Can Single-Atom Change Affect Electron Transport Properties of Molecular Nanostructures such as C₆₀ Fullerene?

At the nanoscale, even a single atom change in the structure can noticeably alter the properties, and therefore, the application space of materials. We examine this critical behavior of nanomaterials using fullerene as a model structure by a first-principles density functional theory method coupled with nonequilibrium Green’s function formalism. Two different configurations, namely, (i) endohedral (B@C₆₀ and N@C₆₀), in which the doping atom is encapsulated inside the fullerene cage, and (ii) substitutional (BC₅₉ and NC₅₉), in which the doping atom replaces a C atom on the fullerene cage, are considered. The calculated results reveal that the conductivity for the doped fullerene is higher than that of the pristine fullerene. In the low-bias regime, the current (I) voltage (V) characteristic of the endohedral as well as the substitutional configurations are very similar. However, as the external bias increases beyond 1.0 V, the substitutional BC₅₉ fullerene exhibits a considerably higher magnitude of current than all other species considered, thus suggesting that it can be an effective semiconductor in p-type devices.