High-Performance Non-doped OLEDs with Nearly 100 % Exciton Use and Negligible Efficiency Roll-Off

Huijun Liu; Jiajie Zeng; Jingjing Guo; Han Nie; Zujin Zhao; Ben Zhong Tang

doi:10.1002/anie.201802060

High-Performance Non-doped OLEDs with Nearly 100 % Exciton Use and Negligible Efficiency Roll-Off

Angew Chem Int Ed Engl. 2018 Jul 20;57(30):9290-9294. doi: 10.1002/anie.201802060. Epub 2018 Jun 21.

Authors

Huijun Liu¹, Jiajie Zeng¹, Jingjing Guo¹, Han Nie¹, Zujin Zhao¹, Ben Zhong Tang^{1

2}

Affiliations

¹ Center for Aggregation-Induced Emission, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China.
² Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center, for Tissue Restoration and Reconstruction, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China.

PMID: 29856500
DOI: 10.1002/anie.201802060

Abstract

Non-doped organic light-emitting diodes (OLEDs) possess merits of higher stability and easier fabrication than doped devices. However, luminescent materials with high exciton use are generally unsuitable for non-doped OLEDs because of severe emission quenching and exciton annihilation in neat films. Herein, we wish to report a novel molecular design of integrating aggregation-induced delayed fluorescence (AIDF) moiety within host materials to explore efficient luminogens for non-doped OLEDs. By grafting 4-(phenoxazin-10-yl)benzoyl to common host materials, we develop a series of new luminescent materials with prominent AIDF property. Their neat films fluoresce strongly and can fully harvest both singlet and triplet excitons with suppressed exciton annihilation. Non-doped OLEDs of these AIDF luminogens exhibit excellent luminance (ca. 100000 cd m^-2 ), outstanding external quantum efficiencies (21.4-22.6 %), negligible efficiency roll-off and improved operational stability. To the best of our knowledge, these are the most efficient non-doped OLEDs reported so far. This convenient and versatile molecular design is of high significance for the advance of non-doped OLEDs.

Keywords: aggregation-induced delayed fluorescence; efficiency roll-off; excitons; organic light-emitting diodes; thermally activated delayed fluorescence.