以高散熱基板製作上發光型有機發光二極體

本論文在陽極結構Al/Au中，插入一層功函數及導電率均與Au較接近的Ni，避免Al、Au界面因Kirkendall孔洞而造成Al、Au剝離，使元件快速衰減。再以三層週期性的結構來應用於上發光有機發光二極體之陽極，其陽極的是由一層的鋁(AL) 及週期性的鎳(Ni) 與金(Au) 所構成。因為鋁為高反射率金屬，其功函數為4.1 eV 。而鎳與金為高功函數的金層，較高於鋁的功函數，所以可以有效的提高元件的陽極至有機層的電洞注入效果，鎳與金的功函數的值各為5.3 eV與5.1 eV。而陽極在Ni/Au 為2週期的情況下有較高的反射率和與微共振腔效果，因此得到最高的發光效率 7.99 cd/A ，較高於1週期Ni/Au 的6.85 cd/A 及3週期Ni/Au 的5.07 cd/A。研究使用具有高熱傳導率的二種基板。AlN基板，其熱傳導係數約為270 W/m•K，厚度為0.3mm。Cu基板其熱傳導係數約為約397 W/m•K，厚度為0.3mm。以散熱基板製作TOLED可利於元件操作時所產生之焦耳熱，能經由基板得到散逸，因此元件之發光效率在高電流密度下，衰減幅度會比使用玻璃基板之元件更平緩，能有效減少元件衰退之速度，使元件在高電流密度下有較高之隱定度。

關鍵字

有機發光二極體；上發光有機發光二極體

並列摘要

This study in anode structure Al/Au, inserted Ni, which work function and conductivity was closer to Au. The Al-Au interface under the room temperature, altogether has Au2Al, Au5Al2, Au4Al, and AuAl2 four kinds of possibilities produces. Intermetallic compound could cause crack, it increases with the time, it would finally make Al-Au peeled off completely.Avoid the contact surface of Au and Al be weakened by the Kirkendall void strips. The triple-metal-layer periodic structures in the anode for top-emission organic light emitting diodes (TEOLEDs) are studied in this study. The anode consists of aluminum (Al) and nickel/gold (Ni/Au) periodic structures. The Al is used for high reflectivity and Ni/Au for high work function by enhancing the hole injection from the anode into the organic hole injection layer. The Ni and Au work functions were measured at 5.3, 5.1 eV, respectively, which were higher than that of a single Al layer at 4.2 eV. This 2-pair Ni/Au anode device exhibits high reflectivity and reveals the microcavity effect to increase luminescence efficiency. 2 periodic on visible light range (400nm -800nm) reflection is 89.36% , relatively higher 1 periodic 85.15%.The optimum current efficiency with the 2-pair Ni/Au anode is increased up to 7.99 cd/A compared with the 1-pair Ni/Au anode (6.85 cd/A) and 3-pair Ni/Au anode (5.07 cd/A). The common OLED components are made on the glass substrate that the heat generated in operation due to high illumination or high current density will store up in the components due to lower heat conductivity of glass (1.38 W/m•K), which cause the components pre-matured life span. Therefore, this study takes the lead to use AIN substrate with high heat conductivity (approx. 270 W/m•K) and Cu (approx. 390 W/m•K) for making TEOLED, that the heat as generated in operation could be evacuated from substrate. Temperature and voltage relation are to examine the back income of the sample by infrared thermometer.The sample on Glass substrate will be burnt-out because the heat can’t dissipate under high temperature.High heat dissipation substrate could be evacuated the heat from substrate, so the device can operating on the higher voltage without burnt-out. The sample on AlN sub., best luminance and luminance efficiency, which is 9560 cd/m2 (@20V)and 7.36 cd/A, respectively.The sample on Cu sub., best luminance and luminance efficiency, which is 17600 cd/m2 (20V)and 8.76 cd/A, respectively.