ICSEM‐2025: Computational Insights on Optoelectronic Properties of Chromene‐Derived Sensitizers for Dye‐Sensitized Solar Cells

We report here computational design and theoretical study of four chromene‐derived pyrimidone appended sensitizers (M1–M4) for application in DSSC (Dye Sensitized Solar Cell). Quantum chemical calculations are performed using DFT (Density Functional Theory) and TD‐DFT (Time Dependent‐Density Functional Theory) for predicting various optoelectronic properties such as band gap, UV–vis spectra, electrostatic potential, and transition density matrices, etc. Altering the electronegativity of the atom from oxygen to sulphur in the pyrimidone ring has a significant effect, reducing the band gap by 1 eV. However, modifying the N‐H group of the pyrimidone ring to the N‐CH 3 group does not show any substantial effect. Among the four molecules, M2 and M4, with a lower energy gap of 2.5 and 2.4 eV, respectively, are more suitable for photovoltaic applications. Further, M2 and M4 exhibit high ICT (Intramolecular Charge Transfer) characteristics and strong spectral response at 410 and 425 nm, respectively. The molecular electrostatic potential (MEP) predicts charge distribution, electron injection, and the reactivity of the dye molecules. TDM graphs from electronic excitations of M1 and M3 reveal a uniform distribution of electrons throughout the molecules, while in M2 and M4, the electronic distribution is found to be more localized. Coherence can pass from one end to the other end of the molecules due to the pi electron conjugation. This research may aid in further development of pyrimidone appended chromene appended sensitizers for enhanced power conversion efficiency in DSSC devices.