Physical properties and elemental composition of starlike fullerene-containing polystyrene films

The elemental composition of starlike fullerene-containing polystyrene films has been determined by the Rutherford backscattering, ion x-ray spectrum analysis, and nuclear reaction method. The physical properties of the films are investigated by ellipsometric, photoluminescence, and dc electrical conductivity techniques. The complex refractive index of the films is equal to 1.7−i(0.05−0.10). It is found that a maximum in the photoluminescence spectrum of the fullerene-containing polystyrene film is shifted toward the high-energy range as compared to that of the C60 film. The energy shift is directly proportional to the number N of polymer chains chemically bonded to the fullerene molecule and can be described by the empirical formula ΔE [eV]=0.04N. The electrical conductivity of the films increases proportionally with the molar concentration of C60.