Comparative study of lower fullerenes doped with boron and nitrogen

This work is aimed at comparing the relative stabilities of lower fullerenes Cn (40≤n≤50) doped with boron and nitrogen. Semi-empirical geometry optimizations and ab initio electronic structure calculations on pure and substituted fullerenes are presented. Nitrogen doping substantially decreases the formation enthalpy of all molecular cages when the dopant occupies pentagonal sites. Boron adopts a more planar geometry and is preferentially substituted in hexagonal sites, being less efficient in stabilizing the curved fullerene structures. The electronic structures of C50 isomers substituted by nitrogen and boron are shown to form donor/acceptor pairs for use in molecular rectification.