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標題: | 高效率有機發光元件之研究 Investigation of High efficiency Organic Lighting Emitting Devices |
作者: | Yi-Hsiang Huang 黃奕翔 |
指導教授: | 吳忠幟 |
關鍵字: | 有機發光元件,導電高分子,透明陽極,高效率, OLEDs,high efficiency,outcoupling,conducting polymers,transparent electrodes, |
出版年 : | 2014 |
學位: | 博士 |
摘要: | 隨著能源意識的提升,以及攜帶型裝置的應用,有機發光元件因具有自發光、省電、高反應速度、可撓曲等特性,因而成為下一代顯示器的發展重點,在本論文中,我們提出具有潛力的高效率有機發光元件結構,並藉由元件的製作並與理論計算結果相比較來確認其有效性。
首先我們使用透明高分子導體PEDOT:PSS取代傳統ITO作為有機發光元件透明陽極來製作具有高出光效率ITO-free有機發光元件。由模擬結果可知,使用低折射率PEDOT:PSS來取代ITO作為電極可有效減少波導膜態並增加總出光的效率比例(可達60.1%,高於ITO元件之 51.3%)。實驗結果顯示,使用PEDOT:PSS作為透明陽極並搭配出光透鏡,OLED總外部效率可達~44.1%,能量效率 (Power Efficiency) 達183.2 lm/W。 另外, PEDOT:PSS也常用來做OLED的電洞注入層高分子材料,我們研究使用低折射率的PEDOT:PSS搭配高折射率的ITO光來調控OLED合適的微共振腔效應。藉由數值計算我們可以得到OLED最佳的出光效率達35%,若使用外部出光技術總外部效率可達58%。實驗結果顯示,以PEDOT:PSS搭配ITO的有機發光元件,不使用外部出光透鏡時外部效率可達33.7%,加入外部出光透鏡更可高達54.3%,以此簡單便捷的設計就可以大幅提升傳統有機元件的發光效率極限。 With the consciousness of energy conservation and innovation of portable devices, organic light emitting devices having power-saving, self-emissive, short response time and flexible characteristics are promising for the next-generation displays. In this dissertation, we proposed high-efficiency organic light emitting device structures utilizing the low refractive index and conducting property of the conducting polymer PEDOT:PSS. Devices were fabricated and measured for comparison with simulation results. Agreement of simulation and experiment results confirms the effectiveness of the designs. Firstly, we replaced ITO with the high-conductive conducting polymer PEDOT:PSS as the transparent anode to implement ITO-free organic light-emitting devices. The lower refractive index of PEDOT:PSS can reduce the index mismatch between the anode and the substrate, thus reducing the waveguide mode and increasing the overall sum of radiation- and substrate-mode ratios (60.1% for PEDOT device vs. 51.3% of ITO device). The experimental results demonstrated an overall EQE ~44.1% and a luminous efficiency up to 183.2 lm/W. Furthermore, PEDOT:PSS is also commonly used as the hole-injection layer in OLEDs. In our study, by judicious combination of the low-index PEDOT:PSS and high-index ITO in OLEDs to induce appropriate microcavity effects, simulation shows that very high optical coupling efficiencies of >35% and >58% to air and to substrate, respectively, can be obtained. Experiments have demonstrated an EQE of 33.7% for green phosphorescent OLEDs and even higher EQE of 54.3% by adopting the external out-coupling lens, unlocking the full potential of conducting polymers for high-efficiency OLEDs. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/18370 |
全文授權: | 未授權 |
顯示於系所單位: | 光電工程學研究所 |
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