We have demonstrated two general ways to increase the photoluminescence efficiency of films from conjugated polymers. One is to disperse the conjugated polymer on a molecular level by using attractive forces between the conjugated polymer and the matrix. The other method is to substitute the conjugated polymer with side chains which separates the conjugated backbones. Using this idea a new poly(thiophene) with a photoluminescence efficiency of 16% in films has been prepared. LEDs from this polymer exhibit an external efficiency of 0.1% for single layer and 0.7% for double layer diodes.
TEKNIK OCH TEKNOLOGIER (hsv//swe)
ENGINEERING AND TECHNOLOGY (hsv//eng)
light sources; polythiophene and derivatives; photoluminescence; UV-Vis-NIR absorption; nuclear magnetic resonance spectroscopy; solution processing