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このアイテムの引用には次の識別子を使用してください:
http://hdl.handle.net/10119/10282
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タイトル: | Optical, morphological, structural, electrical, molecular orientation, and electroluminescence characteristics of organic semiconductor films prepared at various deposition rates |
著者: | Matsushima, Toshinori Shiomura, Koutaro Naka, Shigeki Murata, Hideyuki |
キーワード: | Organic light-emitting diode High deposition rate Photoluminescence quantum yield and lifetime Time-of-flight charge carrier mobility Molecular orientation |
発行日: | 2011-10-01 |
出版者: | Elsevier |
誌名: | Thin Solid Films |
巻: | 520 |
号: | 6 |
開始ページ: | 2283 |
終了ページ: | 2288 |
DOI: | 10.1016/j.tsf.2011.09.060 |
抄録: | Extremely high deposition rates of ≈7200 nm s^<-1> for N,N´-diphenyl-N,N´-bis(1-naphthyl)-1,1´-biphenyl-4,4´-diamine (a-NPD) and of ≈1700 nm s^<-1> for tris(8-hydroxyquinoline)aluminum (Alq_3) are found to be possible by controlling source-substrate distances and crucible temperatures. Shapes of ultraviolet-visible absorption spectra and photoluminescence (PL) spectra, atomic force microscope images, X-ray diffraction patterns, PL quantum yields, PL lifetimes, and PL radiative decay rates of the films remain independent of the deposition rates ranging from 0.01 to 1000 nm s^<-1>. On the other hands, hole currents of hole-only α-NPD devices increase ≈3 times while electron currents of electron-only Alq_3 devices decrease by ≈1/60 as the deposition rates are increased from 0.01 to 10 nm s^<-1>. The increase in hole current is confirmed to arise from an increase in hole mobility of α-NPD measured using a time-of-flight technique. The increase in hole moility is probably due to a parallel orientation of an electronic transition moment of α-NPD at the higher deposition rates. Moreover, the three orders of magnitude increase in deposition rate from 0.01 to 10 nm s^<-1> of α-NPD and Alq_3 results in a relatively small increase in voltage of ≈15% and a decrease in external quantum efficiency of ≈30% in organic light-emitting diodes (OLEDs). The reduction of the OLED performance is attributable to the marked decrease in electron current relative to the slight increase in hole current, indicating a decrease in charge balance factor at the higher deposition rates. |
Rights: | NOTICE: This is the author's version of a work accepted for publication by Elsevier. Toshinori Matsushima, Koutaro Shiomura, Shigeki Naka, Hideyuki Murata, Thin Solid Films, 520(6), 2011, 2283-2288, http://dx.doi.org/10.1016/j.tsf.2011.09.060 |
URI: | http://hdl.handle.net/10119/10282 |
資料タイプ: | author |
出現コレクション: | c10-1. 雑誌掲載論文 (Journal Articles)
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