The Ce3+-Tb3+ doped CaSi2O2N2 phosphors are successfully obtained via conventional solid-state reaction at normal pressure. Broad absorption bands from Ce3+ are clearly observed in the excitation spectra of CaSi2O2N2:Tb3+, Ce3+. The emission spectra present a combination of Tb3+ and Ce3+ emission bands, and the emission intensity of Ce3+ is decreased along with the enhancement of the emission intensity of Tb3+. The energy transfer from Ce3+ to Tb3+ in the CaSi2O2N2 host is confirmed to be resonant type via a dipole–dipole interaction mechanism. It is also found that the luminescence intensity of the Tb3+-Ce3+ doped CaSi2O2N2 phosphors prepared in N2/H2 atmosphere is stronger than that prepared in pure N2.

Graphitic carbon nitride (g-C3N4) was deposited onto TiO2 nanotube arrays (TNTAs) by a simple impregnation method to afford a Z-scheme g-C3N4/TNTAs photocatalytic system. The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectrum, and X-ray photoelectron spectroscopy (XPS). The g-C3N4/TNTAs exhibit improved efficiency for photodegradation of Rh B under visible light irradiation comparing with bare TiO2 nanotube arrays, and CN(10)/TNTAs prepared by 10 times impregnation show the highest activity. The enhanced visible light photocatalytic activity is attributed to the optimized light absorption and effective separation of photogenerated electrons and holes. This article demonstrates a simple way to prepare the Z-scheme heterogeneous photocatalyst with improved performance for potential application in environmental control.

Thin films of Au-CuO plasmonic nanohybrids were fabricated by simple thermal evaporation. SEM and XRD investigations unveiled the impact of annealing on the structural properties and morphology of the synthesized Au-CuO hybrid thin film. Au nanoparticle decoration onto CuO thin film significantly altered the photocatalytic activity, structural and optical properties of CuO thin film. The as-prepared Au-CuO nanostructured hybrid plasmonic thin film showed improved photocatalytic efficiency for decomposition of MG and MB than pristine CuO and annealed Au-CuO thin film samples. The improved photocatalytic efficiency of Au-CuO hybrid nanostructured thin film is attributed to reduction in the recombination of charge carriers in CuO nanostructures and improvement in light utilization capability due to attachment of Au nanoparticles on nanostructured CuO thin film. Cracks in Au-CuO nanohybrid thin film facilitated enhanced adsorption of dye molecules and played an essential role in improving the photocatalytic efficiency.

Ge1-xMnxTe-based IV-VI ferromagnetic semiconductors are attractive due to their versatile material properties. In this study, we investigate the physical properties of Ge1-xMnxTe with xMn ≤ 0.50 using density functional theory. The dominant exchange splitting caused by pd-hybridisation mediates ferromagnetism that is consistent with the stable ferromagnetic (FM) states, as observed using structural optimisations. The presence of holes due to the half-metallic character suggests that RKKY interactions stabilise FM states. The absorption edges lie in the infrared energy range and are influenced by the crystal symmetry, and the compounds exhibit strong absorption of visible and UV energies. The narrow band gaps extracted from the band structures and the Tauc plots show similar variations with the Mn content, and hence suggest applications in optoelectronic devices.

ZnO decorated rGO nanocomposites (ZnO∙x% rGO NC (x = 1, 5, 10, 15, 20 and 25)) were fabricated using hydrothermal method. Elemental mapping of Zn ions on the surface of ZnO∙rGO were distributed over the surface. SEM images showed that ZnO nanoparticles have agglomerated into micron size clusters. EDS measurements were used to determine the exact chemical content of NC’s. FTIR spectra indicated that GO had been reduced to rGO by hydrothermal fabrication process used. The shifts of G band in Raman spectra indicate the presence of interfacial Zn-O-C bonds. UV-Vis absorption studies were used to monitor the amount of Cr6+ ions in solutions after their exposure to light. Photocatalytic reduction of toxic Cr6+ was observed by time change in the absorption of light at two wave lengths, 273 nm and 373 nm. The enhancement of photo reduction rate increased, reaching a maximum at x = 10% and then decreased.