Nearly Monodisperse Insulator Cs4PbX6 (X = Cl, Br, I) Nanocrystals, Their Mixed Halide Compositions, and Their Transformation into CsPbX3 Nanocrystals

• DOI: 10.1021/acs.nanolett.6b05262
• Publication Date: 2017-02-14T22:30:56Z
• Authors: Quinten A. Akkerman; Sungwook Park; Eros Radicchi; Francesca Nunzi; Edoardo Mosconi; Filippo De Angelis; Rosaria Brescia; Prachi Rastogi; Mirko Prato; Liberato Manna
• Keywords: Dispersity

We have developed a colloidal synthesis of nearly monodisperse nanocrystals pure Cs4PbX6 (X = Cl, Br, I) and their mixed halide compositions with sizes ranging from 9 to 37 nm. The optical absorption spectra these display sharp, high energy peak due transitions between states localized in individual PbX64- octahedra. These spectral features are insensitive the size particles agreement corresponding bulk materials. Samples composition exhibit bands that intermediate position those compounds. Furthermore, broaden different possible combinations coordination around Pb2+ ions. Both observations supportive fact [PbX6]4- octahedra electronically decoupled systems. Because large band gap (>3.2 eV), no excitonic emission visible range was observed. Cs4PbBr6 can be converted into green fluorescent CsPbBr3 by reaction an excess PbBr2 preservation distributions. insertion PbX2 provides means accessing CsPbX3 wide variety sizes, shapes, compositions, important aspect for development precisely tuned perovskite nanocrystal inks.