Mechanisms of injection enhancement in organic light-emitting diodes through an Al/LiF electrode

被引:195
作者
Heil, H [1 ]
Steiger, J
Karg, S
Gastel, M
Ortner, H
von Seggern, H
Stössel, M
机构
[1] Tech Univ Darmstadt, Inst Mat Sci, Darmstadt, Germany
[2] Siemens AG, Corp Technol, D-8520 Erlangen, Germany
关键词
D O I
10.1063/1.1331651
中图分类号
O59 [应用物理学];
学科分类号
摘要
The mechanisms of enhanced electron injection into the electron transport layer of Alq(3) [tris(8-hydroxyquinoline)-aluminum] via LiF interlayers are studied by means of I-V characteristics, secondary ion mass spectroscopy (SIMS), and Kelvin probe measurements. Devices for single carrier injection were prepared using aluminum electrodes, Alq(3) electron transport layers, and thin intermediate layers of LiF. It was found that devices deposited in the order Alq(3)-LiF-aluminum have a much higher electron injection capability than structures deposited in the order aluminum-LiF-Alq(3). SIMS depth profile analysis reveals that the evaporation of Al on LiF leads to a spatial separation of Li and F probably induced by a chemical reaction of Al with LiF. Simple thermodynamic calculations support the energetic feasibility of such a reaction. Titanium cathodes in the same layer sequence also exhibit electron injection enhancement, probably due to their similar chemical reactivity. However, electron injection from Ag electrodes is not significantly improved by the introduction of a LiF interlayer. (C) 2001 American Institute of Physics.
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收藏
页码:420 / 424
页数:5
相关论文
共 12 条
[1]   Enhanced electron injection in organic electroluminescence devices using an Al/LiF electrode [J].
Hung, LS ;
Tang, CW ;
Mason, MG .
APPLIED PHYSICS LETTERS, 1997, 70 (02) :152-154
[2]  
Ishii H, 1999, ADV MATER, V11, P605, DOI 10.1002/(SICI)1521-4095(199906)11:8<605::AID-ADMA605>3.0.CO
[3]  
2-Q
[4]   Highly efficient and bright organic electroluminescent devices with an aluminum cathode [J].
Jabbour, GE ;
Kawabe, Y ;
Shaheen, SE ;
Wang, JF ;
Morrell, MM ;
Kippelen, B ;
Peyghambarian, N .
APPLIED PHYSICS LETTERS, 1997, 71 (13) :1762-1764
[5]   Bright organic electroluminescent devices having a metal-doped electron-injecting layer [J].
Kido, J ;
Matsumoto, T .
APPLIED PHYSICS LETTERS, 1998, 73 (20) :2866-2868
[6]   Fabrication and electroluminescence of double-layered organic light-emitting diodes with the Al2O3/Al cathode [J].
Li, F ;
Tang, H ;
Anderegg, J ;
Shinar, J .
APPLIED PHYSICS LETTERS, 1997, 70 (10) :1233-1235
[7]   XPS and UPS study of charge transport material electrode interface of light emitting diodes. [J].
Osada, T ;
Barta, P ;
Johansson, N ;
Kugler, T ;
Bröms, P ;
Salaneck, WR .
SYNTHETIC METALS, 1999, 102 (1-3) :1103-1104
[8]   Photoemission spectroscopy investigation of magnesium-Alq3 interfaces [J].
Rajagopal, A ;
Kahn, A .
JOURNAL OF APPLIED PHYSICS, 1998, 84 (01) :355-358
[9]   Organic-inorganic multilayer structures: a novel route to highly efficient organic light-emitting diodes [J].
Riess, W ;
Riel, H ;
Seidler, PF ;
Vestweber, H .
SYNTHETIC METALS, 1999, 99 (03) :213-218
[10]   Photoemission spectroscopy of LiF coated Al and Pt electrodes [J].
Schlaf, R ;
Parkinson, BA ;
Lee, PA ;
Nebesny, KW ;
Jabbour, G ;
Kippelen, B ;
Peyghambarian, N ;
Armstrong, NR .
JOURNAL OF APPLIED PHYSICS, 1998, 84 (12) :6729-6736