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Thermal properties of conduction current and carrier behavior in an organic electroluminescent device
Author(s) -
Minagawa Masahiro,
Shinbo Kazunari,
Kato Keizo,
Kaneko Futao
Publication year - 2009
Publication title -
electronics and communications in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.131
H-Index - 13
eISSN - 1942-9541
pISSN - 1942-9533
DOI - 10.1002/ecj.10048
Subject(s) - oled , electroluminescence , materials science , lithium fluoride , optoelectronics , current density , electron mobility , indium tin oxide , lithium (medication) , analytical chemistry (journal) , thin film , chemistry , nanotechnology , inorganic chemistry , organic chemistry , layer (electronics) , physics , quantum mechanics , medicine , endocrinology
Organic electroluminescent device (OLED) was fabricated using a vacuum evaporation method and thermal properties were investigated. The OLED has an indium tin oxide (ITO)/ N , N ′‐diphenyl‐ N , N ′‐bis(3‐methylphenyl)‐1,1′‐biphenyl‐4,4′‐diamine (TPD)/tris(8‐hydroxyquinoline) aluminum (Alq)/lithium fluoride (LiF)/aluminum (Al) structure. An electron‐dominant device of Al/Alq/LiF/Al structure, or a hole‐dominant device of ITO/TPD/Al structure was also fabricated in order to study the carrier behavior in the OLEDs. The current density versus voltage ( J–V ) properties with various thickness of organic layers were investigated in both electron‐ and hole‐dominant devices, and the thermal dependence of J–V properties was observed in the devices. At room temperature, conductions in a wide current region were considered to be due to space‐charge‐limited current for all of the devices. Especially for the Al/Alq/LiF/Al device and the OLED, $J \propto V^{m+1}$ relationships were observed across a wide current region. At low temperature, tunnel currents were estimated for the ITO/TPD/Al device. For the Al/Alq/LiF/Al device and the OLED, $J \infty V^{m+1}$ relationships were observed across a wide current region at low temperature. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(3): 24–31, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/ecj.10048