INFRARED-SPECTRA AND PHOTOINDUCED ABSORPTION OF C-60 DOPED POLYHEXYLTHIOPHENE

We report the IR spectra and the photoinduced absorption of polyhexylthiophene(PHT) doped with C-60. The presence of C-60-(n) anions is observed in the IR spectra by a mode at 1383 cm(-1) and a broad electronic transition at 1.2 eV, while most of the C-60 molecules stay neutral. This is indicative that for a small fraction of C-60 molecules, charge transfer occurs in the ground state. The photoinduced absorption spectra display a sharp transition at 1.15 eV peculiar to C-60 monoanion, the spectral features change with fullerene concentration. The intensity of the polymer photoinduced bands increases 5-10 times due to photoinduced charge transfer to C-60