Effect of Crystallite Size and Crystallinity on Photoluminescence Properties and Energy Transfer of Y6MoO12:Eu

The phosphors Y6MoO12:Eu3+ have been synthesized via citrate complexation method at different calcination temperatures. The evolutions of the crystal structure and the photoluminescence (PL) properties were characterized by means of powder X‐ray diffraction (XRD), Raman and PL spectra, respectively. It was revealed that a red emission could be obtained via three excitation channels, namely f–f transition of Eu3+ ions, charge‐transfer transition from O2 to Eu3+, and interband transition (IBT) of MoO6 groups. The PL spectra and their temporal decay character of Eu3+ ions depended on both crystal structure and excitation channel. The emission reduced with the crystallite size when Eu3+ ions were excited directly, but the emission evolved in a different model with the host lattices were excited. The effect of grain boundary and other lattice defect on the energy transfer and dissipation within the phosphors were discussed.