Photoluminescence and electroluminescence properties of coumarin-urea/poly(N-vinylcarbazole) blends

The photoluminescence (PL) properties of a novel coumarin derivative (DCDU) in solution state and in poly(N-vinylcarbazole) (PVK) matrix were investig ated. The single-layer electroluminescence (EL) devices fabricated from the DCDU/PVK blends showed the emission peak varying from 445 nm to 472 nm wit h the different dye doping ratio. When 2,5-bis(5'-tert-butyl-2-benzoxazoly) thiophene(BBOT) was used as an electron transport layer, the ITO/(2 wt.% DC DU+ PVK)/BBOT/Al device displayed the improved characteristics with the low turn-on voltage at 6.3 V, a maximum luminance of 730 cd/m(2) and an extern al quantum efficiency of 0.8%. (C) 1999 Elsevier Science S.A. All rights re served.