Optical Information Transmission and Multimode Fluorescence Anticounterfeiting of Ca2-xMgxGe7O16:Mn2.

Multimode emission of Mn2+ for multimode fluorescence anticounterfeiting is achieved by cation site and interstitial occupancy in Ca2-xMgxGe7O16. The rings in Ca2-xMgxGe7O16 have a significant distortion for Mn2+ ions to enter the ring interstitials with a luminescence center at 665 nm, which is supported by XRD refinement results and first-principles calculations. The interstitial Mn2+ ion has good thermal stability with an activation energy of 0.36 eV. Surprisingly, these two luminescence centers, the cation site Mn and the interstitial Mn, have an obvious afterglow, and the disappearing afterglow will reappear by heating or irradiating with the 980 nm laser. The afterglow is significantly enhanced, as MnO2 is used as the manganese source, which is explained in detail by the thermal luminescence spectrum. Finally, Ca2-xMgxGe7O16:Mn2+ fully demonstrates its excellent prospects in fluorescent anticounterfeiting, information encryption, and optical information storage.

Parallel Structure Enhanced Polysilylaryl-enyne/Ca0.9La0.067TiO3 Composites with Ultra-High Dielectric Constant and Thermal Conductivity.

With the rapid development of the microwave communication industry, microwave dielectric materials have been widely studied as the medium of signal transmission. Nowadays, with the increase in communication frequency, devices are miniaturized, and dielectric materials are required to have higher dielectric constants. At the same time, the miniaturization of devices brings about an increase in power density, which puts forward higher requirements for the thermal conductivity of materials. In this work, polysilylaryl-enyne (PSAE) and Ca0.9La0.067TiO3 (CLT) were chosen as the matrix and filler, respectively, to construct a parallel model composite through a freeze casting method and a 0-3 model composite through the direct mixing method, respectively. After comparing the microstructures of the two models, their dielectric properties and thermal conductivity were measured and simulated. The parallel model composites in the stable range possess uniform parallel structures, and the solid content limit for them could be as high as 73.2%, which is much higher than that of the 0-3 model composites. While the 0-3 model composite possesses an optimal dielectric constant of 25.4 (@10 GHz) and a thermal conductivity of 0.965 W·m-1·K-1, the parallel model composite possesses a 2 times higher dielectric constant of 76.2 (@10 GHz) and a 1 times higher thermal conductivity of 2.095 W·m-1·K-1. Since the parallel model composite possesses much higher dielectric constant and thermal conductivity than traditional 0-3 model composites, it can be an excellent candidate for microwave communication.

Oxygen-vacancy-rich BiOCl materials with ultrahigh photocatalytic efficiency by etching bismuth glass.

Bismuth oxychloride (BiOCl) is a promising photocatalyst material for water purification to remove organic pollutants. However, BiOCl materials can only degrade pollutants under ultraviolet-light owing to their wide band gap. Herein, we propose a simple synthesis route based on Bi2O3-B2O3-ZnO-SrO-Na2O (BBZSN) glass to fabricate 3D hierarchical-structured BiOCl materials with rich oxygen vacancies (OVs), which were introduced from BBZSN glass and inhibited the recombination of electron-hole pairs and adjusted the band structure. The photocatalytic activity of the obtained 3D hierarchical-structured BiOCl photocatalyst was evaluated by the degradation of Rhodamine B (RhB) under ultraviolet light and visible light. The experimental results suggested that the as-fabricated flower-shape BiOCl-NaCl could effectively degrade RhB under ultraviolet light (92.7%/20 min) or visible light (71.4%/20 min, 92.8%/100 min) respectively, which indicates its potential to be applied in environmental remediation.