Computational Study on the Photovoltaic Properties of Thiazole-Based Acceptors in Fullerene-Free Organic Solar Cells: A Theoretical Approach

A promising approach to enhance the power conversion efficiency of organic solar cells (OSCs) is end-capped group reconfiguration. Five distinct acceptor molecules were produced by end-group modification of the recently synthesized chemical DC-IDT2Tz (R). Density functional theory (DFT) and time-dependent DFT were utilised for computing an array of geometric and photovoltaic features of formulated and reference molecules, consisting of charge transfer analysis, the energy of excitation, absorption maximum, binding energy, oscillator strength, frontier molecular orbital analysis, and transition density matrix analysis. The absorption spectra of newly designed compounds exhibited a narrow energy band gap (Eg) with red-shifting. Engineered chemicals additionally demonstrate lower binding and excitation energies. A comprehensive investigation is conducted as well to assess the charge transfer between the acceptor and donor parts. The aforementioned investigations indicated that the discovered chemicals possess intriguing potential for optimized organic solar cell implementation. The modification of terminal structures has been revealed to be effective in modifying the energy levels of frontier molecular orbitals, band gap, absorption spectra, reorganization energy, open-circuit voltage, and binding energy values in the inspected molecules. In light of the above results, these compounds show potential as acceptor materials.