運用等效尾態及場效載子遷移率模型來分析有機發光二極體中的載子傳輸

Modeling of carrier transport in organic light emitting diode by considering tail states and field dependent mobility model

盧以昕(I-Hsin Lu)

指導教授 ： 吳育任

國立臺灣大學/電機資訊學院/光電工程學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.01467

摘要

由於有機發光二極體的各項優點，有機發光二極體有潛力成為下一代的照明選擇，對於有機發光二極體的發展及市場需由，人們需要研究更好的OLED發光效率，因此材料的研究變得十分的重要，對此，需要一套有效率且準確的有機元件模擬程式。
對於元件電性的建模，我們使用了一維Poisson與Drift-diffusion方程，並且考慮了有機材料中的等效尾態來模擬有機元件的電性，另外，我們同時也考慮了等效的場效載子遷移率模型，來描述載子在元件中的傳輸行為。藉由對照實驗及模擬結果，我們建立了一套等效的模擬方法。其中有許多值得討論的問題，例如，金屬及有機材料之間接面的問題，對此，我們使用了一些模擬上的方法來表現，並且討論接面對電性的影響。在載子遷移率模擬上，我們也發現了一些現象，例如載子的速度飽和等行為，對此，我們必須對場效載子遷移率模型做出修正來解決模擬的問題。另外，對於發光層的主-客材料混合問題，我們也提出了一套模擬方法，對於不同比例濃度的混合建立模型，以等效的方法來模擬電性，並且展示了一系列參數對電性趨勢的變化。對於發光區的討論，我們考慮了激子擴散方程，同時考慮了一些激子損失機制例如激子-激子殲滅，用來模擬元件中的發光效率，利用此套方法來建立一個有機發光二極體的電性模擬軟體。

關鍵字

有機發光二極體 ； 尾態 ； 載子遷移率 ； 激子擴散

並列摘要

Due to the advantages of the organic light-emitting diode(OLED), the OLED has the potential to become the candidate of the next generation display technology. Since the growing market of OLEDs, people need to improve the power efficiency of OLEDs. The study of materials properties becomes very important. As a result, we need to develop simulation program to numerically analyze the electrical properties of the organic devices.

To build a model for analyzing electrical properties, we used the 1D Poisson and drift-diffusion solver and made a suitable modification to the code. By considering tail states of organic materials, we analyze the electrical property of the organic materials. In addition, we also consider the field dependent mobility model to present the transport behavior of the carriers. By comparing the experiment and simulation results, we can build an effective model to analyze the experimental results. In this thesis, several issues will be analyzed. First, the contact issue between the metal and the organic layer need to be well considered. Second, for the mobility model, we found that velocity saturation model needs to be added to the field dependent model to limit the carrier velocity goes infinity. Finally, the host-guest system also has been analyzed. We build a simulation method to present this system with different doping concentrations. To analyze the emitting distribution in the active layer, we consider the exciton diffusion and exciton quenching mechanisms, such as the exciton-exciton annihilation. With this model, we can model the efficiency of the organic devices. In this thesis, we will demonstrate our approaches in modeling OLED devices.

並列關鍵字

organic light-emitting diode ； tail states ； field dependent mobility model ； exciton diffusion ； exciton quenching

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