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

Abstract

In this paper, Y3+ ions doped CaMoO4:Eu3+ 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 Y3+ as co-doping ions in CaMoO4:Eu3+ lattice. It is found that the lattice of Y3+ doped CaMoO4:Eu3+ nanocrystals contracted with increasing the Y3+ concentration, resulting in a red shift of 1A1→1T1 transition from the valence band to the conduction band. Meanwhile, excitation band at 300nm corresponding to the typical 1A1→1T1 transition also shifted to lower energy, originating from the charge-transfer between MoO42− group and Eu3+ ions. When the Y3+ doping concentration was less than 0.05, the quantum efficiency of Y3+ doped CaMoO4:Eu3+ nanocrystals was all superior to pure CaMoO4:Eu3+ nanocrystals, which can be assigned to the lattice structure contraction, co-doping effect, doping concentration variation. However, as the content of Y3+ ions further increasing, Y3+ ion should act as a luminescence killer, and therefore resulting in a nonradiative de-excitation.