T型寡聚芴之佔態與未佔態能階

Abstract

由於有機發光二極體具有許多與半導體相似的性質，例如容易製造、低成本以及廣視角與低能量消耗，已被廣泛地應用在顯示以及照明上。為了達到全彩顯示與白光照明，現今的研究著重於短波長的有機發光元件。寡聚芴化合物具有良好的熱穩定性以及高的發光量子產率，應用在有機發光元件上也有高亮度與低操作電壓的特性。在本論文中，利用以同步輻射為光源的光電子光譜學被用來研究T型寡聚芴的被佔態能階的電子構與能障性質。透過此技術可量測其基本性質與研究T型寡聚芴與氟化鋰介面所發生的化學反應，並發現有電荷轉移的現象以及氟化鋰對於T型寡聚芴具有n-type參雜的效果。此外也利用了反轉光電子光譜學去研究其未佔態能階的電子結構，並透過結合用光電子光譜學與反轉光電子光譜學所獲得的光譜，可以決定其完整的電子能階結構與能隙大小。

Because of similar properties to semiconductor, easy fabrication process, lower cost, large viewing angle, lower power consumption, and high brightness, OLEDs become scientific and commercial significant and gradually played an important role in display technology. In order to achieve full color display and lighting applications, numerous research groups focus on visible light range and are devoted to short wavelength emitting organic materials in recent years. Fluorene-based polymers possess thermal stability and high PL quantum yields. Besides, used in OLEDs are found giving high brightness, low operating voltage. In this thesis, we successfully investigate the occupied electronic structure and energy levels of the T-homologous oligofluorenes via synchrotron radiation photoemission spectroscopy. The basic properties of T-homologous oligofluorenes are measured and chemical reaction at the interfaces formed by T-homologous oligofluorenes and LiF is also studied and we observed that charge transfer and n-type doping effect occurs when LiF is deposited on T-homologous oligofluorenes. In addition, we introduce the principle of IPES and the design of photon detector and measure the spectrum of unoccupied states above Fermi level via IPES. We try to combination of PES and IPES spectra the whole electronic structure and the bad gap is determined.