Preparation And Luminescence Properties Of Eu³⁺ Dopeu Doped CaCO₃with Different Morphologies

In order to meet the long run demand and energy-saving consideration, rare earthluminescent material has become most promising green material for its advantages ofbeing inexhaustible and pollution-free, and has received more and more attention invarious fields of application, such as lighting, display and biomedical fields.Researchers have focused on the choice of the host. In the present paper, we preparedluminescent material by using CaCO₃as a host, which is due to convenient synthesisand much application in many chemical industry.（1） Micron Spherical Particle CaCO₃is widely used in the chemical，biologicaland medical fields for its good dispersity and flowability. Spherical calcium carbonateparticles have been prepared using sodium carboxymethyl cellulose （CMC） ascrystalline control agent in this paper. Different factors on the morphology andparticle size were studied. Meanwhile, optimal synthesis conditions of the sphericalCaCO₃were got. XRD, FTIR, SEM were used to characterize the products. Theresults indicated that the spherical particles were mainly consisted of calcite mixedwith a small part of vaterite, and the products have good sphericity and uniformparticle size at the range of about1-3μm.（2） Cubic and spindle CaCO₃nanoparticles with a small and uniform size havespecial performance, which are widely used in the rubber, paper, plastic and inkindustries as a filler or reinforcing material. It is common to prepare cubic and spindlecalcium carbonate nanoparticles with some additives in the previous literature. Here, we report a facile carbonation route to synthesize cubic and spindle CaCO₃nanoparticles without any additives. The influence factors of the controllablesynthesis of calcium carbonate crystals with different morphology were discussed,such as the concentration of Ca（OH）₂slurry, reaction temperature and flow rate ofCO₂and N₂. The optimum conditions for preparation cubic CaCO₃were as follows:the temperature of15oC, the flow rates of CO₂and N₂:0.5l/min and1l/min, theconcentration of Ca（OH）₂:1.0mol/L;The optimum condition for preparation spindleCaCO₃was determined as follows: the temperature of40oC, the flow rates of CO₂and N₂:0.5l/min and1l/min, the concentration of Ca（OH）₂:1.0mol/L.（3） Under the optimum conditions, spherical, cubic and spindle CaCO₃:Eu³⁺areprepared. Compared the XRD of non-doped CaCO₃and Eu³⁺-doped CaCO₃, we findthat the crystalline of calcium carbonate are not changed. We measure thefluorescence spectra of Eu³⁺-doped calcium carbonate with different morphology andcompare the effect of morphology and size on the luminescence intensity. The reasonis further analyzed.