Exciton binding energies in biphenyl derivatives with ferrocenyl and fluorine-containing germyl substituents

To increase the efficiency of organic photovoltaic devices, it is necessary to search for new promising compounds that provide efficient charge separation during absorption in the optical region of the spectrum. As such compounds, biphenyl derivatives with ferrocenyl and fluorine-containing germyl substituents have been studied in the present work. The DFT and TD-DFT methods (B3LYP, CAM-B3LYP, PBE0, wB97XD) have been used to study the structures and energies of excited states of these derivates and to estimate the exciton binding energies in materials based on them in vacuum and condensed matter. For a number of compounds, the obtained exciton binding energies are close to zero, and in a separate case even less than zero, which demonstrates the prospect of their synthesis and use.