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白光有機發光二極體可應用作為液晶顯示幕背光源與全固化照明光源，因此是一極具商品化潛力之有機發光二極體，白光有機發光二極體可以由光之三原色混合而成，亦可由兩種互補色形成。至今已有許多研究專門研究如何提高白光有機發光二極體之色純度、穩定度以及亮度，本論文將對此領域的現況進展做一較完整介紹，特別是元件結構調變及高效率白光有機發光二極體。在本實驗中具有高色純度和穩定度的結構indium tin oxide (ITO) (100nm)/ Molybdenum trioxide (MoO3) (15nm)/ 4,4’-Bis(2,2-diphenylvinyl)-1,1’-biphenyl (DPVBi) (10nm)/ 5,6,11,12-tetraphenylnaphthacene (Rubrene) (0.2nm)/ DPVBi (24nm)/ Rubrene (0.2nm)/ DPVBi (6nm)/ 4,7-Diphenyl-1,10-phenanthroline (BPhen) : Cesium carbonate (Cs2Co3) (10nm) /Al (120nm) 已經被製作了。多超薄層的功能，如Rubrene，作為黃色發光層和捕獲層。在實驗中，我們發現MUTL具有優異的載子捕獲效果。因此，可以使正負載子在整個發光層中充分複合， 導致黃光和藍光產生激子的數量有相對增加，因而達到黃光和藍光的最佳互補產生高穩定性的白光。實驗結果表明，元件具有高色穩定度不會因為外加電壓的不同，而造成CIE座標會有太大的位移。 另一方面，我們將MoO3摻雜到NPB當中作為電洞傳輸層，使其增加電洞注入以及導電性。結果發現，元件效率獲得進一步改善，元件最起始作電壓可以在2.01V被獲得，亮度可以提升至12230 cd/cm2。最後，我們使用有系統的物理和電性分析於MoO3-doped NPB薄膜，在這當中發現MoO3-doped NPB薄膜會有電荷轉移的現象，而這現象可以確定是造成WOLED特性提升的重要原因。 Recently, organic light-emitting diodes (OLED) has attracted a great deal of attention as the new full-color displays and solid-state lighting technology. OLED superior characteristics such as high brightness, fast response time, wide viewing angle and low operating voltage make it with great potential for commercialization. Furthermore, the white organic light-emitting diode (WOLED) lighting technology has been extensively studied. And then, there are several methods to obtain WOLEDs, For example, using multi-layer stack of three primary colors (red, green and blue), two complementary colors (blue and yellow) and two or three colors of the dye doped into single host material.The structure of indium tin oxide (ITO) (100nm)/ Molybdenum trioxide (MoO3) (15nm)/ 4,4’-Bis(2,2-diphenylvinyl)-1,1’-biphenyl (DPVBi) (10nm)/ 5,6,11,12-tetraphenylnaphthacene (Rubrene) (0.2nm)/ DPVBi (24nm)/ Rubrene (0.2nm)/ DPVBi (6nm)/ 4,7-Diphenyl-1,10-phenanthroline (BPhen) : Cesium carbonate (Cs2Co3) (10nm) /Al (120nm) with high color purity and stability white organic light-emitting diode (WOLED) was fabricated. The function of the multiple-ultra-thin layer (MUTL), such as Rubrene, is as the yellow light-emitting layer and trapping layer. The results show that the MUTL has excellent carrier capture effect, resulting in high color stability of the device at different applied voltages. This study elucidates the optoelectronic properties of high efficiency white organic light-emitting diodes (WOLED) with molybdenum oxide (MoO3) doping into N, N0-di (naphthalene-1-yl)–N, N0-diphenyl-benzidine (NPB) as a p-doping hole-transport layer (p-HTL). The device with a MoO3- doping NPB layer shows a turn-on voltage of 2.01 V and the maximum power efficiency 4.6 lm/W. The X-ray photoelectron spectroscopy (XPS) and UV-vis-NIR absorption spectra of MoO3-doping NPB layer revealed that the MoO3-doping NPB p-HTL had an improvement on holes injection. The improvement is caused by the formation of the charge transfer (CT) complex (NPB+-MoO3－) that is generated by doping MoO3 into NPB, markedly increasing the number of holes carrier, improving the balance of the electrons and holes in recombination zone. The pure white light emission with Commissions Internationale De L’Eclairage (CIE) coordinates of (0.335, 0.321) was achieved at the operating voltage of 6 V. This device shows the maximum luminance of 12230 cd/cm2 and the maximum luminous efficiency of 7.01 cd/A at an operating voltage of 7 V. |