Self-assembled 3D flower-shaped NaY(WO4)2:Eu3+ microarchitectures: Microwave-assisted hydrothermal synthesis, growth mechanism and luminescent properties

Abstract

Three dimensional (3D) flower-shaped microarchitectures of NaY(WO₄)₂ were synthesized via a microwave-assisted hydrothermal process in the presence of trisodium citrate (Na₃Cit) and a post-calcination process. The effects of reaction conditions on the morphology of precursor microstructures were studied. It was found that Na₃Cit, as the chelating agent and shape modifier, plays a key role in the microstructure growth. A possible growth mechanism for the flower-shaped microarchitectures was proposed. The as-formed precursor can completely transform into NaY(WO₄)₂ with its original flower-shaped morphology via a heat treatment process. The concentration and temperature quenching behaviors of Eu³⁺ fluorescence in the flower-shaped NaY(WO₄)₂ were studied, and the optimal doping concentration was confirmed, meanwhile the activation energy was obtained. Judd-Ofelt parameters Ω_λ (λ = 2, 4 and 6) of Eu³⁺ in the flower-shaped NaY(WO₄)₂ phosphor were obtained by using the emission spectrum of Eu³⁺, moreover the radiative transition properties were analyzed.