有機發光二極體之有機與金屬界面動態特性模型進階擬合研究

利用P極化光反射光譜來量測有機發光元件之有機與金屬界面動態特性，當入射光滿足特定條件時，會在有機金屬界面產生表面電漿(Surface Plasmon Resonance, SPR)，即為表面電漿共振之光散射技術，由於此方法靈敏度極高，可偵測出界面動態情況的微小變化，並以簡形數值擬合法(Simplex Data Fitting)配合有機發光二極體模型探討有機與金屬界面間動態變化的情形。當有機材料與電極在操作狀態下，因載子的漂移會使得有機物質與電極間產生變化，文獻證實在有機層與陰極層間會形成一中間層，將此定義為一介電層，構成本研究所使用之五層結構之有機發光二極體模型；推論在電極陽極與有機層也會形成另一介電層，構成另一六層結構之有機發光二極體模型。由實驗量測無有機層元件並擬合其ITO光學參數來比較實驗與理論的差異性；使用單層有機層元件量測反射光譜圖並以五層及六層模型作數值擬合，最佳所得的二層介電層之光學參數(n、k、d)分別為：三變數擬合－折射率8.73-6.98i，厚度為14.05nm，誤差容許度為2.5E-3，四變數擬合－折射率1.74-5.96i，厚度為9.19nm，其誤差容許度可達2.76E-5，說明介電層是具高折射高吸收，其性質偏向金屬材質的特性，且在操作狀態下，n、k值會提升0.02-0.3，與外加電壓成正比關係，可確定元件在操作狀態下，由於介電層有能量通過，使介電層產生新的鍵結物質而使n、k值上升，由此證實本實驗之理論模型的正確性。

關鍵字

有機發光二極體；有機金屬界面；表面電漿共振；簡形數值擬合法

並列摘要

This thesis research is to study the dynamical characteristics of organic/metal interface in organic light-emitting devices (OLED) by means of measuring P-polarized He-Ne laser reflectivity spectra in which surface plasmon resonance (SPR) sensitive to interfacial properties can be generated as incident laser satisfies specific condition. Due to carrier injections at interfaces, it’s been confirmed that there is an intermediate layer between organic and metal layers in OLED during device operation. The dynamical properties of organic/metal interface can be characterized by optical constants of this intermediate layer as our experimental data fit to multi-layer OLED optical models with 3 or 4 adjustable variables. Our experimental results showed that the optical constants (n, k) and thickness (d) are (8.73, 6.98) and 14.05nm respectively in best fit with 3 variables. The fitting tolerance can reach 2.5E-3. The optical constants (n, k) and thickness (d) are (1.74, 5.96) and 9.19nm respectively in best fit with 4 variables. The fitting tolerance can reach 2.76E-5. It also revealed that the characteristic of this intermediate layer is similar to metal due to its high reflection and high absorption. The optical constants increased in range of 0.02-0.3 during device operation as driving voltage increased.

並列關鍵字

OLED ； organic/metal interface ； surface plasmon resonance ； simplex data fitting method

參考文獻

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國際替代計量

有機發光二極體之有機與金屬界面動態特性模型進階擬合研究

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