A theoretical study on the C30X15Y15 (X = B, and Al; Y = N, and P) heterofullerenes

Abstract

Using density functional theory calculations, we investigated the stability, solubility, structural, electronic, and optical properties of C30X15Y15 (X=B, and Al; Y=N, and P) heterofullerenes. The C30B15N15 is found to be the most stable heterofullerene with standard formation enthalpy (ΔH°f) of 222.2kcal/mol, followed by C30Al15N15 (ΔH°f=891.6kcal/mol). The relative stability of fullerenes are as follows: BN>C60>AlN∼BP>AlP, indicating that the BN doping makes the C60 more stable. The XY doping process significantly increases and decreases the solubility of C60 fullerene in water and benzene solvents, respectively. The standard Gibbs free energy of solvation (ΔG°solv) of C60 in water is increased from −0.7 to −33.5kcal/mol by AlN doping process. The dopant X atoms are mainly contributed in generation of occupied states but the Y ones largely create the virtual states. Compared to the pristine C60, the electrical conductivity of the XY doped fullerenes are higher, and the order is as follows: AlP>BP>BN∼AlN>>C60. This indicates that the Al atoms destabilize and P ones stabilize the HOMO and LUMO levels, respectively. The optical gap of these fullerenes is smaller than the HOMO-LUMO gap by about 0.44–0.55eV.