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 Li; Xiyan Li; Yuan Gao; Man-Keung Fung; Zheng-Hong Lu; Osman M Bakr; Liang-Sheng Liao; Edward H Sargent

doi:10.1002/anie.202104812

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

Angew Chem Int Ed Engl. 2021 Jul 12;60(29):16164-16170. doi: 10.1002/anie.202104812. Epub 2021 Jun 14.

Authors

Ya-Kun Wang^{1

2}, Fanglong Yuan^{1

3}, Yitong Dong¹, Jiao-Yang Li², Andrew Johnston¹, Bin Chen¹, Makhsud I Saidaminov^{1

4}, Chun Zhou¹, Xiaopeng Zheng⁵, Yi Hou¹, Koen Bertens¹, Hinako Ebe¹, Dongxin Ma¹, Zhengtao Deng^{1

6}, Shuai Yuan², Rui Chen⁷, Laxmi Kishore Sagar¹, Jiakai Liu⁵, James Fan¹, Peicheng Li³, Xiyan Li¹, Yuan Gao¹, Man-Keung Fung², Zheng-Hong Lu³, Osman M Bakr⁵, Liang-Sheng Liao², Edward H Sargent¹

Affiliations

¹ Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada.
² Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu, 215123, P. R. China.
³ Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario, M5S 3G4, Canada.
⁴ Present address: Department of Chemistry and Electrical & Computer Engineering, Centre for Advanced Materials and Related Technologies (CAMTEC), University of Victoria, Victoria, British Columbia, Canada.
⁵ Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
⁶ College of Engineering and Applied Sciences, State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing, Jiangsu, 210023, P. R. China.
⁷ Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, P. R. China.

PMID: 33982380
DOI: 10.1002/anie.202104812

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.

Keywords: CsPbI3 quantum dots; inorganic ligand exchange; perovskite LEDs; pure red emission; strain engineering.

Abstract

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