Self-assembled 3D sphere-like SrMoO4 and SrMoO4:Ln3+ (Ln=Eu, Sm, Tb, Dy) microarchitectures: Facile sonochemical synthesis and optical properties

•Sphere-like SrMoO4 micro-architectures have been synthesized by sonochemistry process.•The possible formation process of the SrMoO4 hierarchical structures was discussed.•The Ln3+-doped SrMoO4 microspheres exhibit strong light emissions with different colors.•The energy transfer process from host to rare earth ions were investigated systematically. Three-dimensional (3D) well-defined SrMoO4 and SrMoO4:Ln3+ (Ln=Eu, Sm, Tb, Dy) hierarchical structures of obvious sphere-like shape have been successfully synthesized using a large-scale and facile sonochemical route without using any catalysts or templates. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), and photoluminescence (PL) spectra were used to characterize the samples. The intrinsic structural feature of SrMoO4 and external factor, namely the ultrasonic time and the pH value, are responsible for the ultimate shape evolutions of the product. The possible formation mechanism for the product is presented. Additionally, the PL properties of SrMoO4 and SrMoO4:Ln3+ (Ln=Eu, Sm, Tb, Dy) hierarchical structures were investigated in detail. The Ln3+ ions doped SrMoO4 samples exhibit respective bright red–orange, yellow, green and white light of Eu3+, Sm3+, Tb3+ and Dy3+ under ultraviolet excitation, and have potential application in the field of color display. Simultaneously, this novel and efficient pathway could open new opportunities for further investigating about the properties of molybdate materials.