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標題: | 螺旋吖啶與嘧啶雙極材料之合成、性質探討以及在藍光有機發光二極體的應用 Synthesis and Characterization of Spiro-acridine and Pyrimidine Bipolar Material and Their Application in Blue Light Organic Light Emitting Diodes |
作者: | 司涵昀 Han-Yun Szu |
指導教授: | 梁文傑 MAN-KIT LEUNG |
關鍵字: | 熱延遲螢光,能階差(ΔEST),螺旋吖啶基團,嘧啶基團,咔唑, thermal activated delayed fluorescence,energy gap (ΔEST),spiroacridine unit,pyrimidine unit,carbazole, |
出版年 : | 2023 |
學位: | 碩士 |
摘要: | 近年來有機發光二極體元件中熱延遲螢光(TADF)蓬勃發展,其核心的概念就是透過分子的設計來降低ΔEST,ΔEST會和分子內最高填滿分子軌域 (Highest Occupied Molecular Orbital,HOMO),和最低未填滿分子軌域 (Lowest Unoccupied Molecular Orbital,LUMO)的重疊度呈正相關。因此,如何降低HOMO和LUMO的重疊度就成為設計TADF分子終至關重要的議題。本篇論文研究則是設計具有強的推子性螺旋吖啶基團修飾在拉電子能力的嘧啶,在不同位置分別接上咔唑及三咔唑,合成出一系列化合物,來探討不同取代基對於光色、量子產率的影響。同時我們以紫外可見光光譜(UV-Vis)、磷光放射光譜(PL)、螢光放射光譜(FL)進行光物理性質探討;以 X-ray 單晶繞射探討分子的堆疊和排列;以差式脈波伏安法(DPV)、循環伏安法(CV)進行電化學性質探討;以差示掃描量熱法(DSC)及熱重分析儀(TGA)來測量熱性質的探討,研究是否利用此架構能使供體基團螺旋吖啶與中心苯環扭轉角度增大,使HOMO及LUMO分別落在螺旋吖啶基團及嘧啶上,使HOMO及LUMO重疊軌域變小,縮小單重態-三重態能階差 ΔEST,合成出更有潛力的熱延遲螢(TADF)材料並同時增加化合物的分子量來提高熱穩定性。在有機發光二極體的元件應用上
將化合物作為發光層的材料,應用在單層元件中,經過摻雜客發光體ID5之不同濃度優化,以4SpAc35CbzPy 的元件表現最好,最大亮度為3003 cd/m2,最大電流效率為 65 cd/A,最大功率為 59.3 lm/W,外部量子效率可達 27.38 %,CIE 座標為 (0.191, 0.411),屬於藍綠光的範圍。 In recent years, there has been a vigorous development of Thermally Activated Delayed Fluorescence (TADF) in organic light-emitting diode (OLED) components. The core concept of TADF is to reduce the energy gap (ΔEST) through molecular design, which is positively correlated with the overlap between the Highest Occupied Molecular Orbital (HOMO) and the Lowest Unoccupied Molecular Orbital (LUMO) within the molecule. Consequently, minimizing the overlap between HOMO and LUMO has become a crucial aspect in designing TADF molecules. The focus of this research paper is the design of spiroacridine units with strong electron-withdrawing properties to modify the electron-accepting abilities of pyrimidine. Various substituents were introduced at different positions, including carbazole and tricarbazole, to synthesize a series of compounds aimed at investigating the impact of different substituents on photoluminescence and quantum yield. Furthermore, a comprehensive study of the optical properties was conducted using UV-Vis spectroscopy, photoluminescence spectroscopy (PL), and fluorescence spectroscopy (FL). The molecular stacking and arrangement were explored through X-ray single crystal diffraction. Electrochemical properties were probed using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). Thermal properties were investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The investigation aimed to determine whether the proposed structure could lead to increased twist angles between the donor group spiroacridine and the central benzene ring, causing HOMO and LUMO to localize on the spiroacridine unit and pyrimidine, respectively. This localization would reduce the overlap of HOMO and LUMO orbitals, subsequently decreasing the singlet-triplet energy gap (ΔEST) and synthesizing more promising TADF materials with increased molecular weight to enhance thermal stability. In the context of OLED device applications, these compounds were employed as emissive materials in single-layer devices. After optimizing the doping concentration of the emitter ID5, the device based on 4SpAc35CbzPy exhibited the best performance. It achieved a maximum luminance of 3003 cd/m², a maximum current efficiency of 65 cd/A, a maximum power efficiency of 59.3 lm/W, and an external quantum efficiency of 27.38%. The CIE coordinates were (0.191, 0.411), falling within the range of blue-green light. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/91291 |
DOI: | 10.6342/NTU202304230 |
全文授權: | 未授權 |
顯示於系所單位: | 化學系 |
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