交流電驅動有機發光二極體及自組裝分子修飾石墨烯場效電晶體之特性研究

Investigation of Device Characteristics in Alternating Current-Driven Organic Light-emitting Diodes and Graphene Field Effect Transistors Modified with Self-Assembled Monolayer on Silicon Dioxide Substrates

劉尚奕(Shang-Yi Liu)

指導教授 ： 吳志毅

國立臺灣大學/電機資訊學院/光電工程學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.03149

摘要

薄膜顯示器成為近幾十年來顯示產業上的主流。其中，可撓性顯示器更是近年來的新寵。在當今的顯示器結構中，有機材料配合石墨烯場效電晶體被譽為被寄予厚望的新興方案之一。本文中，我們將探討交流電驅動有機發光二極體及利用新型轉印方式之化學分子修飾石墨烯場效電晶體的元件特性。
在第一部分，我們以熱蒸鍍之氟化鋰作為絕緣層製作交流電驅動有機發光二極體。此氟化鋰作為絕緣層的元件具有較低的起始電壓，相較於過去以較製程較複雜的二氧化鉿絕緣層元件，此交流電驅動有機發光二極體有相等程度的元件亮度。另外，我們利用紫外光電子能譜及反轉式電子能譜分析交流電驅動有機發光二極體元件各層的電子能階，進而解釋此元件的發光原理。利用以上能譜所得之對應電子能階，我們便可解釋元件的光及電特性。
在第二部分，我們以聚合物及非聚合物轉印方式製作利用自組裝膜修飾之基板的石墨烯場效電晶體。此電晶體經基板修飾後，能有大幅度性能上的提升。同時，我們也討論此兩種轉印方式對於元件表現的影響。我們所製作最佳的元件在室溫下具備高達11000 cm2/V∙s的載子遷移率，相較於過去文獻中以自組裝膜修飾之元件高出許多。最後，我們以混合溶液的方式進行石墨烯的參雜，進而做成P及N型石墨烯場效電晶體。

關鍵字

交流電驅動有機發光二極體 ； 光電子能譜 ； 反轉式電子能譜 ； 石墨烯場效電晶體 ； 自組裝分子薄膜 ； 無高分子材料轉印 ； 混合溶液參雜

並列摘要

In the past decades, thin film displays caught all eyes and had risen to the dominating position in display technology, as a potential branch in which flexible displays become the new favorite these days. In the present thin film display structure, organic materials along with graphene transistors are regarded as one of the potential ways to realize this concept. In this work, we investigate the device characteristics of organic light-emitting diodes (OLEDs), especially driven by alternating current (AC), and graphene field effect transistors (GFETs) with evolved transfer technique and modified substrates.
In the first part, we demonstrate an AC-driven OLED with LiF insulating layers using simple thermal evaporation. The device is equipped with relatively lower turn-on voltage and favorable luminance, which is nearly identical to the devices with HfO2 insulating layers reported. Ultraviolet photoemission spectroscopy (UPS) and inverse photoemission spectroscopy (IPES) are employed simultaneously in an ultrahigh vacuum (UHV) chamber to examine the electronic band structure of AC-driven OLED, which enables us to deeply investigate the operating principle of AC-driven OLED. In addition, the electronic band structure obtained fully explains optical properties and electrical characteristics of AC-driven OLEDs.
In the second part, we demonstrate GFETs transferred via polymer-involved and polymer-free techniques on self-assembled monolayer (SAM)-modified substrates. The GFETs on SAM-coated SiO2 substrates all show better performance as compared to those on bare SiO2 substrates. Several verifications on the two transfer techniques are also investigated in parallel. The best GFETs on SAM-coated SiO2 substrate via polymer-free transfer technique exhibits extremely high mobility of 11000 cm2/V∙s at room temperature, which is much higher than the devices in prior researches. Furthermore, the mixed-solvent doped graphene is adopted as channels of p or n-type GFETs as well and the doping effect is considerably effective.

並列關鍵字

AC-driven OLED ； photoemission spectroscopy ； inverse photoemission spectroscopy ； graphene field effect transistor ； self-assembled monolayer ； polymer-free ； mixed-solvent doping

參考文獻

[1] W. Helfrich and Schneide.Wg, "Recombination Radiation in Anthracene Crystals," Physical Review Letters, vol. 14, pp. 229-&, 1965.

[3] J. Kido, M. Kimura, and K. Nagai, "Multilayer White Light-Emitting Organic Electroluminescent Device," Science, vol. 267, pp. 1332-1334, Mar 3 1995.

[4] L. S. Liao, K. P. Klubek, and C. W. Tang, "High-efficiency tandem organic light-emitting diodes," Applied Physics Letters, vol. 84, p. 167, 2004.

[5] M. A. Baldo, D. F. O'Brien, Y. You, A. Shoustikov, S. Sibley, M. E. Thompson, et al., "Highly efficient phosphorescent emission from organic electroluminescent devices," Nature, vol. 395, pp. 151-154, Sep 10 1998.

[6] J. H. Burroughes, D. D. C. Bradley, A. R. Brown, R. N. Marks, K. Mackay, R. H. Friend, et al., "Light-Emitting-Diodes Based on Conjugated Polymers," Nature, vol. 347, pp. 539-541, Oct 11 1990.