Investigation of charge carrier mobility in 5,6,11,12-tetraphenylnapthacene (rubrene) and coumarin 6 doped Alq(3) films
Journal article, 2007

The doping effect on charge carrier mobility in tris (8-hydroxyquinolinato) aluminum (Alq(3)) was studied by time-of-flight (TOF) measurements. The polar dopant, coumarin 6 (C-6) and extensive pi conjugated dopant, 5,6,11,12-tetraphenylnaphthacene (rubrene) were used for this study. The co-doped of rubrene (Rb) with C-6 into Alq3 improved the carrier mobility compared to the single doped Alq3:C-6 film. The carrier mobility in single doped Alq3:C-6 film did not follow the linear relationship of Poole-Frenkel (PF) model with applied electric field. The mobility was in agreement with the PF model at two different ranges of electric fields (F) separated by a critical field root Fc approximate to 373 (V/cm)(1/2). The mobility in co-doped Alq(3):(Rb:C-6) film followed the linear relationship with the PF model. The energetic disorder was found as similar to 0.32 eV in co-doped films. It was similar to 0.55 and similar to 0.27 eV before and after the critical field in Alq3:C-6 film. The values of positional disorders in co-doped films were estimated as similar to 1.8 and it was similar to 2 in Alq(3):C-6 film at root F <= 373 (V/cm)(1/2). The organic light emitting diode performance of the co-doped film was improved compared to single doped film. The luminescence efficiency was improved tremendously to similar to 6 Cd/A in co-doped device at 45 mA/cm(2) current compared to Alq(3):C-6 film device of similar to 1 Cd/A. (c) 2007 Elsevier Ltd. All rights reserved.

Author

C. B. Lee

Nanyang Technological University

A. Uddin

Nanyang Technological University

Thorvald Andersson

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Solid State Communications

0038-1098 (ISSN)

Vol. 142 4 206-211

Subject Categories

Physical Sciences

DOI

10.1016/j.ssc.2007.02.014

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Created

10/7/2017