銀奈米結構增益發光元件出光效率之研究

Enhanced Light Extraction Efficiency of Light-Emitting Devices by Ag Nanostructures

彭凱鈺(Kai-Yu Peng)

指導教授 ： 吳建國 ； 姚永德

大同大學/工程學院/材料工程學系所/碩士(2009年)

摘要

近年來有機發光元件(organic light-emitting devices，OLED)已成為新興的平面顯示器產業，目前最重要的是提升元件的發光效率。事實上，從元件內部產生的光子大約只有20%是能被有效利用的，所以如何將光子導出元件外部，是現今重要的課題。本文利用奈米球微影術(Nanosphere Lithography，NSL)製備二維光子晶體(photonic crystal，PC)結構，以二維光子晶體視為一散射介質，將元件內部的光子抽取(extract)出來，而增加發光元件的外部量子效率(external quantum efficiency)。
在本研究中利用聚苯乙烯(polystyrene，PS)奈米球在PET基板上製作大面積、單層排列之六方最密堆積結構，然後將PET基板當作亮度增強膜(brightness enhancement film)直接貼附在OLED上，以增強元件的輝度。另一方面，利用奈米球微影術配合反應式離子蝕刻以及鍍膜之技術，在ITO玻璃基板上製備不同尺寸與厚度的金屬網狀奈米結構，藉以粗糙化基板表面，進而降低全反射，增強光的外部耦合效應，使得被限制在元件中的光散射出去，提升發光元件的亮度。

關鍵字

有機發光元件 ； 奈米球微影術 ； 光子晶體 ； 外部量子效率 ； 亮度增強膜 ； 金屬網狀結構

並列摘要

Organic light-emitting devices (OLED) has become an oncoming flat panel industry in recent years, and the key issue is to promote the luminous efficiency of the devices. In fact, only a small fraction (20%) of the total ptotons generated inside the OLED are generally useable, how to extract the photons from the OLED is an important topic nowadays. Two-dimensional photonic crystal (PC) structures are fabricated by using NSL technique in this study, and the two-dimensional photonic crystal structures is acted as a scattering medium to extract the light to the outer medium efficiency, in order to enhance the external quantum efficiency of the OLED.
A large area (PET) substrate contained single-layer polystyrene nanosphere arrays with hexagonal close-packed structures, and then attached it on OLED acted as a brightness enhancement film to enhance the luminance of the devices. On the other hand, using the NSL as a template combined with the reactive ion etching (RIE) and thin film deposition techniques to fabricate metallic network nanostructures with different sizes and thicknesses on ITO/glass substrates. The out-coupling of light could be enhanced due to the roughened surface reduces internal light reflection and scatters the light outward caused the coherent scattering of the internally trapped light.

並列關鍵字

organic light-emitting devices ； nanosphere lithography ； photonic crystal ； external quantum efficiency ； brightness enhancement film ； metallic network nanostructures

參考文獻

[1] Young Rag Do, Yoon-Chang kim, Young-Woo Song and Yong-Hee Lee, “Enhanced light extraction efficiency from organic light emitting diodes by insertion of two dimensional photonic crystal structure”, J. Appl. Phys. Vol.96, No.12, pp.7629-7636 (2004)

[3]Shen-Yu Hsu, Ming-Chang Lee, Kuang-Li Lee and Pei-Kuen Wei, “Extraction enhancement in organic light emitting devices by using metallic nanowire arrays”, Appl. Phys. Lett. 92, 013303 (2008)

[4] A. L. Burin and M. A. Ratner, “Exciton Migration and Cathode Quenching in Organic Light Emitting Diodes”, J. Phys. Chem. A 104, pp.4704-4710 (2000)

[5] 呂紹瑋, “利用自組裝奈米球微影術製備矽化物奈米點陣及二維有序奈米結構之研究”, 國立中央大學, 碩士論文 (2006)

[7] G. M. Whitesides and B. Grzybowski, “Self-Assembly and All Scales”, Science 295, pp.2418-2421 (2002)