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Abstract: The absorption spectra and the photovoltaic effect in thin films consisting of a blend of p-type poly(3-hexylthiophene) and n-type acceptor [6,6]-phenyl C60 butyric acid methyl ester have been studied and a decrease in inter-band absorption in the wavelength range of 450–600nm is observed. This absorption quenching is attributed to the disordering of the poly(3-hexylthiophene) chains and a charge transfer between poly(3-hexylthiophene) and [6,6]-phenyl C60 butyric acid methyl ester, as evidenced by FTIR and X-ray photoelectron spectra. Finally, photovoltaic cells were fabricated utilizing the blend as the active layer and the device characteristics were studied. [Copyright &y& Elsevier]

The microscopic model used previously for interpreting the low-energy electro-absorption (EA) spectrum of the fullerene crystal is applied to reproduce theoretically the corresponding signal at 4.5 eV. It is demonstrated that the spectral feature observed at that energy, in spite of its shape resembling that located at 3.7 eV and attributed to CT excitons, is in fact due to a Frenkel state. [Copyright &y& Elsevier]