[The effect of side chain structure on the excitation transfer and charge transfer processes in PPV/C60 composite system].

In this paper, we investigated the effect of side chains on the optical properties of PPV derivatives, the excitation transfer and charge transfer process in the PPV/C60 composite films. The results demonstrate that the absorption and PL emission bands of PPV shift towards lower photon energy with increasing of the length of PPV side chain, which indicates that energy gap of PPV derivatives become narrow with their side chain length increasing. In the PPV/C60 composite films, the emission of PPV derivatives was greatly quenched due to the efficient excitation transfer process between PPV and C60. We observed the absorption band of C60- located at 920 nm in the MD-PPV/C60 composite films, which reveals the existence of charge transfer process in the ground state of the composite films. This results show that the side chains of PPV derivatives not only influence the properties of absorbance and photoluminescence but also influence the electronic affinity of PPV polymers, which means that both physical and chemical properties of PPV can be monitored by controlling its side chain structure.