臺灣博碩士論文加值系統

本論文主要探討微米尺寸有機發光二極體(Organic light-emitting diode, OLED)之光電特性，並與毫米尺寸元件進行相互比較。我們使用兩種微影製程去製作微米尺寸的OLED：(1)以光阻定義元件主動面積，以及(2)直接蝕刻ITO電極至微米尺寸。在典型的NPB/Alq3 OLED中，實驗發現毫米尺寸元件(10 mm2)的崩潰電流密度(Breakdown current density)約為1 A/cm2，但將元件面積縮小至微米尺寸時，崩潰電流密度可大幅提升數十倍，其中最小面積元件(25×25 μm2)的崩潰電流密度最大可達58.3 A/cm2。在兩種微影製程中，又以直接蝕刻ITO電極之元件的崩潰電流密度更高。更重要的是，微米尺寸元件的外部量子效率(External quantum efficiency, EQE)與毫米尺寸元件幾乎相同，代表在微型元件中高電流密度仍具備有效的複合發光，而微影製程並不會影響發光效率。
接著本論文將微影製程應用在高電流密度的BSB-Cz/PVK平板波導OLED的研究上。實驗結果中亦發現崩潰電流密度隨著元件面積縮小而提升，類似於NPB/Alq3元件之趨勢。此實驗製作之最小微米元件(20×2000 μm2)能乘載高達3 A/cm2的崩潰電流密度，而外部量子效率仍在1%以上。相較於面積10 mm2之元件，崩潰電流密度能提升將近15倍。雖然在最高的電流密度下仍未發現自發輻射放大的現象，但本論文成功展示出利用微型化製程提升OLED電流密度並維持高發光效率，此研究成果有助於未來進一步發展電激發有機雷射。

In this study, we discuss performance of micron-sized OLEDs, and compared with the millimetre-sized OLEDs. We use two lithography processes to fabricate micron-sized OLEDs. (1) The active area of OLED is defined by photoresist, (2) and etching ITO electrode to micron size. From the results, it can be seen that the breakdown current density of millimetre-sized OLED is 1 A/cm2. However, the breakdown current density of micron-sized OLEDs can rise to more than ten times. Among the micron-sized OLEDs, the maximum breakdown current density of 25×25 μm2 device is 58.3 A/cm2. Among two lithography processes, the breakdown current density of etching pattern-device is higher than blocking pattern-device. More importantly, the External quantum efficiency of micron-sized OLEDs are the same with millimetre-sized OLEDs. It can be seen that the high current density in the micron-sized OLEDs still possesses effective recombination luminescence, while the lithography process does not affect the luminous efficiency.
In this paper, the photolithography process is applied to BSB-Cz / PVK OLEDs with high current density. From the results, it can be seen that the device with smaller active area has a higher breakdown current density. The breakdown current density of the smallest micron-sized OLED (20×2000 μm2) fabricated in this experiment can rise to 3 A/cm2, and the external quantum efficiency is still above 1%. Compared to the device of 10 mm2, the breakdown current density can increase nearly 15 times. Although we didn’t find spontaneous emission amplification at the highest current densities, we still have successfully demonstrated the use of miniaturization process to enhance the OLED current density and maintain high luminous efficiency. The results of this research will be helpful to the further development of electrically excited organic laser in the future.

目錄
摘要 I
Abstract II
致謝 IV
目錄 V
圖目錄 VII
表目錄 X
第一章 緒論 1
前言 1
研究動機 2
第二章 基本理論 4
2.1有機發光二極體之基礎原理 4
2.1.1架構與發光原理 4
2.1.2載子注入與傳輸 5
2.1.4有機發光二極體的劣化因素 10
2.2有機發光二極體載子注入優化 11
2.3 OLED優化之文獻回顧 12
2.3.1微米級發光元件陰極面積變化之影響 12
2.3.2共混層之影響 15
第三章 實驗方法與架構 19
3.1 實驗儀器 19
3.2 實驗製程步驟 22
3.2.1 微影製程 22
3.2.2 元件製程 25
3.3 量測儀器 27
3.4 量測架構 28
3.5數據分析與計算 32
第四章 結果與討論 35
4.1 微米尺寸OLED的設計與製作 35
4.1.1 ITO電極圖形定義 35
4.1.2 ITO電極圖形測試 38
4.1.3 銀電極圖形 42
4.2 微型NPB/Alq3 OLED 44
4.2.1 NPB/Alq3 OLED之結構 44
4.2.2 不同電子注入層的比較 46
4.2.3不同寬度ITO的元件比較 50
4.2.4 不同光阻開孔面積之元件比較 52
4.2.5 小結 56
4.3 BSB-Cz/PVK平板波導元件 57
4.3.1 BSB-Cz/PVK平板波導元件之結構 57
4.3.2 不同電子注入層對BSB-Cz/PVK平板波導元件之影響 59
4.3.3不同寬度ITO的元件比較 63
4.3.4 小結 67
第五章 結論 69
參考文獻 71


 

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黃裕軒，「有機平板波導結構電激發光特性之研究」，國立中央大學，碩士論文，民國103年。
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