NEW LUMINESCENT POLYMERS FOR LEDS AND LEGS

Statistical copolymers 5 containing poly(2-dimethyloctylsilyl-1,4-phen ylenevinylene) (DMOS-PPV) and ethoxy-5-(2'-ethylhexyloxy)-1,4-phenylen evinylene] (MEH-PPV) have been synthesized using the dehydrohalogenati on condensation route. The copolymers show a shift of photoluminescenc e maxima to longer wavelengths as the proportion of the MEH-PV unit in creases. This trend is accompanied by reduced efficiencies and lower t urn-on voltages in single layer electroluminescent devices. Light-emit ting electrochemical cells (LECs) have been prepared using a blend of DMOS-PPV 1 with poly(ethylene oxide)/lithium triflate. and the homopol ymer poly[2-methoxy-5-(triethoxymethoxy)-1,4-phenylene vinylene] (MTEM -PPV) 9 with lithium triflate. In comparison with single-layer devices which were fabricated using the homopolymers 1 and poly[2,5-bis(triet hoxymethoxy)-1,4-phenylene vinylene] (BTEM-PPV) 10, the LEC devices sh owed lower turn-on voltages.