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All‐Inorganic Quantum‐Dot LEDs Based on a Phase‐Stabilized α‐CsPbI 3 Perovskite
Author(s) -
Wang YaKun,
Yuan Fanglong,
Dong Yitong,
Li JiaoYang,
Johnston Andrew,
Chen Bin,
Saidaminov Makhsud I.,
Zhou Chun,
Zheng Xiaopeng,
Hou Yi,
Bertens Koen,
Ebe Hinako,
Ma Dongxin,
Deng Zhengtao,
Yuan Shuai,
Chen Rui,
Sagar Laxmi Kishore,
Liu Jiakai,
Fan James,
Li Peicheng,
Li Xiyan,
Gao Yuan,
Fung ManKeung,
Lu ZhengHong,
Bakr Osman M.,
Liao LiangSheng,
Sargent Edward H.
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202104812
Subject(s) - perovskite (structure) , electroluminescence , light emitting diode , quantum dot , thermal stability , materials science , phase (matter) , full width at half maximum , optoelectronics , ligand (biochemistry) , doping , nanotechnology , chemistry , crystallography , organic chemistry , biochemistry , receptor , layer (electronics)
The all‐inorganic nature of CsPbI 3 perovskites allows to enhance stability in perovskite devices. Research efforts have led to improved stability of the black phase in CsPbI 3 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 CsPbI 3 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.