A DFT/TD-DFT Study on Pyridine-Anchored Schiff Base Molecules for DSSC Applications

Abstract

The primary objective of this research is to examine the Schiff bases produced from pyridine-anchored molecules, with a specific focus on their potential utilization in dye-sensitized solar cells (DSSCs). The electrical, spectroscopic, and photovoltaic properties of dyes incorporating a pyridine anchor were calculated utilizing DFT and TD-DFT methodologies. The geometries, electronic characteristics, and photovoltaic properties of the dyes under investigation were evaluated using DFT-B3LYP/6-311++G(d,p) quantum chemical simulations. The excitation energies and UV-Vis spectra of the dyes have been computed utilizing the TD-DFT-B3LYP/6-311++G(d,p) methodology and the conductor-like polarizable continuum model (C-PCM). The electron injection and dye regeneration processes are contingent upon the energy levels of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of these dyes. The investigation focused mainly on four fundamental components exhibiting robust interconnections and equivalent significance: light-harvesting efficiency (LHE), electron injection free energy (ΔGinject), and reorganization energy. The determined HOMO energy levels are observed to be lower than the redox potential, indicating that the suggested dyes possess the capability to acquire electrons from redox and successfully undergo dye regeneration. Furthermore, the LUMO of the dyes exhibits a more significant negative energy level in comparison to the conduction band of TiO2. Thus, it demonstrates that the transfer of electric charge from the LUMO level to TiO2 is thermodynamically favorable. The more considerable negative ΔGinject value obtained by calculation suggests that Dye-1 may have a higher ability to inject charge.