Photoluminescence of poly(1,4-phenylenevinylene) derivatives in solution and film

Abstract

Four dialkoxy-substituted poly(1,4-phenylenevinylene) (PPVs) and four copolymers of poly[(2-methoxy-5-(2′-ethylhexloxy)-p-phenylene vinylene)] (MEH-PPV) and non-substituted PPV were synthesized. The comparative photoluminescence properties of the resulting polymers are reported. In dilute solution the length of side chains plays an important role in the emission of PPVs, but the morphology of the films has an important effect on the photoluminescence. As for the four copolymers, the absorption and emission spectra were blue shifted and the fluorescence quantum efficiency improved with the increase of the non-substituted PPV content. These copolymers possess both the good solubility of MEH-PPV and the high fluorescence efficiency of PPV. Additionally, the chemical structures of these copolymers can be controlled. The emission of the copolymer films changed with the thickness of the films, which may be caused by the interaction between the two different chains of MEH-PPV and PPV on the copolymer backbone. The most important is that a laser-like emission was observed from MEH-PPV neat film, which suggested that PPVs would be very promising laser materials. Copyright © 1999 John Wiley & Sons, Ltd.