有機聚集誘導發光元件與載子產生層之研究

Investigation of aggregation-induced emission-based organic light-emitting diodes and charge generation layer

何丞永(CHENG-YUNG HO)

指導教授 ： 林昶宇 ； 張志豪

中原大學/工學院/機械工程學系/碩士(2022年)

https://doi.org/10.6840/cycu202201437

摘要

聚集誘導發光(Aggregation-induced emission，簡稱AIE)，成為近年來許多研究團隊探究的方向，已經證明其中的四苯乙烯(Tetraphenylethylene，簡稱 TPE) 基團是能夠表現出優異聚集誘導發光特性的核心分子，在本文研究中，提出使用不同的基團來置換 TPE 基團的其中一苯環來形成新的衍生物，使其仍保有聚集誘導發光之特性。
本論文將探討三種由立陶宛考那斯科技大學Saulius Grigalevicius 團隊所研發的藍光AIE材料，分子設計的核心為 TPE 基團，於其中的一個苯環上以咔唑基團作替代，並且分別接上二苯基碸、苯甲腈、二苯基甲酮於咔唑基團9號位，分別命名為 GK(1)、GK(2)、GK(3)，本系列材料都具有雙載子傳輸能力和高熱穩定性，論文將運用此系列材料來製作有機發光元件，探討其結構對於電致發光特性之影響。
元件將分為兩個部分討論，第一部分採摻雜式發光層之元件設計，元件的最大外部量子效率為 4.1% (8.7 cd/A、3.2 lm/W)，最大亮度為 18474 cd/m2，第二部分採非摻雜式發光層之元件設計，元件的最大外部量子效率為 3.9% (10.2 cd/A、10.6 lm/W)，最大亮度為 39661 cd/m2。
第二部分為針對串聯式元件中的載子產生層(Charge generation layer，簡稱 CGL)結構進行探討，目標希望能設計出具高載子產生率的CGL結構，使能有效提升串聯元件效率及亮度，我們參考文獻中所提出的多組異質結構對結構，進行結構改良及優化，我們所設計出的CGL結構較為簡單，是在雙異質節對中間插入一薄Li2CO3層，其電流密度能與六組異質節對之CGL結構相近，故能大幅減少製程時間，我們進一步利用紅光串聯式元件驗證，結果證明該結構與文獻相近結構相比，可大幅提升元件之電性。此深具潛力的CGL結構，未來亦可應用在誘導聚集放光材料的串聯式元件設計，提升元件效率及良率。

關鍵字

聚集誘導發光 ； 載子產生層 ； 有機發光元件 ； 串聯式元件

並列摘要

Aggregation-induced emission (AIE) has become the research direction of many research teams in recent years. It has been proved that the Tetraphenylethylene (TPE) is the core molecule for generating excellent aggregation-induced emission characteristics (AIE). In this work, we proposed to replace one of the benzene rings of the TPE group by carbazole and connected with hydrogen sulfonylbenzene, hydrogen cyanide. Named GK(1), GK(2), GK(3).All compounds were selected as emitters to investigate their electroluminescence applications.
Aggregation-induced emission (AIE) has drawn much attention in recent years. It has been proved that tetraphenylethylene (TPE) is one promising core molecule for generating excellent AIE characteristics. This work designed and synthesized molecules that use triphenylethene-carbazole moieties decorated with different substitutions and harvested wide energy bandgaps. We proposed that hydrogen sulfonylbenzene, or hydrogen cyanide, were respectively used to connect with triphenylethene-carbazole moieties, which were named GK(1), GK(2), and GK(3). The photoluminescence spectra of the synthesized molecules measured using tetrahydrofuran-water solution presented strong blue emissions, confirming their AIE property. Then, these synthesized compounds were selected as emitters to investigate their electroluminescence applications.
The doped blue-emitting organic light-emitting diodes (OLEDs) with compound GK(2) exhibited satisfactory peak efficiency of 8.7 cd/A and high maximum luminance of 18474 cd/m2. In comparison, the peak efficiency of the GK(2)-based sky-blue OLEDs with a non-doped emitting layer was 10.2 cd/A with an even superior peak luminance of 39661 cd/m2. Blue-emitting AIE OLEDs have rarely presented such high luminance values, and this improvement can facilitate the development of white-emitting OLEDs (WOLEDs) for lighting applications.
The second part of this thesis discusses the charge generation layer (CGL) in the tandem OLED. The target is to design a structure with a high capability of generating carriers, which enables the regulation of the carrier balance in fabricating tandem OLED. The multi-paired organic heterojunction (OHJ) structure was selected as the basic structure for further improvement and optimization. The optimized CGL structure consists of a thin Li2CO3 layer sandwiched between two OHJs, which performs quite similarly to the structure of six OHJs. The optimized CGL structure could simplify the multi-paired CGL reported in the literature and thus improve the device's electrical properties. The red phosphorescent tandem devices with our CGL structures exhibited satisfactory performance, demonstrating the potential of our designed CGL.

並列關鍵字

Aggregation-induced emission ； Charge generation layer ； OLED ； Tandem OLED

參考文獻

參考文獻

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