A Multifunctional "Halide-Equivalent" Anion Enabling Efficient CsPb(Br/I)3 Nanocrystals Pure-Red Light-Emitting Diodes with External Quantum Efficiency Exceeding 23

Jibin Zhang; Tiankai Zhang; Zhuangzhuang Ma; Fanglong Yuan; Xin Zhou; Heyong Wang; Zhe Liu; Jian Qing; Hongting Chen; Xinjian Li; Shijian Su; Jianing Xie; Zhifeng Shi; Lintao Hou; Chongxin Shan

doi:10.1002/adma.202209002

A Multifunctional "Halide-Equivalent" Anion Enabling Efficient CsPb(Br/I)₃ Nanocrystals Pure-Red Light-Emitting Diodes with External Quantum Efficiency Exceeding 23

Adv Mater. 2023 Feb;35(8):e2209002. doi: 10.1002/adma.202209002. Epub 2022 Dec 22.

Authors

Jibin Zhang^{1

2}, Tiankai Zhang³, Zhuangzhuang Ma¹, Fanglong Yuan^{3

4}, Xin Zhou², Heyong Wang^{3

5}, Zhe Liu⁶, Jian Qing², Hongting Chen², Xinjian Li¹, Shijian Su⁶, Jianing Xie⁷, Zhifeng Shi¹, Lintao Hou², Chongxin Shan¹

Affiliations

¹ Key Laboratory of Materials Physics of Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Daxue Road 75, Zhengzhou, 450052, China.
² Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Siyuan laboratory, Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy Materials, Department of Physics, Jinan University, Guangzhou, 510632, P. R. China.
³ Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, SE-58183, Sweden.
⁴ Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875, China.
⁵ Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, Milan, 20133, Italy.
⁶ State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, China.
⁷ Guangdong-Hong Kong-Macao Joint Laboratory for Intelligent Micro-Nano Optoelectronic Technology, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, 528225, China.

PMID: 36493461
DOI: 10.1002/adma.202209002

Abstract

Pure-red perovskite LEDs (PeLEDs) based on CsPb(Br/I)₃ nanocrystals (NCs) usually suffer from a compromise in emission efficiency and spectral stability on account of the surface halide vacancies-induced nonradiative recombination loss, halide phase segregation, and self-doping effect. Herein, a "halide-equivalent" anion of benzenesulfonate (BS^- ) is introduced into CsPb(Br/I)₃ NCs as multifunctional additive to simultaneously address the above challenging issues. Joint experiment-theory characterizations reveal that the BS^- can not only passivate the uncoordinated Pb²⁺ -related defects at the surface of NCs, but also increase the formation energy of halide vacancies. Moreover, because of the strong electron-withdrawing property of sulfonate group, electrons are expected to transfer from the CsPb(Br/I)₃ NC to BS^- for reducing the self-doping effect and altering the n-type behavior of CsPb(Br/I)₃ NCs to near ambipolarity. Eventually, synergistic boost in device performance is achieved for pure-red PeLEDs with CIE coordinates of (0.70, 0.30) and a champion external quantum efficiency of 23.5%, which is one of the best value among the ever-reported red PeLEDs approaching to the Rec. 2020 red primary color. Moreover, the BS^- -modified PeLED exhibits negligible wavelength shift under different operating voltages. This strategy paves an efficient way for improving the efficiency and stability of pure-red PeLEDs.

Keywords: CsPb(Br/I) 3 nanocrystals; halide vacancies; phase separation; pure-red light-emitting diodes; self-doping effect.

Abstract

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