Hydrogenation Effect on Hole-Transport Properties of Fullerene C70: A Density Functional Theory Study on C70H4, C70H6, and C70H8

Reorganization energies lambda of isomers of hydrogenated fullerenes, C70H (n) (n = 4, 6, 8), are investigated by the density functional theory (B3LYP/6-311G**). The smallest value of lambda (lambda (min)) of C70H4 is 74 meV and is smaller than those of C70H2 (79 meV) and C60H4 (83 meV). lambda (min) of C70H6 and C70H8 are 72 meV and 74 meV, respectively. Addition of H atoms to [6,6]-ring fusion generally gives smaller lambda than that to [5,6]-ring fusion. Hydrogenation can reduce lambda (min) of C-70 materials and the result that C70H6 has the smallest lambda (min) is same with the result of hydrogenation of C-60.