Speakers
Description
The efficiency of Dye-Sensitized Solar Cells (DSSC) as one of solar energy harvesting technology is highly dependent on the optical and electronic properties of the dye compounds used. Galangin as a natural flavonoid compound that is abundant in ginger plants has that potential, but its direct application is hindered by a wide energy gap and an absorption peak that is still in the ultraviolet region, even though its LUMO energy level is already above the conduction band TiO2. This research aims to optimize the properties of galangin computationally using the DFT method at the B3LYP/def2-SVP level of theory. Structure engineering is done through the variation of π-spacer (thiophene and furan) and acceptor group (4-ethynyl benzoic acid and cyanoacetic acid). Simulation results show that the combination of thiophene and cyanoacetic acid (GTS) provides the best optoelectronic performance. The efficient electron delocalization properties of thiophene, combined with the strong electron attraction of cyanoacetic acid, succeeded in narrowing the GTS energy gap significantly. Furthermore, the effect of the π-spacer chain length was explored by varying the number of thiophene units (Tn) of GTS. The extension of the thiophene-conjugated bridge significantly shifts the absorption spectrum toward longer wavelengths (redshift). Among all the evaluated groups, the GTS group exhibits the largest maximum absorption wavelength (max), effectively expanding the light absorption capacity in the visible spectrum. The T4 molecule produces the highest total dipole moment of 6.70 D, indicating the most effective charge separation between the donor and acceptor. The synergy between the maximum max shift, high oscillator strength, and superior dipole moment enhances the intramolecular charge transfer, enhances interfacial charge injection, and suppresses electron recombination at the TiO2/sensitizer interface. Therefore, the T4 molecule is recommended as the most optimal and high-potential sensitizer candidate for DSSC applications.
