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Nano Research

Article Title

Mechanosynthesis of polymer-stabilized lead bromide perovskites: Insight into the formation and phase conversion of nanoparticles

Authors

Guocan Jiang, Physical Chemistry, Technische Universität Dresden, Zellescher Weg 19, 01069 Dresden, Germany
Onur Erdem, Department of Physics, Department of Electrical and Electronics Engineering, and UNAM − Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara, Turkey
René Hübner, Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstrasse 400, 01328 Dresden, Germany
Maximilian Georgi, Physical Chemistry, Technische Universität Dresden, Zellescher Weg 19, 01069 Dresden, Germany
Wei Wei, Physical Chemistry, Technische Universität Dresden, Zellescher Weg 19, 01069 Dresden, Germany
Xuelin Fan, Physical Chemistry, Technische Universität Dresden, Zellescher Weg 19, 01069 Dresden, Germany
Jin Wang, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua 321004, China
Hilmi Volkan Demir, Department of Physics, Department of Electrical and Electronics Engineering, and UNAM − Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara, Turkey;LUMINOUS! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, School of Mathematical and Physical Sciences, School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798, Singapore
Nikolai Gaponik, Physical Chemistry, Technische Universität Dresden, Zellescher Weg 19, 01069 Dresden, Germany

Keywords

lead bromide perovskites, mechanosynthesis, polymer ligands, polymer micelles, poly(ethyleneimine)-induced phase conversion

Abstract

The application of polymers to replace oleylamine (OLA) and oleic acid (OA) as ligands for perovskite nanocrystals is an effective strategy to improve their stability and durability especially for the solution-based processing. Herein, we report a mechanosynthesis of lead bromide perovskite nanoparticles (NPs) stabilized by partially hydrolyzed poly(methyl methacrylate) (h-PMMA) and high- molecular-weight highly-branched poly(ethylenimine) (PEI-25K). The as-synthesized NP solutions exhibited green emission centered at 516 nm, possessing a narrow full-width at half-maximum of 17 nm and as high photoluminescence quantum yield (PL QY) as 85%, while showing excellent durability and resistance to polar solvents, e.g., methanol. The colloids of polymer-stabilized NPs were directly processable to form stable and strongly-emitting thin films and solids, making them attractive as gain media. Furthermore, the roles of h-PMMA and PEI-25K in the grinding process were studied in depth. The h-PMMA can form micelles in the grinding solvent of dichloromethane to act as size-regulating templates for the growth of NPs. The PEI-25K with large amounts of amino groups induced significant enrichment of PbBr2 in the reaction mixture, which in turn caused the formation of CsPb2Br5-mPbBr2 and CsPbBr3-Cs4PbBr6-nCsBr NPs. The presence of CsPbBr3-Cs4PbBr6-nCsBr NPs was responsible for the high PL QY, as the Cs4PbBr6 phase with a wide energy bandgap can passivate the surface defects of the CsPbBr3 phase. This work describes a direct and facile mechanosynthesis of polymer-coordinated perovskite NPs and promotes in-depth understanding of the formation and phase conversion for perovskite NPs in the grinding process.

Publisher

Tsinghua University Press

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