{"title":"Crafting host materials for narrowband blue OLEDs with low efficiency roll-off by the medium-ring strategy","authors":"Yuanyuan Bao, Anping Luo, Jingbo Lan, Junjie Liu, Zhengyang Bin, Jingsong You","doi":"10.1007/s11426-024-2057-7","DOIUrl":null,"url":null,"abstract":"<p>The pursuit of high-performance narrowband blue organic light-emitting diodes (OLEDs) is of paramount importance in both academic research and industrial applications. While obvious strides have been made in the design of narrowband blue emitters, the development of appropriate host materials has evidently trailed behind. Herein, we introduce a medium-ring strategy for crafting host molecules based on the heptagonal tribenzo[<i>b,d,f</i>]azepine (TBA) unit. The twisted three-dimensional (3D) architecture of the TBA framework not only endows the host molecules with fast hole-transporting pathways but also effectively reduces exciton quenching. Equipped with two TBA units, DTBA, synthesized with ease, demonstrates a huge horizontal orientation factor (<i>Θ</i><sub>//</sub>) of 93.5% and a broad emission spectrum for accelerating the energy transfer process in the emitting layer, which contributes to enhancing device performance. We have fabricated high-performance narrowband blue OLEDs using DTBA as the host, FIrpic as the phosphor sensitizer, and the widely used boron-nitrogen-containing multiple resonance emitter BCz-BN. These devices exhibit a maximum external quantum efficiency (EQE<sub>max</sub>) as high as 31.0% with an impressively low-efficiency roll-off. Even at a high luminance level of 10,000 cd m<sup>−2</sup>, the EQE value remains noteworthy at 20.3%, marking a significant advancement in BCz-BN-based devices.</p>","PeriodicalId":772,"journal":{"name":"Science China Chemistry","volume":null,"pages":null},"PeriodicalIF":10.4000,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Science China Chemistry","FirstCategoryId":"1","ListUrlMain":"https://doi.org/10.1007/s11426-024-2057-7","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
The pursuit of high-performance narrowband blue organic light-emitting diodes (OLEDs) is of paramount importance in both academic research and industrial applications. While obvious strides have been made in the design of narrowband blue emitters, the development of appropriate host materials has evidently trailed behind. Herein, we introduce a medium-ring strategy for crafting host molecules based on the heptagonal tribenzo[b,d,f]azepine (TBA) unit. The twisted three-dimensional (3D) architecture of the TBA framework not only endows the host molecules with fast hole-transporting pathways but also effectively reduces exciton quenching. Equipped with two TBA units, DTBA, synthesized with ease, demonstrates a huge horizontal orientation factor (Θ//) of 93.5% and a broad emission spectrum for accelerating the energy transfer process in the emitting layer, which contributes to enhancing device performance. We have fabricated high-performance narrowband blue OLEDs using DTBA as the host, FIrpic as the phosphor sensitizer, and the widely used boron-nitrogen-containing multiple resonance emitter BCz-BN. These devices exhibit a maximum external quantum efficiency (EQEmax) as high as 31.0% with an impressively low-efficiency roll-off. Even at a high luminance level of 10,000 cd m−2, the EQE value remains noteworthy at 20.3%, marking a significant advancement in BCz-BN-based devices.
期刊介绍:
Science China Chemistry, co-sponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China and published by Science China Press, publishes high-quality original research in both basic and applied chemistry. Indexed by Science Citation Index, it is a premier academic journal in the field.
Categories of articles include:
Highlights. Brief summaries and scholarly comments on recent research achievements in any field of chemistry.
Perspectives. Concise reports on thelatest chemistry trends of interest to scientists worldwide, including discussions of research breakthroughs and interpretations of important science and funding policies.
Reviews. In-depth summaries of representative results and achievements of the past 5–10 years in selected topics based on or closely related to the research expertise of the authors, providing a thorough assessment of the significance, current status, and future research directions of the field.