Tunable luminescence and energy transfer of Tb3+/Eu3+ co-doped cubic CaCO3 nanoparticles

A series of Tb3+, Eu3+ singly or doubly doped CaCO3 phosphors have been synthesized by carbonation method. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and photoluminescence (PL) spectroscopy. The results show that the synthesized samples are all pure calcite CaCO3. The obtained samples have a cubic morphology with about 20 nm length. Under UV excitation, CaCO3:Tb3+, CaCO3:Eu3+ nanoparticles exhibit strong green and red emission, respectively. By adjusting the relative doping concentration of Tb3+ and Eu3+ ions in the CaCO3 host, the different color hues of green, red, and white light can be obtained. It has been verified through the luminescence spectra and decay curves that there exists an effective energy transfer from the Tb3+ to Eu3+ ions in CaCO3:Tb3+/Eu3+ and the form of energy transfer from Tb3+ to Eu3+ is dipole-quadrupole mechanism.