Surfactant-Assisted Hydrothermal Synthesis of Eu³⁺-Doped White Light Hydroxyl Sodium Yttrium Tungstate Microspheres and Their Conversion to NaY(WO₄)₂

Abstract

In this work, large-scale three-dimensional "flake-ball" microarchitectures of Eu(3+) doped white light hydroxyl sodium yttrium tungstate were prepared by the well-known hydrothermal approach at 180 degrees C for 48 h in the presence of triblock-copolymer poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (P123). NaY(WO(4))(2):Eu(3+) phosphor was formed by annealing the hydrothermal product at approximately 630 degrees C for 2 h. A time-dependent microstructure evolution study was performed under hydrothermal reaction. The evolution process is the self-assembly process of P123, and the effects of other reaction parameters, such as influence of the concentration of P123 on morphology, and the influence of temperature on PL. The mechanism by which the "flake-ball" particles are formed is discussed in detail. The PL spectra of Eu(3+)-doped hydroxyl sodium yttrium tungstate phosphor contain two parts: the broad blue-green band and the (5)D(0)-->(7)F(J) (J = 1, and 2) characteristic transition of Eu(3+). This approach provides a facile route for the production of high-quality hydroxyl sodium yttrium tungstate microstructures with an interesting optical property.