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Uniform single-crystalline NaLa(WO4)2 microspindles were successfully prepared via a hydrothermal method in combination with a post annealing process by adding an extremely small amount of EDTA-2Na into the reaction system. Meanwhile, the product morphology could also be tuned into microplates, nanocrystals, submicrodumbbells and connected twin-microspheres by simply altering the amount of additive used and the ratio of the mixed solvents. The prepared NaLa(WO4)2 nanocrystals could be homogeneously dispersed in the distilled water for a very long time, and thus might find potential application in the field of biological labeling. The photoluminescent (PL) performance of the NaLa(WO4)2 : Eu3+ microspindles and microplates was investigated and it was found that the NaLa(WO4)2 : Eu3+ microspindles had a much more intensive emission, and furthermore, the possible reasons responsible for the improved photoluminescent performance of the microspindles were discussed. More importantly, due to the efficient energy transfer from Tm3+, Tb3+ to Eu3+, a novel single-phased and near-UV-pumped white-light-emitting phosphor NaLa(WO4)2 : Eu3+/Tb3+/Tm3+ was also successfully fabricated through optimizing the molar ratio among Eu3+, Tb3+ and Tm3+ in the NaLa(WO4)2 microspindle host. This NaLa(WO4)2 : Eu3+/Tb3+/Tm3+ microspindle phosphor might be promising in the field of near-UV-pumped white LEDs. [ABSTRACT FROM AUTHOR]

Bi2WO6with multilayered disc-like and 3D hierarchical nest-like architectures self-assembled from 2D nanosheets were successfully synthesized by a hydrothermal method in EDTA-mediated processes. It was found that the morphology modulation of the as-obtained products could be easily realized simply by changing the amount of EDTA introduced into the reaction system. The stepwise self-assembly formation mechanisms for two different hierarchical architectures were proposed on the basis of a series of time-dependent experiments. The photocatalytic activities of the different Bi2WO6samples for the degradation of Rhodamine B (RhB) were also evaluated. Due to the unique morphology, porous structure and large surface area, Bi2WO6nest-like architectures exhibited better activity performance than Bi2WO6multilayered microdiscs. The present work not only presents an efficient way for the selectively controllable preparation of Bi2WO6hierarchical structures viaself-assembly from 2D nanosheets, but also provides a step forward in the design of photocatalysts with controllable morphology and enhanced photocatalytic activities. [ABSTRACT FROM AUTHOR]

Tetragonal NaEu(MoO4)2with rugby-like microstructures were successfully synthesized by a hydrothermal method in an EDTA-mediated process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) techniques were employed to characterize the products in detail. It was found that the amount of EDTA, reaction temperature and pH value are important parameters affecting the morphology, crystallinity and size of the final product, respectively. The possible formation mechanism for the microrugbies was proposed on the basis of a series of time-dependent experiments. This facile method was also successfully applied in the synthesis of NaSm(MoO4)2and NaGd(MoO4)2microrugbies. The photoluminescence (PL) properties of NaEu(MoO4)2microrugbies were strongly dependent on the size and crystallinity. The calcined products displayed excellent luminescence behaviors with a high color purity and have the potential to be applied in LED devices. The possible reasons for the difference in the relative intensities of luminescence are also discussed in detail. [ABSTRACT FROM AUTHOR]

Uniform single-crystalline NaLa(WO4)2 microspindles were successfully prepared via a hydrothermal method in combination with a post annealing process by adding an extremely small amount of EDTA-2Na into the reaction system. Meanwhile, the product morphology could also be tuned into microplates, nanocrystals, submicrodumbbells and connected twin-microspheres by simply altering the amount of additive used and the ratio of the mixed solvents. The prepared NaLa(WO4)2 nanocrystals could be homogeneously dispersed in the distilled water for a very long time, and thus might find potential application in the field of biological labeling. The photoluminescent (PL) performance of the NaLa(WO4)2 : Eu3+ microspindles and microplates was investigated and it was found that the NaLa(WO4)2 : Eu3+ microspindles had a much more intensive emission, and furthermore, the possible reasons responsible for the improved photoluminescent performance of the microspindles were discussed. More importantly, due to the efficient energy transfer from Tm3+, Tb3+ to Eu3+, a novel single-phased and near-UV-pumped white-light-emitting phosphor NaLa(WO4)2 : Eu3+/Tb3+/Tm3+ was also successfully fabricated through optimizing the molar ratio among Eu3+, Tb3+ and Tm3+ in the NaLa(WO4)2 microspindle host. This NaLa(WO4)2 : Eu3+/Tb3+/Tm3+ microspindle phosphor might be promising in the field of near-UV-pumped white LEDs. [ABSTRACT FROM AUTHOR]