Fluorination and chlorination effects on the charge transport properties of the IDIC non-fullerene acceptor: an ab-initio investigation

Fused-ring electron acceptors end-capped with withdrawing groups have contributed to the ever-increasing power conversion efficiency of organic solar cells. Adding π-extensions and halogenating end are two popular strategies boost performance even further. In this work, a typical non-fullerene acceptor molecule, IDIC, is used as model system for investigating impact halogenation approach at molecular level. The substituted by fluorinated chlorinated counterparts their electronic optical properties systematically probed using ab-initio calculations. gas phase, lowers HOMO LUMO energy levels narrows gap, especially compound. Moreover, IDIC exhibits largest redshift smallest reorganization energy. Finally, crystal structures three compounds constructed, revealing an improved transfer integral rate halogenated variants. Specifically, chlorination strategy leads increase 60% in rate, compared halogen-free IDIC.