Controllable synthesis of multi-morphological SrWO4:Ln3+ (Ln = Eu, Tb) hierarchical structures and their luminescence properties†
Multi-morphological Ln3+ (Ln = Eu, Tb) doped SrWO4 hierarchical structures were successfully synthesized via a hydrothermal method. The phase structure, morphology and luminescence properties of the as-prepared samples were characterized by XRD, SEM, TEM, PL spectroscopy and lifetime measurements. The results indicate that the alteration of synthesis conditions has almost no effect on the phase structure, but has a prominent effect on the morphology of the obtained samples, such as the molar ratio of Sr2+ to WO42− from 1 : 3 to 6 : 1 (split spheres, dumbbell-like, rod-like, nanosheets), addition of Na3C6H5O7·2H2O from 0.1 to 0.5 g (microspheres, rice-like), addition of Na2EDTA·2H2O from 0.01 to 0.3 g (spheres, split spheres, peanut-like, drum-like, ellipsoidal morphology), and the doping concentration of Eu3+ ions from 1% to 16% (dumbbell-like, rod-like). The as-synthesized SrWO4:Ln3+ (Ln = Eu, Tb) samples with various morphologies have an identical scheelite structure and exhibit the characteristic visible emission of the dopant rare earth ions under the excitation of UV light.