title: Emulsion Synthesis of Size-Tunable CH3NH3PbBr3 Quantum Dots: An Alternative Route toward Efficient Light-Emitting Diodes.
abstract: We report a facile nonaqueous emulsion synthesis of colloidal halide perovskite quantum dots by controlled addition of a demulsifier into an emulsion of precursors. The size of resulting CH3NH3PbBr3 quantum dots can be tuned from 2 to 8 nm by varying the amount of demulsifier. Moreover, this emulsion synthesis also allows the purification of these quantum dots by precipitation from the colloidal solution and obtains solid-state powder which can be redissolved for thin film coating and device fabrication. The photoluminescence quantum yields of the quantum dots is generally in the range of 80-92%, and can be well-preserved after purification (∼80%). Green light-emitting diodes fabricated comprising a spin-cast layer of the colloidal CH3NH3PbBr3 quantum dots exhibited maximum current efficiency of 4.5 cd/A, power efficiency of 3.5 lm/W, and external quantum efficiency of 1.1%. This provides an alternative route toward high efficient solution-processed perovskite-based light-emitting diodes. In addition, the emulsion synthesis is versatile and can be extended for the fabrication of inorganic halide perovskite colloidal CsPbBr3 nanocrystals.
authors.forename: Hailong
authors.initials: H
authors.lastname: Huang
authors.affiliation: Department of Materials Sciences and Engineering, California NanoSystems Institute, Henry Samuli School of Engineering and Applied Science, University of California , Los Angeles, California, United States.
authors.forename: Fangchao
authors.initials: F
authors.lastname: Zhao
authors.forename: Lige
authors.initials: L
authors.lastname: Liu
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
authors.forename: Xian-gang
authors.initials: XG
authors.lastname: Wu
authors.forename: Lijie
authors.initials: L
authors.lastname: Shi
authors.forename: Bingsuo
authors.initials: B
authors.lastname: Zou
authors.affiliation: Department of Materials Sciences and Engineering, California NanoSystems Institute, Henry Samuli School of Engineering and Applied Science, University of California , Los Angeles, California, United States.
authors.forename: Qibing
authors.initials: Q
authors.lastname: Pei
authors.forename: Haizheng
authors.initials: H
authors.lastname: Zhong
keywords: electroluminescence; emulsion synthesis; halide perovskite; light-emitting diodes; quantum dot; semiconductor nanocrystals