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

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 (Delta H degrees(f)) of 222.2 kcal/mol, followed by C30Al15Y15 (Delta H degrees(f=) 891.6 kcal/mol). The relative stability of fullerenes are as follows: BN > C-60 > AIN similar to BP > AlP, indicating that the BN doping makes the C-60 more stable. The XY doping process significantly increases and decreases the solubility of C-60 fullerene in water and benzene solvents, respectively. The standard Gibbs free energy of solvation (Delta G degrees(solv)) of C-60 in water is increased from -0.7 to -33.5 kcal/mol by AIN 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 C-60, the electrical conductivity of the XY doped fullerenes are higher, and the order is as follows: AIP > BP > BN similar to AIN >> C-60. 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 0.44-0.55 eV. (C) 2017 Elsevier B.V. All rights reserved.