Deep-blue organic light-emitting diodes based on a doublet d- f transition cerium(III) complex with 100% exciton utilization efficiency

Liding Wang; Zifeng Zhao; Ge Zhan; Huayi Fang; Hannan Yang; Tianyu Huang; Yuewei Zhang; Nan Jiang; Lian Duan; Zhiwei Liu; Zuqiang Bian; Zhenghong Lu; Chunhui Huang

doi:10.1038/s41377-020-00395-4

Deep-blue organic light-emitting diodes based on a doublet d- f transition cerium(III) complex with 100% exciton utilization efficiency

Light Sci Appl. 2020 Sep 8:9:157. doi: 10.1038/s41377-020-00395-4. eCollection 2020.

Authors

Liding Wang^#¹, Zifeng Zhao^#¹, Ge Zhan¹, Huayi Fang², Hannan Yang³, Tianyu Huang⁴, Yuewei Zhang⁴, Nan Jiang³, Lian Duan⁴, Zhiwei Liu¹, Zuqiang Bian¹, Zhenghong Lu³, Chunhui Huang¹

Affiliations

¹ Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory of Rare Earth Materials Chemistry and Applications, Beijing Engineering Technology Research Centre of Active Display, College of Chemistry and Molecular Engineering, Peking University, 100871 Beijing, China.
² Tianjin Key Lab for Rare Earth Materials and Applications, School of Materials Science and Engineering, Nankai University, 300350 Tianjin, China.
³ Department of Physics, Yunnan University, 2 Cuihu Bei Lu, 650091 Kunming, China.
⁴ Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, 100084 Beijing, China.

^# Contributed equally.

Abstract

Compared to red and green organic light-emitting diodes (OLEDs), blue OLEDs are still the bottleneck due to the lack of efficient emitters with simultaneous high exciton utilization efficiency (EUE) and short excited-state lifetime. Different from the fluorescence, phosphorescence, thermally activated delayed fluorescence (TADF), and organic radical materials traditionally used in OLEDs, we demonstrate herein a new type of emitter, cerium(III) complex Ce-1 with spin-allowed and parity-allowed d-f transition of the centre Ce³⁺ ion. The compound exhibits a high EUE up to 100% in OLEDs and a short excited-state lifetime of 42 ns, which is considerably faster than that achieved in efficient phosphorescence and TADF emitters. The optimized OLEDs show an average maximum external quantum efficiency (EQE) of 12.4% and Commission Internationale de L'Eclairage (CIE) coordinates of (0.146, 0.078).

Keywords: Optoelectronic devices and components; Organic LEDs.