Indolo[3,2,1-jk]carbazole Embedded Multiple-Resonance Fluorophors for Narrowband Deep-blue Electroluminescence with EQE≈34.7 % and CIEy ≈0.085

Jinbei Wei; Chen Zhang; Dongdong Zhang; Yuewei Zhang; Ziyang Liu; Zhiqiang Li; Gui Yu; Lian Duan

doi:10.1002/anie.202017328

Indolo[3,2,1-jk]carbazole Embedded Multiple-Resonance Fluorophors for Narrowband Deep-blue Electroluminescence with EQE≈34.7 % and CIE_y ≈0.085

Angew Chem Int Ed Engl. 2021 May 25;60(22):12269-12273. doi: 10.1002/anie.202017328. Epub 2021 Apr 26.

Authors

Jinbei Wei¹, Chen Zhang², Dongdong Zhang², Yuewei Zhang², Ziyang Liu², Zhiqiang Li³, Gui Yu^{1

4}, Lian Duan^{2

5}

Affiliations

¹ Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.
² Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China.
³ JiHua Laboratory, Foshan, 528200, Guangdong Province, P. R. China.
⁴ School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China.
⁵ Center for Flexible Electronics Technology, Tsinghua University, Beijing, 100084, P. R. China.

PMID: 33742743
DOI: 10.1002/anie.202017328

Abstract

Multiple-resonance (MR) organic emitters bearing small full-width at half-maximum (FWHMs) are of general interest in organic light-emitting diodes. Indolo[3,2,1-jk]carbazole (ICz) embedded MR-fluorophors have demonstrated extremely small FWHMs, yet in the violet region with low electroluminescence efficiency. Herein, a strategic implementation of ICz subunits into MR fluorophors is proposed by taking advantage of the synergetic effect of para-positioned nitrogen atoms to enhance electronic coupling to decrease emitting energy gap. Deep blue emitters peaking at 441 and 447 nm with FWHMs of only 18 and 21 nm are thereof obtained, respectively, accompanied by ≈90 % photo-luminance quantum yields. With the assistance of a thermally activated delayed fluorescence sensitizer to recycle excitons, the corresponding narrowband electroluminescent devices show unprecedent high maximum external quantum efficiencies of 32.0 % and 34.7 % with CIE_y of 0.10 and 0.085, respectively.

Keywords: deep blue emitter; high efficiency; multiple resonance; narrow bandwidth; sensitized fluorescence emission.

Abstract

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