Unraveling the substituent impact of fluorinated & oxidized sumanene derivatives on stacking interactions and charge transport

Abstract

The substituent effects of fluorinated and oxidized sumanene derivatives on their geometric structures, frontier molecular orbitals, intermolecular interactions, reorganization energies, transfer integrals, radiation and non-radiation decay rates have been systematically investigated using density functional theory (DFT). Analysis of the interaction energies of the dimers reveals that significant D/R values (dispersion to repulsion interaction ratio), besides the total interaction energies and electrostatic interactions, are essential to explain the one-dimensional perpendicular columnar stacking structures in the crystals of these sumanene derivatives. Our findings suggest that benzyl-oxidized sumanene derivatives are more advantageous for electron transport than their phenyl-substituted counterparts, exhibiting higher charge-transfer integral values in staggered conformations compared to eclipsed ones. Notably, these sumanene derivatives hold promise as novel electron transport materials rather than fluorescence emission, particularly 1,4,7-trioxosumanene with a staggered conformation in the crystal structure. Overall, this work provides valuable theoretical insights for the design of organic semiconductor materials based on sumanene derivatives.