Proton-Prompted Ligand Exchange to Achieve High-Efficiency CsPbI3 Quantum Dot Light-Emitting Diodes

Yanming Li; Ming Deng; Xuanyu Zhang; Lei Qian; Chaoyu Xiang

doi:10.1007/s40820-024-01321-8

Proton-Prompted Ligand Exchange to Achieve High-Efficiency CsPbI₃ Quantum Dot Light-Emitting Diodes

Nanomicro Lett. 2024 Feb 1;16(1):105. doi: 10.1007/s40820-024-01321-8.

Authors

Yanming Li^#^{1

2}, Ming Deng^#^{1

2

3}, Xuanyu Zhang^#^{1

2

4}, Lei Qian^{1

2

5}, Chaoyu Xiang^{6

7

8}

Affiliations

¹ Laboratory of Advanced Nano-Optoelectronic Materials and Devices, Qianwan Institute of CNITECH, Ningbo, 315300, People's Republic of China.
² Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, People's Republic of China.
³ Faculty of Electrical Engineering and Computer Science, Ningbo University, Ningbo, 315211, Zhejiang, People's Republic of China.
⁴ University of Nottingham Ningbo China, Ningbo, 315100, People's Republic of China.
⁵ Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, 315201, People's Republic of China.
⁶ Laboratory of Advanced Nano-Optoelectronic Materials and Devices, Qianwan Institute of CNITECH, Ningbo, 315300, People's Republic of China. xiangchaoyu@nimte.ac.cn.
⁷ Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, People's Republic of China. xiangchaoyu@nimte.ac.cn.
⁸ Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, 315201, People's Republic of China. xiangchaoyu@nimte.ac.cn.

^# Contributed equally.

Abstract

CsPbI₃ perovskite quantum dots (QDs) are ideal materials for the next generation of red light-emitting diodes. However, the low phase stability of CsPbI₃ QDs and long-chain insulating capping ligands hinder the improvement of device performance. Traditional in-situ ligand replacement and ligand exchange after synthesis were often difficult to control. Here, we proposed a new ligand exchange strategy using a proton-prompted in-situ exchange of short 5-aminopentanoic acid ligands with long-chain oleic acid and oleylamine ligands to obtain stable small-size CsPbI₃ QDs. This exchange strategy maintained the size and morphology of CsPbI₃ QDs and improved the optical properties and the conductivity of CsPbI₃ QDs films. As a result, high-efficiency red QD-based light-emitting diodes with an emission wavelength of 645 nm demonstrated a record maximum external quantum efficiency of 24.45% and an operational half-life of 10.79 h.

Keywords: CsPbI3 perovskite quantum dots; Ligand exchange; Light-emitting diodes; Proton-prompted in-situ exchange.