Open AccessElectroluminescent Devices Using a Polymer of Regulated Conjugation Length and a Polymer Blend
Author(s) -
Zyung Taehyoung,
Jung SangDon
Publication year - 1996
Publication title -
etri journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 46
eISSN - 2233-7326
pISSN - 1225-6463
DOI - 10.4218/etrij.96.0196.0036
Subject(s) - electroluminescence , materials science , optoelectronics , quantum efficiency , polymer , band gap , photoluminescence , light emitting diode , diode , exciton , polymer blend , nanotechnology , composite material , physics , condensed matter physics , copolymer , layer (electronics)
A blue light emitting device has been successfully fabricated using a polymer with regulated conjugation length containing trimethylsilyl substituted phenylenevinylene units. Electroluminescence from the device has an emission maximum at 470 nm. The device shows typical diode characteristics with operating voltage of 20 V and the light becomes visible at a current density of less than 0.5 mA/cm 2 . The electroluminescence spectrum is virtually identical with the photoluminescence spectrum, indicating that the radiation mechanisms are the same for both. A light emitting device using the blend of a large band gap polymer and a small band gap polymer was also fabricated. Light emission from the small band gap polymer shows much improved quantum efficiency, but there is no light emission from the large band gap polymer. Quantum efficiency of the blend increases up to about two orders of magnitude greater than that of the small band gap polymer with increasing proportion of the large band gap polymer. The improvement in quantum efficiency is interpreted in terms of exciton transfer and the hole blocking behaviour of the large band gap polymer. Finally, we have fabricated a patterned flexible light emitting device using the high quantum efficiency polymer blend system.