Highly Efficient and Air-Stable Lanthanide EuII Complex: New Emitter in Organic Light Emitting Diodes

Ge Zhan; Liding Wang; Zifeng Zhao; Peiyu Fang; Zuqiang Bian; Zhiwei Liu

doi:10.1002/anie.202008423

Highly Efficient and Air-Stable Lanthanide Eu^II Complex: New Emitter in Organic Light Emitting Diodes

Angew Chem Int Ed Engl. 2020 Oct 19;59(43):19011-19015. doi: 10.1002/anie.202008423. Epub 2020 Aug 24.

Authors

Ge Zhan¹, Liding Wang¹, Zifeng Zhao¹, Peiyu Fang¹, Zuqiang Bian¹, Zhiwei Liu¹

Affiliation

¹ Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.

PMID: 32643262
DOI: 10.1002/anie.202008423

Abstract

Luminescent Eu^II complexes with a characteristic 5d-4f transition have potential applications in many fields. However, their instability in ambient conditions impedes further exploration and application. Herein, we report two new Eu^II complexes, bis[hydrotris(3-trifluoromethylpyrazolyl)borate]europium(II) (Eu-1) and bis[hydrotris(3-methylpyrazolyl)borate]europium(II) (Eu-2). Intriguingly, the blue emissive Eu-1 showed high air stability arising from fluorine protection and close molecular packing, as maintaining a photoluminescence quantum yield (PLQY) of 91 % (initial 96 %) upon exposure to air over 2200 hours. While the orange emissive Eu-2 showed a maximum luminance of 30620 cd m^-2 , and a maximum external quantum efficiency (EQE) of 6.5 %, corresponding to an exciton utilization efficiency around 100 % in organic light-emitting diodes (OLEDs). These results could inspire further research on stable and efficient Eu^II complexes and their application in OLEDs.

Keywords: d-f transitions; electroluminescence; europium(II) complexes; lanthanide complexes; photoluminescence.

Abstract

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