Theoretical modelling of novel indandione-based donor molecules for organic solar cell applications

The development of efficient hole transport materials (HTMs) are highly attractive for the photovoltaic community to further improve the power conversion efficiency (PCE) and stability of organic solar cells. Therefore, in the present study, we have designed six new (H3T1-H3T6) small-molecule based HTMs for bulk-heterojunction (BHJ)-OSC. The photophysical characteristics and optoelectronic characterizations are systematically investigated. Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) are employed to study the arrangement of frontier molecular orbitals (FMOs), optical characteristics, open-circuit voltages, density of states, transition density matrix, and reorganization energies of holes and electrons. The designed materials (H3T1-H3T6) have shown a better absorption phenomenon that ranges maximum up to ∼563.00 nm and offering optical band gap at ∼2.10 eV. Additionally, all the designed materials have displayed a well-matched HOMO along with higher LUMO energy levels regarding PC₆₁BM molecule. The calculations of H3T-2/PC₆₁BM provide a deep insight about the charge shifting at the donor-acceptor (D-A) interface. The results of these theoretical characterizations have shown that an efficient molecular designing and strategy are prerequisite to get a desirable photovoltaic precursor best fitted for BHJ-OSCs. Thus, these modelled materials (H3T1-H3T6) are being suggested for synthesis and future development of efficient organic solar cell devices.