Wang Ya-Kun, Yuan Fanglong, Dong Yitong, Li Jiao-Yang, 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 Man-Keung, Lu Zheng-Hong, Bakr Osman M, Liao Liang-Sheng, Sargent Edward H
Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada.
Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu, 215123, P. R. China.
Angew Chem Int Ed Engl. 2021 Jul 12;60(29):16164-16170. doi: 10.1002/anie.202104812. Epub 2021 Jun 14.
The all-inorganic nature of CsPbI perovskites allows to enhance stability in perovskite devices. Research efforts have led to improved stability of the black phase in CsPbI 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 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 ) and an operating stability that is 6× higher than that of control devices.
CsPbI钙钛矿的全无机性质有助于提高钙钛矿器件的稳定性。研究工作已使CsPbI薄膜中黑色相的稳定性得到改善；然而，这些策略——包括应变和掺杂——是基于有机配体封端的钙钛矿，这会阻碍钙钛矿形成实现高电荷和热传输所需的紧密堆积量子点（QD）固体。我们开发了一种无机配体交换方法，可得到具有卓越相稳定性和更高热传输性能的CsPbI量子点薄膜。原子配体交换后的量子点薄膜一旦实现机械耦合，其相稳定性就会提高，我们将此与薄膜上应变的分布联系起来。对发光二极管温度的原位测量表明，与依赖有机配体的对照样品相比，经KI交换的量子点薄膜热传输有所增加。这些发光二极管的最大外量子效率为23%，电致发光发射中心波长为640 nm（半高宽：≈31 nm）。这些红色发光二极管的工作半衰期为10 h（亮度为200 cd m ），工作稳定性比对照器件高6倍。
