate strategically positioned π-conjugated spacer segments that have been meticulously functionalized with either electron-donating or electron-withdrawing groups. a comprehensive computational analysis was undertaken to elucidate the optoelectronic properties of the target molecules, both in their isolated states and after adsorption onto a tio2 surface. all calculations were performed at the b3lyp level of theory using the 6-311g(d) basis set to obtain critical parameters such as the homo-lumo energy gap (eg), light absorption wavelength (λ), transition energy (ev), and oscillator strength (f). the results showed that the photophysical and photo-electrochemical properties of designed dyes were improved by introduction of electron-rich heterocyclic rings as a π-spacer moiety, which led to a reduction in the band gap of the designed dyes and, as a result, a red-shifting of light absorption spectra and an increase in the dsscs energy conversion efficiency. this in-depth theoretical investigation is expected to provide valuable insights for the rational design and optimization of novel organic dyes, ultimately leading to the development of high-performance dsscs.