Controlled synthesis of calcite/vaterite/aragonite and their applications as red phosphors doped with Eu3+ ions

Abstract

Calcium carbonate (CaCO₃) particles including three anhydrous polymorphs (calcite/vaterite/aragonite) have been prepared in the absence and presence of sodium carboxyl methylcellulose (NaCMC), which further serve as hosts to prepare the phosphors doped with Eu³⁺. The as-obtained samples were characterized by means of XRD, SEM, and PL techniques. The experimental results reveal that vaterite, as a less stable polymorph, will transform into calcite in aqueous solution without any additive. In contrast, NaCMC can induce the formation of vaterite phase at 50 °C and the formation of aragonite phase at 90 °C in aqueous solution. In addition, the polymorph-dependent luminescence properties of CaCO₃:Eu³⁺ have been briefly studied by excitation spectra, emission spectra, PL decay curves and quantum yield.