奈米散射膜於有機發光元件之應用研究

Investigating Applications of Nanocomposite Scattering Films in Organic Light Emitting Devices

張宏偉(Hong-Wei Chang)

指導教授 ： 吳忠幟

國立臺灣大學/電機資訊學院/電子工程學研究所/博士(2012年)

https://doi.org/10.6342/NTU.2012.10420

摘要

有機發光二極體被視為下一世代的照明與顯示科技，而目前需解決的一大限制為改善元件的出光萃取率，以達到高效率的需求。在本論文中，我們研究製備奈米散射膜，透過摻雜奈米顆粒(nanoparticles)於高分子基底中(polymeric matrix) 使其具有可調控的光學特性，具有高散射性、高整體穿透性，並且具有表面平坦性以作為有機發光二極體的內部光耦合萃取層(outcoupling extraction layer)。
奈米散射膜之分析可透過積分穿透頻譜(total transmittance)、正向頻譜(direct transmittance)、以及霧度(haze)來分析奈米散射膜的光學性質；使用研究表面粗糙度(surface roughness)可了解奈米散射膜的表面平坦度；研究掃描式電子顯微儀(SEM)以及原子力顯微儀(AFM)來了解奈米散射膜的形貌。奈米散射膜具有高穿透性、高散射性以及低吸收性，使其可有效使用為出光萃取層；表面平坦性使其更可作為內部萃取層(internal extraction layers)使用，相較於外部萃取層(external extraction layers)可獲得更高的效率增益。
在本論文中，我們將所開發的奈米散射膜應用於各式先進的有機發光二極體中，包含可撓式有機發光二極體、白光有機發光二極體，以及透明/雙向有機發光二極體中，應用作為內部出光萃取層。結果可得知，本研究之奈米散射膜可有效的整合製備於各式有機發光二極體中作為內部出光萃取層。元件出光效益可明顯獲得改善，且出光顏色穩定度(color stability)也可獲得顯著的提升，未來具有相當潛力可廣泛的應用於先進有機發光二極體。

關鍵字

有機發光二極體 ； 奈米散射膜 ； 可撓式/軟性有機發光二極體 ； 白光有機發光二極體 ； 透明/雙向有機發光二極體

並列摘要

Organic light emitting diodes (OLEDs) have attractive features for next-generation display and lighting applications. Nevertheless, one current issue is how to improve the optical outcoupling efficiency of OLEDs for achieving higher efficiency. In this dissertation, we study how to develop a scattering medium by dispersing nanoparticles into a polymeric host matrix. By this method, we can fabricate nano-composite scattering films (NCSFs) with tunable optical characteristics, high integrated transmittance, high scattering capability, and flat surface, making them suitable for integration with OLEDs as internal optical extraction layer.
The optical characteristics of NCSFs were analyzed by integrated total transmittance (Ttotal), direct transmittance (Tdirect) and haze (Ttotal-Tdirect/Ttotal). The surface morphology was studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The developed nano-composite scattering films showed strong scattering capability for the visible wavelength range and flat surfaces, suitable for device integration as internal extraction layers.
In this study, we then applied the nano-composite scattering films in various types of OLEDs, including flexible OLEDs, white OLEDs, transparent/ bi-directional white OLEDs, as internal optical extraction layers for EQE and luminous efficiency enhancement, as well as color-quality improvement.
In summary, in this dissertation, we have successfully developed nano-composite scattering films as internal optical extraction layers for OLEDs. The outcoupling efficiency can be improved significantly, and the color stability over viewing angles can be improved well.

並列關鍵字

organic light-emitting devices (OLEDs) ； nano-composite scattering films (NCSFs) ； flexible OLEDs ； white OLEDs ； transparent/ bi-directional OLEDs

參考文獻

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