Organic electroluminescent devices using europium complex‐doped poly(N‐vinylcarbazole)

Abstract

Electroluminescence (EL) properties of europium (Eu) complex‐doped poly(N‐vinylcarbazole) (PVK) were investigated. A device structure of glass substrate/indium‐tin oxide/hole‐injection layer/Eu complex‐doped PVK/hole‐blocking layer/electron transport layer/electron‐injection layer/Al was employed. Red emission originating from Eu complex was observed. Relatively high luminance of 50 cd/m2 and an efficiency of 0.2% were obtained. Copyright © 2004 John Wiley & Sons, Ltd.

Efficient monochromatic red-light-emitting PLEDs based on a series of nonconjugated Eu-polymers containing a neutral terpyridyl ligand

“…6 To date, a number of organic Eu-complex luminescent materials have been extensively studied as one kind of the most important red-emitting materials in organic light-emitting diodes (OLEDs) because of their pure red monochromic characteristic emission with FWHM of 5-10 nm, high photoluminescent (PL) efficiency, chemical environment stability and theoretical internal quantum efficiency approaching 100%. 7 To further improve the EL efficiencies of Eu-complexes, many bright and efficient electroluminescent devices based on small molecular Eu-complexes are achieved through doping/ blending, in which 4,4 0 -N,N 0 -dicarbazolebiphenyl (CBP), 8 2-biphenyl-4-yl-5-(4-tert-butyl-phenyl)-1,3,4-oxadiazole (PBD), 9 and polyvinylcarbazole (PVK) 10 with high triplet excited energy levels are oen used as the hosts. Though such doped devices have the advantage of allowing the fabrication of thin lms by spin-coating, blending and doping of Eu-complexes in matrices, they have a tendency to show phase separation over time, leading to instability in the device's performance.…”

Exciton quenching in emitter blends for organic light emitting devices probed by electric field–dependent time-resolved luminescence

“…Thus, attempts to explain high field emission characteristics of organic LEDs basing on one of them only would fail or present a crude approximation at most of complex processes underlying their function. [1][2][3][14][15][16] In these emitters both PL and EL, originate from 5 D 0 → 7 F n ͑n =0,1, ... ,6͒ transitions of the Eu 3+ ion, its excited states being populated by the energy transfer from excited organic ligands. [8][9][10] The measurement of PL quenching at low excitation intensities in films sandwiched between two electrodes allowing the application of external voltage would provide the missing link in order to disentangle bimolecular exciton-exciton interactions and electric field effects on exciton behavior.…”

Modulation in Electric Conduction of PVK and Ferrocene-Doped PVK Thin Films

“…The PVK has outstanding physicochemical properties such as high refractive index, photo-refractive, photoconductive, etc. Thus, PVK-based materials are applicable for several applications (e.g., photovoltaic cell and holograms photocopies) [5][6][7]. It was also reported that the nanocomposites consisting of inorganic nanoparticles and organic polymers (PVK) often exhibit far superior properties (mechanical, electrical, optical, and magnetic) than that of PVK [8,9].…”