End-capped engineering of bipolar diketopyrrolopyrrole based small electron acceptor molecules for high performance organic solar cells

Abstract

Non-fullerene small acceptor molecules demonstrate promising photovoltaic properties supported the progress of organic solar cells (OSCs). In organic photovoltaics, non-fullerene small acceptor compounds are valuable than traditional fullerene-based acceptor molecules for their good contribution in organic solar cells. This research generally focusses on Bipolar Diketopyrrolopyrrole (F(DPP)2B2) based small electron acceptor compounds used for organic solar cells (OSCs). For this purpose, four newly developed A-D-A (Acceptor-Donor –Acceptor) type electron accepting compounds named as V1, V2, V3, and V4 are planned for organic solar cells to study their optoelectronic characteristics. MPW1PW91/6-31G(d,p) basis set was used for calculations of various geometric parameters. Among all these, newly designed molecules V1 is proven an appropriate compound for OSCs applications due to the photovoltaic characteristics like low band gap between HOMO and LUMO (1. 88 eV) and V3 molecule shows broader absorption λmax in the gas phase (741.62 nm) and chloroform solvent (785.95 nm). Molecule V2 exhibits the lowest value of mobility of electrons (0.0806 Eh). All the designed compounds exhibit better open-circuit voltage, fewer energies of excitations, the highest value of absorption, greater dipole moment, equivalent binding energies, well-organized transport of electron and hole as compared to reference R. Thus, these molecules are suggested to researchers for the future development of highly efficient OSCs.