On the difference in electronic properties between fullerene and

Electronic properties of fullerene C 60 and its derivatives C 60 X 2 , where X = H, C 4 H 9 , ( C H 2 ) n COOH ( n = 3 , 5 , 7 ) , and C 4 H 8 SH, are investigated by the density functional theory (B3LYP/6-31+G∗) aiming at efficient design of new organic semiconductors. Concerning electron-injection and electron-transport properties of the materials, LUMO energy, adiabatic electron affinity, and reorganization energy are discussed. The electronic properties of C 60 X 2 are considerably different from those of C 60 . They are determined by the addition position of X and not by the chemical nature of X . Generally, C 60 X 2 is predicted to be superior to C 60 in the electron-injection property but to be inferior in the electron-transport property.