Sono-Chemical Synthesis of Silver Quantum Dots Immobilized on Exfoliated Graphitic Carbon Nitride Nanostructures Using Ginseng Extract for Photocatalytic Hydrogen Evolution, Dye Degradation, and Antimicrobial Studies.

Due to modernization and the scarcity of fossil fuel resources, energy demand is continuously increasing. In this regard, it is essential and necessary to create a renewable energy source that can meet future energy demands. Recently, the production of H2 by water splitting and removing pollutants from the water has been essential for issues of energy and environmental demands. Herein, g-C3N4 and Ag-g-C3N4 composite structures have been successfully fabricated by the ultrasonication method. The physio/photochemical properties of prepared g-C3N4 and Ag-g-C3N4 were examined with different analytical techniques such as FTIR, XRD, UV-DRS, SEM, TEM, PL, and XPS analyses. The silver quantum dots (QDS) anchored to g-C3N4 structures performed the profound photocatalytic activities of H2 production, dye degradation, and antimicrobial activity under visible-light irradiation. The Ag/g-C3N4 composite with an Ag loading of 0.02 mole has an optimum photoactivity at 335.40 µmol g-1 h-1, which is superior to other Ag loading g-C3N4 composites. The synthesized Ag/g-C3N4 nanoparticles showed potential microbial inhibition activity during the preliminary screening, and the inhibition zones were comparable to the commercial antibiotic chloramphenicol. The loading of Ag into g-C3N4 paves the suppression, recombination and transfer of photo-generated electron-hole pairs, leading to the enhancement of hydrogen production, the diminishment of pollutants in water under visible light irradiation, and antimicrobial activity against multidrug-resistant pathogens.

Synthesis and luminescence properties of Pr3+ ion-doped Ba3 Y(PO4 )3 phosphors.

Barium yttrium phosphate (BYP) phosphor doped with trivalent praseodymium ions (BaY(1-x) (PO4 )3 :Pr3+ (x = 0, 0.01, 0.05, 0.1, 0.15, and 0.2 wt%) was synthesized using a high temperature solid-state reaction method. Structural properties were analyzed through X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. XRD patterns confirmed the structure of the synthesized phosphor and average crystalline size was estimated (approximately 63.8 Å). Vibrational functional groups were identified using FTIR spectroscopy. The emission spectrum was recorded under an 444 nm excitation wavelength, which showed various emission transitions of Pr3+ ions. Commission Internationale de l'éclairage coordinates, colour purity, and colour correlated temperature values were calculated for the BYP:Pr3+ phosphors and these coordinate values fell in the yellow region of the visible spectrum.

Study of trivalent samarium ion embedded lithium-based borate glass for high-density optical memory devices.

Sm3+ ions doped strontium lithium lead borate glasses (SLLB:Sm) were prepared using a conventional melt-quenching technique. The glasses were analyzed using X-ray diffractometry and Fourier transform infrared spectroscopy, optical absorption, fluorescence spectral analysis, and fluorescence lifetime decay. The Judd-Ofelt (J-O) parameters and radiative parameters of the SLLB:Sm10 glass (1.0 mol% Sm3+ ion-doped glass) were calculated using J-O theory. From the emission spectra, among all the synthesized glass, SLLB:Sm10 glass had the highest emission intensity for 4 G5/2 →6 H11/2 transition (610 nm). Emission parameters, such as stimulated emission cross-section and optical gain bandwidth, were calculated. For all concentrations of Sm3+ ions, the decay profile showed an exponential nature and decreased when the Sm3+ ion concentration was increased due to a concentration quenching effect. This result suggests that the synthesized SLLB:Sm10 glass could be used for application in high-density optical memory devices.