PHOTOLUMINESENCE AND ELECTROLUMINESCENCE OF THE BLUE EMISSION OF DEVICES BASED ON POLY(P-PHENYLENEVINYLENE) COPOLYMERS

Bright blue polymer light-emitting diodes have been fabricated by usin g the poly(p-phenylenevinylene)-based copolymers with 10 C long alipha tic chains as the electroluminescent layers, PBD in PMMA and Alq(3) as the electron-transporting layers, and aluminum as the cathode. The mu ltilayer structure devices show 190 cd/m(2) light-emitting brightness at 460 nm, 15 V turn-on vol- tage. It is found that the intensities of photoluminescence and electroluminescence (EL) increase with increasi ng aliphatic chain length, the EL intensity and operation stability of these polymer light-emitting diodes can be improved by reasonable des ign of the structure.