以熱蒸鍍及水溶液轉印製程研究有機發光二極體之電子傳輸層

The Study of Electron Transport Layers in Organic Light-Emitting Diodes by Thermal Evaporation and Stamping in Solution Processes

艾比西(Apisit Chittawanij)

指導教授 ： 莊賦祥

共同指導教授 ： 蔡裕勝

國立虎尾科技大學/電機資訊學院/光電工程系光電與材料科技博士班/博士(2015年)

https://doi.org/10.6827/NFU.2015.00163

摘要

有機發光二極體(OLEDs)在螢幕中的應用正在被商業化而且在不久的將來OLEDs會用於照明上。將OLEDs用於照明上有望獲得低功耗和低成本，以便與日光燈管和無機LEDs等光源競爭。本論文討論了高性能OLEDs的設計，包括通過熱蒸鍍和水溶液轉印製程研究電子傳輸層。本論文包含如下的研究工作： (i) 開發了一個在混合白光OLEDs中摻雜了2-(hydroxyl) quinolone lithium (Liq) 的tris(8-hydroxy-quinolinato)aluminium (Alq3) n-型摻雜系統並將其裝置性能與傳統裝置進行比較。研究了該裝置中的電流和電子注入。 (ii) 將基於磷光發光體的白光OLEDs視為未來照明和螢幕應用中的潛在材料。依據白光的定義，發白光需要將補色（比如藍色和黃色或橘色）或原色（紅,綠,藍）進行混合。本研究中，為了使用水溶液製程獲得一個簡單的白光OLEDs單色發光層向4,4′-Bis(N-carbazolyl)-1,1′-biphenyl (CBP) 的基質中加入了iridium(III) [bis(4,6-difuoro phenyl)-pyridinato-N,C2′]picolinate (FIrpic), tris[2-phenylpyri dinato-C2,N] iridium (III) (Ir(ppy)3) 以及bis[2-(1-isoquinolinyl-N) phenyl-C] (2,4-pentanedionato-O2,O4) iridium (III) (Ir(piq)2acac) 等三種磷光染料。觀察了製程的效率以及白光發光情況。 (iii) 為了使用水溶液製程獲得高性能OLEDs，一個非常重要的前提是形成均勻的無定形膜，而這主要取決於水溶製程的材料。通過將商用小分子作為混合基質進行水溶製程中製作了高效的柔性藍光OLEDs。柔性藍光OLEDs的水溶製程混合基質是摻雜了4,4′ ,4″-tri (N-carbazolyl)triphenylamine (TCTA)的2,6-bis(3-(9H-carbazol-9-yl)phenyl)pyri dine (26DCzPPy)，研究考察了基質中TCTA的電洞傳輸。(iv) 使用轉印法製作了高效的多層軟性藍光OLEDs。為了克服水溶製程中在有機層之間出現的混合問題，在小分子層上使用了轉印法。採用建議的轉印法製造之多層軟性藍光OLEDs顯示其性能顯著強于旋塗裝置。

關鍵字

N-型摻雜OLEDs ； 混合白光OLEDs ； 水溶液製程、轉印、柔性OLEDs ； 藍色

並列摘要

This dissertation is about the engineering of high performance OLEDs, which includes the electron transport layer thermal evaporation and stamping in OLED solution-processes. The following work is included in this dissertation: (i) An n-type doping system of tris(8-hydroxy-quinolinato) aluminum (Alq3) doped 2-(hydroxyl) quinolone lithium (Liq) in hybrid white OLEDs is developed and its device performances are compared with the conventional device. The maximum current efficiency of 23.2 cd/A and power efficiency of 7.4 lm/W at 20 mA/cm2 were obtained from the n-type doping HWOLED device. (ii) White OLEDs based on phosphorescent emitters are regarded as potential candidates for future lighting and display applications. In this study three phosphorescent dyes are incorporated, iridium(III) [bis(4,6-difuoro phenyl)-pyridinato-N,C2′] picolinate (FIrpic), tris[2-phenylpyridinato-C2,N] iridium (III) (Ir(ppy)3) and bis[2-(1-isoquinolinyl-N) phenyl-C](2,4-pentanedionato-O2,O4) iridium(III) (Ir(piq)2 acac), into a host of 4,4′-Bis(N-carbazolyl)-1,1′-biphenyl (CBP) to achieve a simple single-emitting white OLED layer using the solution process. The current and power efficiencies of the blue device with FIrpic 20 wt% in chlorobenzene were 2.95 and 0.89 lm/W at 20 mA/cm2. The current efficiency of 3.1 cd/A at 20 mA/cm2 and the CIE coordinates of (0.31, 0.32) at 1000 cd/m2 were obtained from the white device. (iii) To achieve high-performance OLEDs using solution-processing, uniform amorphous film formation is a very important prerequisite, which depends strongly on the solution-process materials. Highly efficient flexible blue OLEDs were fabricated by solution-processing commercial small molecules as the mixed-hosts. The hole transporting 4,4′ ,4″ -tri(N-carbazolyl)triphenylamine (TCTA) doped with the host 2,6-bis(3-(9H- carbazol-9-yl)phenyl)pyridine (26DCzPPy) as the solution-processed mixed-host for flexible blue OLED was investigated. The device with TCTA doped host exhibits the luminance of 2800 cd/m2, current density of 14.00 cd/A and power efficiency of 4.3 lm/W at 20 mA/cm2. (iv) Efficient multilayered flexible blue OLEDs were fabricated using the stamping method with PDMS and release film as transfer film. In order to overcome the mixing problem that occurs between the organic layers during the solution-processes, the stamping method was utilized on a small molecule layer. At the current density of 20 mA/cm2, the flexible blue OLED with PDMS as transfer film stamping device shows current and power efficiencies of 5.2 cd/A and 1.5 lm/W, respectively. The multilayered flexible blue OLEDs manufactured using the proposed stamping method presented significantly over spin-coated devices.

並列關鍵字

N-type doping OLEDs ； Hybrid white OLEDs ； Solution-processing and stamping OLEDs ； Flexible blue OLEDs

參考文獻

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