具9,9-二甲基吖啶取代之苯并咪唑菲啶化合物雙極材料之合成、性質探討及在磷光有機發光二極體之應用

Synthesis and Characterization of Acridine Substituted Benzimidazole Derivatives as Bipolar Materials for Organic Light-Emitting Diodes

謝宜樺(Yi-Hua Xie)

指導教授 ： 梁文傑

國立臺灣大學/理學院/化學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202101910

摘要

本篇研究合成一系列雙極主發光體 (bipolar host) 並將其應用在有機發光二極體的發光層中。根據過往之研究報導，吖啶 (acridine) 具有良好電洞傳輸能力及高三重態能階，而苯并咪唑 (benzimidazole) 具有良好的電子傳輸能力。本論文利用具有強推電子性的吖啶基團（9,9-dimethyl-9,10-dihydroacridine, dmac）修飾在苯并咪唑菲啶化合物（1,2-diphenyl-1H-benzo[d]imidazole, BIZ）C1苯環上不同位置之碳上，改善電洞注入能力的同時也縮小單重態與三重態之間的能階差（ΔEST），因此合成 4-dmacBIZ, 3-dmacBIZ, 2-dmacBIZ 三個雙偶極（bipolar）化合物，並進一步探討其性質。
在分子設計上，吖啶基團以碳氮鍵且正交鍵結（orthogonally linakge）之方式修飾在苯并咪唑環化菲啶化合物上，藉以維持高三重態能階。本研究也針對化合物之熱性質、光物理性質和電化學性質進行分析。除此之外，也透過X-Ray單晶繞射進行晶體結構排列的研究與討論。
以吖啶苯并咪唑菲啶化合物2-dmacBIZ作為主體發光材料，摻混15% DMAC-TRZ應用在藍色磷光有機發光二極體的元件製作。在元件初步測量相關性質結果顯示，電荷密度10mA/cm2 的驅動電壓為7.09V，最大亮度為4396 cd/m2，最大電流效率為42.10 cd/A，最大外部量子產率為10.98%。
以吖啶苯并咪唑菲啶化合物2-dmacBIZ作為主體發光材料，摻混15% PXZ-TRZ應用在綠色磷光有機發光二極體的元件製作。在元件初步測量相關性質結果顯示，電荷密度10mA/cm2 的驅動電壓為6.59 V最大亮度為8557 cd/m2，最大電流效率為52.34 cd/A，最大外部量子產率為11.32%。

關鍵字

雙極材料 ； 苯并咪唑 ； 咔唑 ； 吖啶 ； 有機發光二機體 ； 熱活化行延遲螢光

並列摘要

In this research, three bipolar compounds based on 9,9-dimethyl-9,10-dihydroacridine substituted 1,2-diphenyl-1H-benzo[d]imidazole have been synthesized. According to previous reports, 9,9-Dimethyl-9,10-dihydroacridine is a renowned hole-transporting moiety, and 1,2-diphenyl-1H-benzo[d]imidazole serves as a good electron transporting unit. Therefore, instead of the commonly used donor unit, carbazole, to further enhancing electron mobility and reducing the energy difference between singlet and triplet state, we integrate 9,9-Dimethyl-9,10-dihydroacridine unit to the C1 benzene ring of 1,2-diphenyl-1H-benzo[d]imidazole unit.
To synthesize molecules with a high triplet energy state, units are expected to be orthogonally linked with each other to twist the conformation and thus reduce the overlap between HOMO and LUMO. In addition, the results show that all of these compounds possess higher HOMO energy levels and a high triplet energy state as expected which make this series of compounds perfect candidates to serve as host materials in TADF OLED devices.
One of our novel host materials 2-dmacBIZ forms a DMAC-TRZ-doped emitting layer which the corresponding blue TADF OLED device shows performance with the driving voltage of 7.09 V, the maximum current efficiency of 42.1 cd/A, the maximum external quantum efficiency of 10.98%. Furthermore, the TADF green OLED device with 2-dmacBIZ doped with 15% PXZ-TRZ exhibits a driving voltage of 6.59 V, a maximum current efficiency of 52.34 cd/A, the maximum external quantum efficiency of 11.34%.

並列關鍵字

Bipolar materials ； benzimidazole ； carbazole ； acridine ； organic light-emitting diodes ； thermally activated delayed fluorescence

參考文獻

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