H. Murata et al., A NOVEL FABRICATION TECHNIQUE AND NEW CONJUGATED POLYMERS FOR MULTILAYER POLYMER LIGHT-EMITTING-DIODES, Polymers for advanced technologies, 8(7), 1997, pp. 459-464
We report a novel fabrication technique for multilayer light-emitting
diodes composed of new polyoxadiazole, POD, conjugated polymers for th
e first time. The fabrication technique called vapor deposition polyme
rization is described. Chemical modification of monomers brought about
the enhancement of reactivity and the production of high molecular we
ight of POD. Emission color with photoexcitation was controllable from
violet-blue to green by varying the chemical structures of PODs. It w
as found that PODs could be employed as either electroluminescent or c
arrier-injecting layers by the optimization of the device structure. T
wo types of bilayer devices, which are constructed with POD/tris (8-qu
inolinoato) aluminum, Alq(3), and with two POD layers with different c
hemical structures, were investigated. Carrier injection begins in the
POD/Alq(3), bilayer device near 7 V, and the device emitted green lig
ht from Alq(3),. The maximum luminance of the POD/Alq(3), device reach
ed 3500 cd/m(2). The POD/POD bilayer device emitted blue light with ma
ximum luminance of 21 cd/m(2). Electroluminescence spectra of the devi
ces coincided with photoluminescence spectra of each emitting material
used. (C) 1997 by John Wiley & Sons, Ltd.