title: Insight into the Ligand-Mediated Synthesis of Colloidal CsPbBr3 Perovskite Nanocrystals: The Role of Organic Acid, Base, and Cesium Precursors.
abstract: While convenient solution-based procedures have been realized for the synthesis of colloidal perovskite nanocrystals, the impact of surfactant ligands on the shape, size, and surface properties still remains poorly understood, which calls for a more detailed structure-morphology study. Herein we have systematically varied the hydrocarbon chain composition of carboxylic acids and amines to investigate the surface chemistry and the independent impact of acid and amine on the size and shape of perovskite nanocrystals. Solution phase studies on purified nanocrystal samples by (1)H NMR and IR spectroscopies have confirmed the presence of both carboxylate and alkylammonium ligands on surfaces, with the alkylammonium ligand being much more mobile and susceptible to detachment from the nanocrystal surfaces during polar solvent washes. Moreover, the chain length variation of carboxylic acids and amines, ranging from 18 carbons down to two carbons, has shown independent correlation to the size and shape of nanocrystals in addition to the temperature effect. We have additionally demonstrated that employing a more soluble cesium acetate precursor in place of the universally used Cs2CO3 results in enhanced processability without sacrificing optical properties, thus offering a more versatile recipe for perovskite nanocrystal synthesis that allows the use of organic acids and amines bearing chains shorter than eight carbon atoms. Overall our studies have shed light on the influence of ligand chemistry on crystal growth and stabilization of the nanocrystals, which opens the door to functionalizable perovskite nanocrsytals through surface ligand manipulation.
authors.affiliation: Department of Chemistry, School of Science, Xi'an Jiaotong University , Xianning West Road, 28, Xi'an, 710049, China.
authors.forename: Aizhao
authors.initials: A
authors.lastname: Pan
authors.forename: Bo
authors.initials: B
authors.lastname: He
authors.affiliation: Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences , Urumqi 830011, China.
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Fan
authors.affiliation: Department of Chemistry, University of California, Berkeley, and Kavli Energy NanoSciences Institute at Berkeley , Berkeley, California 94720, United States.
authors.forename: Zeke
authors.initials: Z
authors.lastname: Liu
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Urban
authors.affiliation: Department of Chemistry, University of California, Berkeley, and Kavli Energy NanoSciences Institute at Berkeley , Berkeley, California 94720, United States.
authors.forename: A Paul
authors.initials: AP
authors.lastname: Alivisatos
authors.affiliation: Department of Chemistry, School of Science, Xi'an Jiaotong University , Xianning West Road, 28, Xi'an, 710049, China.
authors.forename: Ling
authors.initials: L
authors.lastname: He
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
keywords: colloidal nanocrystal; nanocubes; nanoplatelets; perovskite; surface chemistry