A computational investigation of spin filtering behavior in all-organic radicals

All-organic radicals have been identified as a class of molecules which can have either excellent spin filter efficiency or exceptional conductance, with the ability to switch between the two regimes by applying bias voltage. However, this remarkable behavior was only identified for phenalenyl (PLY)-based radicals with thiol (-SH) anchoring groups. Changing anchoring groups, to methyl-sulfur (-SMe) or dihydrobenzothiophene (-BT), may affect the previously identified properties. We calculate bias-dependent charge transport across a variety of heteroatom substituted PLY radicals as well as the closed-shell molecule, naphthalene with -SH, -SMe and -BT anchoring groups using the non-equilibrium Green’s function technique in conjunction with density functional theory (NEGF-DFT). Our simulations highlight the importance that anchoring groups play in the role of charge transport across molecular devices, and touch on the interplay of design principles, electronic conductance, and spin filtering.