EFFICIENT BLUE LUMINESCENCE OF A CONJUGATED POLYMER EXCIPLEX

Efficient blue light emission is observed from a bilayer thin film of poly(p-phenylene-2,6-benzobis(oxazole)) (PBO) and tris(p-tolyl)amine ( TTA) dispersed in the matrix of Bisphenol A polycarbonate. PBO thin fi lms emit green light with the emission peak at 500 nm. The luminescenc e of PBO/TTA bilayer thin films (15-50 nm) has a peak at 474 nm and a factor of 3.4-4.2 increase in fluorescence quantum efficiency relative to PBO thin films. The steady state and time-resolved photoluminescen ce results suggest that the emission from PBO/TTA bilayer films origin ates from (PBO-TTA(+)) exciplex formation due to photoinduced electro n transfer. The present results demonstrate that conjugated polymer ex ciplexes represent a new approach to blue luminescence as well as a me ans to enhance the solid state fluorescence quantum efficiency of conj ugated polymers.