Structural modification on Dimethoxythienothiophene based non-fullerene acceptor molecule for construction of high-performance organic chromophores by employing DFT approach

Abstract

In this work, with the directive of increasing the power conversion efficiency of organic solar cells, seven new acceptor molecules (N1–N7) have been designed by the end-group modification of A-D-A type reference molecule TTDTC-4F (R). Density functional theory (DFT) based computational methodologies were applied to these structures to calculate different parameters like their planarity, bandgaps, maximum absorption wavelengths, excitation energies, oscillator strengths, light-harvesting efficiencies, electron and hole reorganization energies, binding energies, dipole moments, open-circuit voltage (Voc), and fill factors (FF), etc. All the devised structures showed better results in terms of their shorter bandgaps, redshift in absorption, lower excitation and binding energies, along with reduced reorganization energies, which emphasizes their better charge transfer properties with respect to R. Furthermore, they also demonstrated good values of dipole moment and light-harvesting efficiencies (LHE). Higher LHE values of designed molecules pointed towards their better abilities to harvest light in order to produce charge carriers. But in terms of open-circuit voltage (Voc) and fill factor (FF), N2 and N5 showed higher, while N7 showed the highest result when compared to R. So, these developed molecules could be the best choice for utilization in the active layer of organic solar cells (OSCs).