臺灣博碩士論文加值系統

本論文是利用同步輻射光源探討Rubrene和金屬(Mg和Al)的介面反應，藉由價帶能譜與核層能譜分析Rubrene和金屬的介面電子結構。在Mg/Rubrene的蒸鍍過程中，起初Mg擴散(diffusion)進入Rubrene層且和Rubrene產生反應。Mg有charge transfer給Rubrene，進而產生介面偶極。在Rubrene/Mg的能譜中，顯示Rubrene應是化學吸附在Mg金屬。其真空能階的偏移起因於介面的Pillow Effect，然而卻被Charge transfer所減弱。在另一次Rubrene/Mg的實驗裡，因為Rubrene未除氣乾淨，其蒸鍍過程中造成了Mg基底表面有氧化的現象，所以 Rubrene極有可能和基底上的氧反應形成Rubrene的氧化物，造成HOMO波峰的變寬以及不對稱，也因此使得Rubrene分子極化，而造成真空能階偏移。而在Rubrene/Al介面，由價帶與核層能譜可知其為物理吸附。真空能階偏移遠小於文獻所得，應是蒸鍍過程表面形成氧化鋁減弱了Pillow Effect。在Rubrene與Mg和Al的介面中皆發現有介面偶極(Interfacial Dipole)的產生，導致真空能階偏移，使得電洞障壁(hole transfer barrier)增加，電子障壁(electron transfer barrier)減少，有利於電子的傳輸。本研究對Rubrene的除氣未至臻善，導致基底氧化物的產生和Rubrene譜形的些許變異，將再進一步做實驗加以改善及驗證。

Using synchrotron-radiation photoemission spectroscopy, We have studied the interfacial properties between rubrene and metals (Mg, Al). For the Mg/rubrene system, upon Mg adsorption, Mg diffuses into rubrene and transfer charge to rubrene. When diffusion saturated, Mg atoms cluster on the surface and then form metallic Mg. The vacuum level shift is mainly attributed from the charge transfer. For the rubrene/Mg system, the valence band and core level spectra have shown that rubrene is chemisorption on a Mg surface. The unexpected vacuum level shift direction may be caused by a compromise among charge transfer and pillow effect. In another experiment, unsuccessfully-degassed rubrene source results in Mg oxidation. Since oxygen exists on the substrate, rubrene has a large possibility to form rubrene oxide. This results the broadening of HOMO peak and induces vacuum level shift. For the rubrene/Al system, the valence band and core level spectra have shown that rubrene physisorbes on a Al surface. The vacuum level shift results from the pillow effect. However, the smaller shift than that in the literature may be due to the formation of aluminum oxide on the substrate to reduce the interfacial dipole moment. The vacuum level shift was found due to the existence of interfacial dipole for rubrene/Mg and rubrene/Al interface, results in the reduction of an electron barrier This is good for electrons transfer at the interface. With respect to some drawbacks and uncertainties in this thesis, we will improve in next experiment and further confirm the interfacial properties of rubrene/Mg and rubrene/Al.

摘要 1
Abstract 2
誌謝 3
第一章 簡介 6
1-1有機太陽能電池簡介 6
1-2 Rubrene簡介與太陽能電池上的應用 9
1-3文獻回顧 12
1-4研究動機 16
第二章 實驗系統簡介 17
2-1 實驗原理 17
2-1.1 光電子能譜技術( Photoemission Spectroscopy, PES ) 17
2-1.2 價帶能譜 23
2-1.3核層能譜 24
2-2 實驗光源介紹 25
2-2.1同步輻射簡介 25
2-2.2 使用之光束線設計：LSGM光束線(Low-energy spherical grating monochromator beam line) 28
2-3實驗真空系統與儀器介紹 32
2-4 實驗過程 39
2-4.1試片準備: 39
2-4.3 清潔試片 44
2-4.4蒸鍍 Rubrene 44
2-4.5蒸鍍鎂(Mg) 45
2-4.6蒸鍍鋁(Al) 45
第三章 結果與討論 47
3-1 Mg/Rubrene 47
3-1.1 Mg/Rubrene 的價帶能譜(Valence-Band Spectroscopy) 47
3-1.2 Mg/Rubrene 的核層能譜(Core-Level Spectroscopy) 49
3-1.3 Mg/Rubrene的能階圖(Energy-Level Diagram) 50
3-2 Rubrene/Mg 56
3-2.1 Rubrene/Mg的價帶能譜(Valence-Band Spectroscopy) 56
3-2.2 Rubrene/Mg 的核層能譜(Core-Level Spectroscopy) 57
3-2.3 Rubrene/Mg的能階圖(Band Diagram) 58
3-2.4 未除氣乾淨之Rubrene的Rubrene/Mg價帶能譜(Valence-Band Spectroscopy) 64
3-2.5未除氣乾淨之Rubrene的Rubrene/Mg核層能譜(Core-Level Spectroscopy) 65
3-2.6 未除氣乾淨之Rubrene的Rubrene/Mg能階圖(Band Diagram) 66
3-3 Rubrene/Al 72
3-3.1 Rubrene/Al的價帶能譜(Valence-Band Spectroscopy) 72
3-3.2 Rubrene/Al的核層能譜(Core-Level Spectroscopy) 73
3-3.3 Rubrene/Al的能階圖(Energy-level Diagram) 74
第四章 結論 79
參考文獻 81

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