Deciphering the role of end-capped acceptor units for amplifying the photovoltaic properties of donor materials for high-performance organic solar cell applications

Abstract

Non-fullerene organic solar cells (OSCs) deliver the highest efficiency gains overall in reported literature. Efforts are being made to refine efficacies and stabilities of organic solar cells through the designing of acceptor molecules that contain powerful electron-withdrawing groups. Here, we computed four acceptors (Y1-Y4) by end-capped alterations on reference R and optimize photophysical, optoelectronic and photovoltaic properties. Therefore, certain properties such as orientation of FMO’s, excitation and binding energy, open-circuit voltage (Voc), transition density matrix and reorganizational energy of hole and electron are observed in comparison with reference. The calculated molecular structures of Y1 and Y4 show a high red-shift, while that of Y2 and Y3 display slightly blue-shift, along with very fine excitation energies and high charge mobilities. All these molecules (Y1-Y4) and the reference R presents band-gaps as small as 1.5–2.5 eV, and considerable charge transfer potential. This theoretical system shows that end-capped acceptors alteration is quite remarkable to establish desired optoelectronic properties. Thus, Y1-Y4 are suggested to researchers aiming at the potential commercialization of highly efficient solar cells systems.