As a non-metallic organic semiconductor, graphitic carbon nitride (g-C₃N₄) has received much attention due to its unique physicochemical properties. However, the photocatalytic activity of this semiconductor faces challenges due to factors such as low electronic conductivity and limited active sites provided on its surface. The morphology and structure of g-C₃N₄, including macro/micro morphology, crystal structure and electronic structure can affect its catalytic activity. Non-metallic heteroatom doping is considered as an effective method to tune the optical, electronic and other physicochemical properties of g-C₃N₄. Here, we synthesized non-metal-doped highly crystalline g-C₃N₄ by one-pot calcination method, which enhanced the photocatalytic activity of g-C₃N₄ such as mesoporous nature, reduced band gap, wide-range photousability, improved charge carrier recombination, and the electrical conductivity was improved. Hence, the use of low-power white-LED-light illumination (λ ≥ 420 nm) and ultrasound (US) irradiation synergistically engendered the Methylene Blue (MB) mineralization efficiency elevated to 100% within 120 min by following the pseudo-first-order mechanism under the following condition (i.e., pH 11, 0.75 g L⁻¹ of O-doped g-C₃N₄ and S-doped g-C₃N₄, 20 mg L⁻¹ MB, 0.25 ml s⁻¹ O₂, and spontaneous raising temperature). In addition, the rapid removal of MB by sonophotocatalysis was 4 times higher than that of primary photocatalysis. And radical scavenging experiments showed that the maximum distribution of active species corresponds to superoxide radical $${\mathrm{O}}_{2}^{\cdot-}$$O 2 · - . More importantly, the sonophotocatalytic degradation ability of O-doped g-C₃N₄ and S-doped g-C₃N₄ was remarkably sustained even after the sixth consecutive run.

Thermo-optical characteristics of a new magneto-active material, ${\mathrm{Na}}_{0.37}{\mathrm{Tb}}_{0.63}{\mathrm{F}}_{2.26}$ crystal, were investigated in this Letter. This crystal has a high value of magneto-optical figure-of-merit and negative optical anisotropy parameter that makes it a promising material for development of Faraday isolators for high-power lasers; in particular it gives opportunities for the realization of new schemes of optical isolators.

Homogeneous crystals of Ca0.59Sr0.41F2 alloy (sp. gr., Fm$$ \bar 3 $$m, a = 0.56057 nm), corresponding to the point of minimum in the melting curve in the CaF2-SrF2 phase diagram, have been grown by t

Photopolymerization of nanocomposite materials using near infrared light is one of the unique technologies based on the luminescent properties of lanthanide-doped upconversion nanoparticles (UCNPs). We explored the UCNP-triggered radical polymerization both in oligomer bulk and on the nanoparticle surface in aqueous dispersion. Core/shell UCNPs NaYF₄:Yb³⁺ and Tm³⁺/NaYF₄ with emitting lines in the ultraviolet and blue regions were used to activate a photoinitiator. The study of the bulk photopolymerization in an initially homogeneous reaction mixture showed the UCNP redistribution due to gradient density occurring in the volume, which led to formation of UCNP superlattices and spheres “frozen” in a polymer matrix. We also developed a strategy of “grafting from” the surface, providing polymer shell growth directly on the nanoparticles. The photosensitization of the endogenous water-soluble photoinitiator riboflavin by the resonance energy transfer from UCNPs was demonstrated in the course of monomer glycidyl methacrylate polymerization followed by photocrosslinking with poly(ethylene glycol) diacrylate on the nanoparticle surface.

Crystals of nonstoichiometric phases Sr_{1 − x} R _x F_{2 + x} (R are 14 rare-earth elements) and the ordered phase Sr₄Lu₃F₁₇ with a trigonally distorted fluorite lattice were grown by the Bridgman method. Ten of 26 Sr_{1 − x} R _x F_{2 + x} crystals, where R = La-Ho or Y, melt congruently. The isoconcentration series Sr_0.90 R _0.10F_2.10 includes four crystals with R = Er-Lu. The compositions corresponding to the maxima for the latter crystals were not determined. The concentration series, in which the mole fraction of RF₃ varies from 10 to 50 mol %, were obtained for the crystals with R = La, Nd, and Gd. Most of the crystals are of good optical quality. To evaluate the composition changes in the course of crystal growth, the cubic unit-cell parameters were determined by X-ray powder diffraction. The line-broadening analysis revealed a nonmonotonic change of microdistortions as regards both the rare-earth content and rare-earth series. The changes in the lattice parameters and the congruent-melting points of the Sr_{1 − x} R _x F_{2 + x} phases in the rare-earth series reflect the morphotropic transitions in the series of pure RF₃ despite the fact that SrF₂ dominates in nonstoichiometric fluorite crystals.