Synthesis and photoluminescence of novel red-emitting ZnWO₄: Pr³⁺, Li⁺ phosphors

Emission enhancement in the luminescence performance of warm red light-emitting LiSrVO4 :Pr3+ phosphors

Warm red-emitting praseodymium-doped LiSrVO4 phosphors were synthesized via solid-state reaction. The phase formation was verified using an X-ray diffraction study and the morphology was investigated using a scanning electron microscope study. The LiSrVO4 :Pr3+ phosphors emitted red light when exposed to ultraviolet light, indicating their possibility for use in warm white light-emitting diodes (WLEDs). Furthermore, the effect of charge compensators on the luminescence characteristics was addressed. The decay time was investigated using time-resolved photoluminescence. Furthermore, thermal quenching was analyzed through temperature-dependent photoluminescence spectra. Their sensitivity was calculated using temperature-dependent decay time analysis. The colour purity of the emitted light could be measured by photometric analysis. This comprehensive investigation provides a thorough understanding of the luminescence properties of phosphors for WLED applications.

ZnWO4 Nanoparticle Scintillators for High Resolution X-ray Imaging

The effect of scintillator particle size on high-resolution X-ray imaging was studied using zinc tungstate (ZnWO₄) particles. The ZnWO₄ particles were fabricated through a solid-state reaction between zinc oxide and tungsten oxide at various temperatures, producing particles with average sizes of 176.4 nm, 626.7 nm, and 2.127 μm; the zinc oxide and tungsten oxide were created using anodization. The spatial resolutions of high-resolution X-ray images, obtained from utilizing the fabricated particles, were determined: particles with the average size of 176.4 nm produced the highest spatial resolution. The results demonstrate that high spatial resolution can be obtained from ZnWO₄ nanoparticle scintillators that minimize optical diffusion by having a particle size that is smaller than the emission wavelength.

Intrinsic Defect Engineering in Eu3+ Doped ZnWO₄ for Annealing Temperature Tunable Photoluminescence

Eu³⁺ doped ZnWO₄ phosphors were synthesized via the co-precipitation technique followed by subsequent thermal annealing in the range of 400–1000 °C. The phase, morphology, elemental composition, chemical states, optical absorption, and photoluminescence (PL) of the phosphors were characterized by X-ray diffraction, scanning electron microscopy, dispersive X-ray spectroscopy, X-ray photoelectron spectrometry, diffuse UV–vis reflectance spectroscopy, PL spectrophotometry, and PL lifetime spectroscopy, respectively. It is found that the PL from Eu³⁺ doped ZnWO₄ is tunable through the control of the annealing temperature. Density functional calculations and optical absorption confirm that thermal annealing created intrinsic defects in ZnWO₄ lattices play a pivotal role in the color tunable emissions of the Eu³⁺ doped ZnWO₄ phosphors. These data have demonstrated that intrinsic defect engineering in ZnWO₄ lattice is an alternative and effective strategy for tuning the emission color of Eu³⁺ doped ZnWO₄. This work shows how to harness the intrinsic defects in ZnWO₄ for the preparation of color tunable light-emitting phosphors.

Eu2+ and Eu3+ Doubly Doped ZnWO₄ Nanoplates with Superior Photocatalytic Performance for Dye Degradation

Eu²⁺ and Eu³⁺ doubly doped ZnWO₄ nanoplates with highly exposed {100} facets were synthesized via a facile hydrothermal route in the presence of surfactant cetyltrimethyl ammonium bromide. These ZnWO₄ nanoplates were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectrometry, diffuse UV-vis reflectance spectroscopy, photoluminescence spectrophotometry, and photoluminescence lifetime spectroscopy to determine their morphological, structural, chemical, and optical characteristics. It is found that Eu-doped ZnWO₄ nanoplates exhibit superior photo-oxidative capability to completely mineralize the methyl orange into CO₂ and H₂O, whereas undoped ZnWO₄ nanoparticles can only cleave the organic molecules into fragments. The superior photocatalytic performance of Eu-doped ZnWO₄ nanoplates can be attributed to the cooperative effects of crystal facet engineering and defect engineering. This is a valuable report on crystal facet engineering in combination with defect engineering for the development of highly efficient photocatalysts.

ZnWO4 nanocrystals: synthesis, morphology, photoluminescence and photocatalytic properties

The best photocatalytic properties for monoclinic ZnWO₄ nanocrystals are related to the surface energy and the types of clusters formed on their surface.