Microstructure control by Y3+ ions doping in CaMoO4:Eu3+: Tunable optical and luminescent performance

In this paper, Y 3+ ions doped CaMoO 4 :Eu 3+ with controlled microstructures were prepared via a hydrothermal method . All samples were fully characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), UV–vis diffuse reflectance spectroscopy, and photoluminescence measurement. The luminescent performance improvement aroused by doping was systematically investigated after inducing Y 3+ as co-doping ions in CaMoO 4 :Eu 3+ lattice. It is found that the lattice of Y 3+ doped CaMoO 4 :Eu 3+ nanocrystals contracted with increasing the Y 3+ concentration, resulting in a red shift of 1 A 1   →   1 T 1 transition from the valence band to the conduction band. Meanwhile, excitation band at 300   nm corresponding to the typical 1 A 1   →   1 T 1 transition also shifted to lower energy, originating from the charge-transfer between MoO 4 2− group and Eu 3+ ions. When the Y 3+ doping concentration was less than 0.05, the quantum efficiency of Y 3+ doped CaMoO 4 :Eu 3+ nanocrystals was all superior to pure CaMoO 4 :Eu 3+ nanocrystals, which can be assigned to the lattice structure contraction, co-doping effect, doping concentration variation. However, as the content of Y 3+ ions further increasing, Y 3+ ion should act as a luminescence killer, and therefore resulting in a nonradiative de-excitation.