## 1 Introduction  
Inorganic oxide luminescence materials have practical applications in many different devices for artificial light production. For example, a red phosphor is helpful to generate white light LEDs under the excitation of blue or near-UV (NUV) LEDs. The dopant europium (Eu\({}^{2+}\) or Eu\({}^{3+}\)) ions exhibit very interesting photoluminescence properties in different oxidation states. The Eu\({}^{2+}\) ion shows a 5d-4f transition, and this transition can cause the phosphors to vary from ultraviolet to yellow emissions. Europium in the trivalent (Eu\({}^{3+}\)) state gives red (\({}^{5}\)D\({}_{0}\)\(\rightarrow\)\({}^{7}\)F\({}_{2}\) transition) or reddish-orange emissions (\({}^{5}\)D\({}_{0}\)\(\rightarrow\)\({}^{7}\)F\({}_{1}\) transition) as reported in different Eu\({}^{3+}\)-doped oxides, for example in host borates [1] and tungstates [2], respectively. [PERSON] _et al._ had reported that as the multiplex compound of halides and borates of the Ca\({}_{2}\)BO\({}_{3}\)Cl:Eu\({}^{2+}\) composition is synthesized by the solution combustion method, this composition emits blue and yellow emissions to form a bright yellow emission [3]. [PERSON] _et al._ also found that the novel Ca\({}_{2}\)B\({}_{5}\)O\({}_{9}\)Br:Eu\({}^{2+}\) phosphor would have a blue emission when it was prepared by the microwave method, and the novel Ca\({}_{2}\)B\({}_{5}\)O\({}_{9}\)Br:Eu\({}^{2+}\) phosphor had been proved to be the promising phosphor for white light-emitting diodes [4]. Eu-doped oxide phosphors have also been intensively studied due to their intense sharp red emission centered at around 611 nm, which is emits a red color and is one of the three primary colors. For example, [PERSON] _et al._ found that YGdBO\({}_{3}\) doped with Eu would generate emissions at 367, 454, 595, 611, and 628 nm, and the intensity of peak at 366 nm is relatively less as compared to 594, 613 and 629 nm peaks [5]. Alkaline earth zirconates can be used to form the compounds with the general formula \(A^{2+}B^{4+}\)O\({}_{3}\) (where \(A\) = Ca, Pb, Sr, Ba; \(B\) = Ti, Zr) having perovskite-type structure. Recently, more and more research has been focused on the luminescent properties of rare earth ion-doped \(AB\)O\({}_{3}\) perovskite-based oxides, because perovskite-based phosphors are very stable and they can steadily work in various environments, and that is a merit for the phosphors' application. In the formula of \(A^{2+}B^{4+}\)O\({}_{3}\) compositions, BaZrO\({}_{3}\) ceramic has a perovskite structure and it can be doped easily by divalent or trivalent rare earth ions; it also possesses many good properties such as high refractive index, wide energy band gap, low optical loss, chemical and photo-chemical stability and excellent mechanical, electrical, thermal and optical properties, and perfect single-phase structure [6,7]. Different rare earth-doped BaZrO\({}_{3}\) powders can be applied as a new class of luminescence materials. BaZrO\({}_{3}\)-based powders are known for their outstanding properties such as high thermal and chemical stability and easily forming the single crystalline phase by using the solid-state reaction method. Eu\({}^{3+}\)-doped BaZrO\({}_{3}\) phosphors also show the merits of brightness and flexible industrial processing ability, and they are suitable for lighting and display devices. As such, more and more investigations are focused on luminescent properties and mechanisms of rare earth ion-doped BaZrO\({}_{3}\)[8], in which Yb\({}^{3+}\)[9], Tm\({}^{3+}\)[9], Eu\({}^{3+}\)[10,11], Ti\({}^{+4}\)[11], and Tb\({}^{3+}\)[12] have been developed as dopants in BaZrO\({}_{3}\) powder, and their luminescent properties and corresponding mechanisms were discussed. [PERSON] _et al._ found that \(\beta\)-SiAlON:Eu phosphor powders exhibit a typical rod-like morphology. The low Eu\({}^{2+}\) concentrations would cause the \(\beta\)-SiAlON:Eu phosphors to have a blue emission and the high Eu\({}^{2+}\)-doping concentrations would cause the \(\beta\)-SiAlON:Eu phosphors to have a green emission [13].