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 TiO۲ surface. All calculations were performed at the B۳LYP level of theory using the ۶-۳۱۱G(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.

کلیدواژه ها:

DFT calculations ، Dye-sensitized solar cells ، TiO۲ ، Gaussian ، Alizarin ، Carbazol ، TD-DFT