PHOTOLUMINESCENCE STUDIES ON POLY(1,4-PHENYLENE 1'-PHENYL VINYLENE) DOPED WITH FLUORENYLIDENE MALONONITRILE

The results of steady-state and transient photoluminescence (PL) studi es on poly(1,4-phenylene 1'-phenyl vinylene) (PPV-P) thin films doped with an electron acceptor, fluorenylidene malononitrile (BCFM), are pr esented. The steady-state PL of undoped PPV-P is characterized by a br oad band with a maximum at 505 nm and a fairly long tail extended to t he near-infrared. The main PL band, peaked at 505 nm (A band), was str ongly quenched by BCFM, while the intensity of the far-red PL emission tail (B band) was not affected by BCFM. By contrast the lifetime of t he B band increased with BCFM doping. A photoinduced electron transfer , followed by charge separation, is proposed as the mechanism for the observed PL quenching, The observed long-lived red PL emission is asso ciated with exciplex formation.