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La2(MoO4)3 phosphors with various Eu3+ concentrations were prepared via a facile co-precipitation process. The crystal structure and morphology of the phosphors were characterized by means of XRD and field emission scanning electron microscope. The crystal unit cell parameters a, b, and c for the monoclinic phase La2(MoO4)3 were calculated to be 16.989, 11.927, and 16.086 Å, respectively. The average size of the phosphor particles was estimated to be around 88.5 nm. The Huang–Rhys factor was derived from the phonon sideband spectra to be 0.073. The self-generated quenching process of Eu3+ was explained based on Auzel’s model, and the intrinsic radiative transition lifetime for 5D0 level was confirmed to be 0.99 ms. A new approach for calculating the Judd–Ofelt parameters was developed, meanwhile the Judd–Ofelt parameters Ωλ (λ = 2, 4, 6) of Eu3+ in La2(MoO4)3 phosphors were confirmed to be 10.70 × 10−20, 1.07 × 10−20, and 0.56 × 10−20 cm2, respectively. Finally, the optimal doping concentration for achieving maximum emission intensity was confirmed to be 17 mol. % by analyzing the concentration quenching.

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Three dimensional (3D) flower-shaped microarchitectures of NaY(WO 4 ) 2 were synthesized via a microwave-assisted hydrothermal process in the presence of trisodium citrate (Na 3 Cit) and a postcalcination process. The effects of reaction conditions on the morphology of precursor microstructures were studied. It was found that Na 3 Cit, 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(WO 4 ) 2 with its original flowershaped morphology via a heat treatment process. The concentration and temperature quenching behaviors of Eu 3+ fluorescence in the flower-shaped NaY(WO 4 ) 2 were studied, and the optimal doping concentration was confirmed, meanwhile the activation energy was obtained. Judd-Ofelt parameters U l (l ¼ 2, 4 and 6) of Eu 3+ in the flower-shaped NaY(WO 4 ) 2 phosphor were obtained by using the emission spectrum of Eu 3+ , moreover the radiative transition properties were analyzed.

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