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Enhancing the electroluminescence properties of novel blue light emitting polymer and MEH‐PPV based white light emitting polymer devices by processing condition optimization
Author(s) -
Lee RongHo,
Hsu HsinFang
Publication year - 2007
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.26904
Subject(s) - electroluminescence , materials science , brightness , optoelectronics , polymer , spin coating , light emitting diode , quantum efficiency , thin film , layer (electronics) , optics , nanotechnology , composite material , physics
A series of triarylaminooxadiazole‐containing tetraphenylsilane light emitting polymer (PTOA) and poly(2‐methoxy, 5‐(2′‐ethyl‐hexyloxy)‐ p ‐phenylene‐vinylene) (MEH‐PPV) based white light emitting polymer devices (PLEDs) were fabricated to study blue and orange–red emitter composition and light emitting layer processing effects on white emission electroluminescence properties. Color purity, current turn‐on voltage, brightness, and current efficiency were strongly determined by MEH‐PPV content and the thin film processing condition. The intensity of PTOA blue emission was equal to that of MEH‐PPV orange–red emission when the device was fabricated by a polymer composite film containing 10 wt % of MEH‐PPV. Color purity [Commission Internationale de L'Eclairage (CIE x,y ) coordinates (0.26,0.33)] was nearly white emission under applied 8 V. The brightness and current efficiency of PTOA‐MEH‐PPV composite film based devices increased as MEH‐PPV content increased. Furthermore, white emission blue shifted with increasing spin‐rate of thin film coating and applied voltage. Low turn‐on voltage, high current density, and high brightness were obtained for the device fabricating with light emitting layer coating with high spin‐rate. Moreover, low current efficiency was obtained for the PLED with a thinner light‐emitting layer. A white emission CIE (0.28,0.34) was obtained for PTOA‐MEH‐PPV based white PLED. White PLED brightness and efficiency can be as high as 700 cd/m 2 and 0.78 cd/A, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007