One‐Pot Synthesis of Carboxyl‐Functionalized Rare Earth Fluoride Nanocrystals with Monodispersity, Ultrasmall Size and Very Bright Luminescence

Abstract

AbstractWe demonstrated a straightforward approach to the synthesis of ultrasmall, monodisperse and carboxyl‐functionalized rare earth (RE) fluoride nanocrystals via a one‐pot reaction by introducing poly(acrylic acid) (PAA) as a coordination agent and surfactant. The morphologies, crystal structure, surface groups, and luminescent properties of the PAA‐capped RE fluoride nanocrystals were investigated in detail by TEM, FTIR, and photoluminescence spectroscopy. The obtained RE fluoride nanocrystals were ultrasmall in size, monodisperse, and highly crystalline. FTIR spectra confirmed that the PAA molecules strongly coordinated to the surface of the nanocrystals, which allows the formation of transparent colloidal aqueous solutions. Successful coating of the LaF3 shell on the NaCeF4:Tb3+ nanocrystals can increase the luminescence efficiency and lifetimes of Tb3+ ions relative to the pure NaCeF4:Tb3+ core. This synthesis procedure could become a versatile approach for the straightforward synthesis of carboxyl‐functionalized nanocrystals with ultrasmall size and monodispersity.