earticle

영어

Organic electroluminescent devices are light-emitting diodes in which the active materials consist entirely of organic materials. Recently, many fluorescent organic materials have been reported and the study on synthesis and application of new organic light-emitting materials has been demanded. This paper reports the optical and electrical characteristics of OLEDs using novel polymers containing biphenyl structure. First, Optical properties of novel light-emitting biphenyl derivatives doped with poly(9-vinyl carbazole)(PVK) and emitted blue, bluish green color, which is attributed to the overlap area between PL spectrum of host(PVK) and absorption spectra of guests(polymer). This is correspondent with Forster energy transfer process in the blends. And, OLED devices were fabricated using poly (3,4-ethylenedioxy thiophene) (PEDOT) as a hole injection material and tris-(8-hydroxyquinoline) aluminum (Alq3) as an electron transporting material. EL devices fabricated as ITO/PEDOT/PVK doped with biphenyl derivatives/Alq3/Li:Al and I-V-L chatacteristics and emitting efficiency of EL devices were examined. Finally, the drift mobility of PVK doped with biphenyl derivatives and Alq3 were measured by TOF technique varying applied electric field. EL efficiency was increased as the ratio of hole mobility of PVK doped with biphenyl derivatives and electron mobility of was close to one.