In silico modelling of acceptor materials by End-capped and π-linker modifications for High-Performance organic solar Cells: Estimated PCE > 18%

Abstract

Efficient acceptor materials are of great importance in improving the performance of organic solar cells. Electron transport materials play a crucial role in improving the power conversion efficiency (PCE) of photovoltaic devices. In recent years, great efforts have been made to develop new acceptor materials that can be used in organic solar cells (OSCs). Previous reports have shown the high efficiency of CH1007 as an acceptor material in OSCs application. In this study, we used CH1007 as a reference molecule (R) and developed four new acceptor materials (CF1-CF4) derived from CH1007 based on the tuning of the end-capped and π-linker units within the conjugated framework. Density functional theory calculations (DFT) were performed to determine the structural, optoelectronic, and charge transfer properties of the developed materials. CF1-CF4 exhibited narrow band gaps with a redshift of the absorption maxima compared to R, which will lead to an improvement in the PCE of OSC. Low reorganization energies of holes and electrons were determined for the designed molecules compared to the reference molecule, indicating high charge carrier transport within these molecules. Transition density matrix (TDM) analysis revealed the movement of electron density from the core block to the acceptor moieties via π-linkages. The photovoltaic parameters were investigated and we found a relevant open-circuit voltage (Voc) for the designed molecules. A mixing study was performed for PTB7-Th: CF3, which gave interesting results. Based on the founding results and comparison with R, we found that the designed molecules are promising materials that can be used as acceptors for high-efficiency OSCs.