Blue electroluminescence from novel silicon-based copolymers at low operating voltages

Novel silicon-based copolymers exhibit the ground-state absorption band maxima around 340 similar to 390 nm and their photoluminescence in blue region. The blue light-emitting diodes (LED) fabricated with the copolymers could be successfully operated at the considerable low voltages compared to those for other blocked PPV copolymers. The introduction of both silicon and carbazole moieties into PPV main chain results in an interesting dependencies of EL spectral feature on the operating voltage for LED. In order to know the origin of the dependence, we have investigated PL and its excitation spectra of the silicon based copolymeric systems.