Facile surfactant- and template-free synthesis and luminescence properties of needle-like calcite CaCO3:Eu3+ phosphors

Abstract

Needle-like CaCO₃:Eu³⁺ calcite phosphors have been successfully synthesized by a simple carbonization method in an ethylene glycol–H₂O system without using any surfactant, catalyst, or template. The as-obtained samples were characterized by means of XRD, FT-IR, SEM, TEM, HRTEM, SAED, and PL techniques. The XRD and FT-IR results demonstrate that the product is a pure calcite phase. The SEM and TEM images indicate that the morphology of the as-prepared calcite CaCO₃:Eu³⁺ nanoparticles is needle-like. The possible formation mechanism of the needle-like CaCO₃:Eu³⁺ calcite has been proposed based on a series of pH-dependent experiments. The needle-like CaCO₃:Eu³⁺ calcite nanoparticles exhibit much stronger red emission under UV light excitation than cubic and spindle-like CaCO₃:Eu³⁺ calcite nanoparticles.