Red emission enhancement in BaYF:Eu phosphor nanoparticles by Bi co-doping.

Herein, we report the photoluminescence properties of Bi-sensitized BaYF5:10 mol%Eu nanoparticles. The emission spectra feature Eu peaks corresponding to transitions from the D0 excited to FJ (J = 1, 2, 3, 4) lower levels with two dominant emissions positioned in the orange-red (∼ 592 nm, D0 → F1) and deep-red (∼ 697 nm, D0 → F4) regions. Upon 265 nm excitation, the emission intensity increases with an increase of Bi concentration up to 20 mol%.

Tuneable Red and Blue Emission of Bi-Co-Doped SrF:Eu Nanophosphors for LEDs in Agricultural Applications.

Tunable blue/red dual-emitting Eu-doped, Bi-sensitized SrF phosphors were synthesized utilizing a solvothermal-microwave method. All phosphors have cubic structure (- (225) space group) and well-distinct sphere-like particles with a size of ~20 nm, as examined by X-ray diffraction and transmission electron microscopy. The diffuse reflectance spectra reveal a redshift of the absorption band in the UV region as the Bi concentration in SrF: Eu phosphor increases.

Hydrothermal Synthesis and Properties of Yb/Tm Doped SrLaF Upconversion Nanoparticles.

We report the procedure for hydrothermal synthesis of ultrasmall Yb/Tm co-doped SrLaF (SLF) upconversion phosphors. These phosphors were synthesized by varying the concentrations of Yb (x = 10, 15, 20, and 25 mol%) and Tm (y = 0.75, 1, 2, and 3 mol%) with the aim to analyze their emissions in the near IR spectral range.

Organic solvent-assisted co-precipitation synthesis of red-emitting KTiF:Mn phosphors with improved quantum efficiency and optimized morphology.

We report an organic solvent-assisted (OSA) co-precipitation strategy for the production of Mn-activated KTiF phosphor. The phosphor particle size was controlled through the selection of organic solvents with an alcohol functional group and different carbon chain lengths used in the synthesis. The synergistic effect of the organic solvent and hydrofluoric acid results in large smoothed hexagonal-shaped crystal sheets of particles that become larger as the carbon chain length of the organic solvent increases.

Single-Crystal Red Phosphors and Their Core-Shell Structure for Improved Water-Resistance for Laser Diodes Applications.

A solvent-vapor transport route produces centimeter-sized single-crystal red phosphors. The epitaxial growth route to yield its core-shell structure at ambient temperature was adopted. These red phosphors could be applied in all-inorganic WLED devices.

Characterization of cereal flours by fluorescence spectroscopy coupled with PARAFAC.

This paper presents parallel factor analysis (PARAFAC) of fluorescence of cereal flours. Excitation-emission matrices (EEM's) of different cereal flours (wheat, corn, rye, rice, oat, spelt, barley and buckwheat) were measured in a front-face configuration over the ultraviolet-visible spectral range. EEM's showed that flours strongly fluoresce in two spectral regions, where amino acids, tocopherols, pyridoxine and 4-aminobenzoic acid show intense emissions.

Genetic Polymorphisms of Catechol-O-Methyltransferase: Association with Temporomandibular Disorders and Postoperative Pain.

Aims: To evaluate the association between catechol-O-methyltransferase (COMT) gene polymorphisms and temporomandibular disorders (TMD), TMD pain, psychosocial impairment related to TMD, and postoperative pain.

Methods: A total of 90 patients with a diagnosis of painful TMD and 92 matched controls were investigated for the presence of TMD, TMD pain, and psychosocial variables by the Research Diagnostic Criteria for TMD. In a prospective cohort study of 40 subjects who underwent extraction of at least one fully impacted mandibular third molar, subjects had 6 months post-surgery follow-up of postoperative pain.

Changes of Color and Fluorescence of Resin Composites Immersed in Beer.

Objective: The aim of this study was to evaluate changes of color and fluorescence of resin based composite exposed to beer.

Materials And Methods: 84 samples (13 mm in diameter and 1.5 mm thick) of microhybrid composite Gradia Direct extra bleach white were immersed in 5 different beers (dark and light) or distilled water.