Highly Efficient Near-Infrared Thermally Activated Delayed Fluorescent Emitters in Non-Doped Electroluminescent Devices

Mengyu Zhao; Mengke Li; Wei Li; Songyu Du; Zhenyu Chen; Ming Luo; Yi Qiu; Xumin Lu; Shengyi Yang; Zhichuan Wang; Jiashen Zhang; Shi-Jian Su; Ziyi Ge

doi:10.1002/anie.202210687

Highly Efficient Near-Infrared Thermally Activated Delayed Fluorescent Emitters in Non-Doped Electroluminescent Devices

Angew Chem Int Ed Engl. 2022 Oct 17;61(42):e202210687. doi: 10.1002/anie.202210687. Epub 2022 Aug 19.

Authors

Mengyu Zhao^{1

2

3}, Mengke Li⁴, Wei Li^{1

2}, Songyu Du^{1

2}, Zhenyu Chen^{1

2}, Ming Luo^{1

2}, Yi Qiu^{1

2}, Xumin Lu^{1

2}, Shengyi Yang⁵, Zhichuan Wang^{1

2}, Jiashen Zhang^{1

2}, Shi-Jian Su⁴, Ziyi Ge^{1

2}

Affiliations

¹ Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China.
² Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 315201, Ningbo, P. R. China.
³ Nano Science and Technology Institute, University of Science and Technology of China, Suzhou, 215123, P. R. China.
⁴ State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Wushan Road 381, Tianhe District, Guangzhou, 510640, Guangdong Province, P. R. China.
⁵ Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China.

PMID: 35920086
DOI: 10.1002/anie.202210687

Abstract

Constructing organic near-infrared (NIR) luminescent materials to confront the formidable barrier of "energy gap law" remains challenging. Herein, two NIR thermally activated delayed fluorescence (TADF) molecules named T-β-IQD and TIQD were developed by connecting N,N-diphenylnaphthalen-2-amine and triphenylamine with a novel electron withdrawing unit 6-(4-(tert-butyl)phenyl)-6H-indolo[2,3-b]quinoxaline-2,3-dicarbonitrile. It is confirmed NIR-TADF emitters concurrent with aggregation-induced emission effect, J-aggregate with intra- and intermolecular CN⋅⋅⋅H-C and C-H⋅⋅⋅π interactions, and large center-to-center distance in solid states can boost the emissive efficiencies both in thin films and non-doped organic light-emitting diodes (OLEDs). Consequently, the T-β-IQD-based non-doped NIR-OLED achieved the maximum external quantum efficiency (EQE_max ) of 9.44 % with emission peak at 711 nm, which is one of the highest efficiencies reported to date for non-doped NIR-OLEDs.

Keywords: Materials Science; Near-Infrared Luminophores; Organic Electronics; Organic Light-Emitting Diodes; Thermally Activated Delayed Fluorescence.

Abstract

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