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標題: | 氮取代雜環為主體之電子傳輸材料設計、合成及應用 Design, Synthesis and Characterization of N-heteroaromatic-based Derivatives and Application to Electron Transporting Materials |
作者: | Shih-Chun Lin 林士竣 |
指導教授: | 汪根欉(Ken-Tsung Wong) |
關鍵字: | 電子傳輸材料,ATRP光催化劑,近紅外光,熱活化延遲螢光,激發錯合物, Electron transporting materials,ATRP Photocatalyst,NIR-OLEDs,TADF,exciplex, |
出版年 : | 2020 |
學位: | 碩士 |
摘要: | 近年有機發光材料發展蓬勃,目前已發展至第三代熱活化延遲螢光(Thermally Activated Delayed fluorescence, TADF) 材料。第二代磷光材料利用有機金屬錯合物放出磷光,但鉑及銥金屬的稀少性及高成本使得純有機TADF分子可望成為新的替代方案,然而要兼具TADF性質及放光的高效率也是其設計之難處。近期以物理性混摻電子予體及電子受體的激發活化錯合物 (Exciplex) 逐漸受到高度關注,比起 TADF 分子利用化學鍵連結電子予體及受體。激發活化錯合物將電子予體及受體分別設計不僅利於調控能階高低使單重/三重態能階差縮小,以熱活化的方式有效利用三重態激子,達到100% 的內部量子產率。 本論文中主要探討準線型及星狀結構對電子傳輸材料的影響。在激發錯合物中,作為電子受體並搭配合適的電子予體,使用於有機光電元件的主體材料或放光層。第二章探討吡啶及三嗪核心準線型電子受體,引入間位取代阻斷共軛,以維持高能階及三重激發態能量,並於末端修飾上氰基利於電子注入。利用此特質調控元件材層之分子排列,增強水平方向的躍遷偶極,進而提高元件出光效率。第三章利用三嗪及嘧啶星狀TADF分子作為電子受體,利用其分子內的雙極 (Bipolar) 設計有利電子及電洞良好的傳輸。以三嗪及嘧啶為核心,引入末端的氰基修飾延伸共軛,調整電子受體能階,並與合適電子予體搭配,可將激發錯合物的放光由綠光調整至橘光。 第四章以七員氮呯為主體,相對於五六員環的分子設計,氮呯具非芳香化特性因此具有十分強的推電子特質,有助於提高分子能階,作為薄膜光電偵測元件之阻擋層使用可降低暗電流提高偵測動態範圍。合成出的p-Az分子擁有高HOMO能階及可見的n-pi*吸收峰顯示分子容易氧化且激發後能藉快速的系間轉換產生三重激發子,文獻中常利用於光聚合反應催化劑之應用。七環分子構型扭曲,且尚未有文獻詳細探討結構之特殊性,此系列後續極具有開發潛能。 OLEDs are widely applied in modern display recently. However, the cost is still high due to the adoption of rare metals. Thermally activated delayed fluorescence (TADF) materials become a popular research topic since it can harvest all excitons to give nearly 100% quantum efficiency. A strategy of synthesizing TADF molecules is to control the HOMO-LUMO overlap. Nevertheless, the synthesis is challenged and suffered from the lack of reliable prediction of energy level of the effective moiety in these molecules. In contrast to TADF materials, the exciplex-based system having the electron and hole distribute on different molecules not only can realize nearly zero ΔEST, which maximizes the exciplex with theoretical 100% quantum yield as TADF molecules did, but also can reduce the synthetic difficulty and provides flexible manipulation of energy level. My research mainly focuses on the influence between quasi-linear star-shaped Electron Transporting Materials (ETMs) as electron acceptors for exciplex-based system. These materials can be utilized as host materials or emitting layers in exciplex-based OLEDs. The research of ETMs is mainly focused on its thermal stability and electron mobility. In second chapter, the quasi-linear configuration is applied to the ETMs for conjugation interruption to elevate triplet energy and maintain large energy bandgap. According to literature, the introduction of cyano group has a beneficial effect to electron injection and mobility. On the other hand, the star-shaped molecules are known for its high thermal stability in electron semiconducting materials. In third chapter, the research involves the star-shaped structure with pyrimidine- and triazine-building blocks which have the advantage of strong electron-deficient characteristics, thermal stability and suitable energy level. The introduction of cyano group extends conjugation, contributing to the red-shifted emission in exciplex-based system. In the last chapter, a novel N-seven-membered ring, Azepine, has been synthesized and applied to organic optoelectronic materials. Azepine derivatives are non-aromatics with strong electron-donating abilities to elevate the energy levels. p-Az has great potential as electron-blocking materials in organic photodetectors for dynamic range enhancement. It has been treated as photocatalysts for atom-transfer radical polymerization (ATRP). The research on azepine is limited by far, and the structure-property relationship of its derivatives have not been identified. This research elucidates the structural-property relationship of azepine derivatives and provides useful information for the development of N-heteroatomic derivatives to ETMs. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/16090 |
DOI: | 10.6342/NTU202002138 |
全文授權: | 未授權 |
顯示於系所單位: | 化學系 |
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