All-Inorganic Quantum-Dot LEDs Based on a Phase-Stabilized α-CsPbI3 Perovskite

Ya Kun Wang, Fanglong Yuan, Yitong Dong, Jiao Yang Li, Andrew Johnston, Bin Chen, Makhsud I. Saidaminov, Chun Zhou, Xiaopeng Zheng, Yi Hou, Koen Bertens, Hinako Ebe, Dongxin Ma, Zhengtao Deng, Shuai Yuan, Rui Chen, Laxmi Kishore Sagar, Jiakai Liu, James Fan, Peicheng LiXiyan Li, Yuan Gao, Man Keung Fung, Zheng Hong Lu, Osman M. Bakr, Liang Sheng Liao, Edward H. Sargent*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

223 Scopus citations

Abstract

The all-inorganic nature of CsPbI3 perovskites allows to enhance stability in perovskite devices. Research efforts have led to improved stability of the black phase in CsPbI3 films; however, these strategies—including strain and doping—are based on organic-ligand-capped perovskites, which prevent perovskites from forming the close-packed quantum dot (QD) solids necessary to achieve high charge and thermal transport. We developed an inorganic ligand exchange that leads to CsPbI3 QD films with superior phase stability and increased thermal transport. The atomic-ligand-exchanged QD films, once mechanically coupled, exhibit improved phase stability, and we link this to distributing strain across the film. Operando measurements of the temperature of the LEDs indicate that KI-exchanged QD films exhibit increased thermal transport compared to controls that rely on organic ligands. The LEDs exhibit a maximum EQE of 23 % with an electroluminescence emission centered at 640 nm (FWHM: ≈31 nm). These red LEDs provide an operating half-lifetime of 10 h (luminance of 200 cd m−2) and an operating stability that is 6× higher than that of control devices.

Original languageEnglish (US)
Pages (from-to)16164-16170
Number of pages7
JournalAngewandte Chemie - International Edition
Volume60
Issue number29
DOIs
StatePublished - Jul 12 2021

Keywords

  • CsPbI quantum dots
  • inorganic ligand exchange
  • perovskite LEDs
  • pure red emission
  • strain engineering

ASJC Scopus subject areas

  • General Chemistry
  • Catalysis

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