Synthesis and characterization of Mn2+ doped CdOZn3(PO4)2 nanocomposites

Co-Doping Effect of Mn2+ and Eu3+ on Luminescence in Strontiowhitlockite Phosphors

A new series of Sr-based phosphates, Sr9-xMnxEu(PO4)7, were synthesized using the high-temperature solid-state method in air. It was found that these compounds have the same structure as strontiowhitlockite, which is a β-Ca3(PO4)2 (or β-TCP) structure. The concentration of Mn2+ ions required to form a pure strontiowhitlockite phase was determined. An unusual partial reduction of Eu3+ to Eu2+ in air was observed and confirmed by photoluminescence (PL) and electron spin resonance (ESR) spectra measurements. The PL spectra recorded under 370 nm excitation showed transitions of both 4f5d-4f Eu2+ and 4f-4f Eu3+. The total integral intensity of the PL spectra, monitored at 395 nm, decreased with increasing Mn2+ concentration due to quenching effect of Eu3+ by the Mn2+ levels. The temperature dependence of Eu2+ photoluminescence in a Sr9-xMnxEu(PO4)7 host was investigated. The conditions for the reduction of Eu3+ to Eu2+ in air were discussed.

Photoconductive and Antimicrobial Properties of Psidium guajava Leaf Extract Mediated Green Synthesized SnS2–CdO and SnS2–NiO Nanocomposites

This paper reports the photoconductive and antimicrobial properties of SnS2–CdO and SnS2-NiO nanocomposites green synthesized using Psidium guajava leaf extract. X-ray diffraction studies reveal that the SnS2–CdO nanocomposite exhibits hexagonal SnS2 and cubic CdO diffraction peaks; whereas the SnS2–NiO nanocomposite exhibits hexagonal SnS2 and cubic NiO diffraction peaks. SEM image of the bio-synthesized SnS2–CdO nanocomposite confirmed nanoneedles with grains being well distributed. Regular shaped grains with decreased sizes were observed for the SnS2–NiO nanocomposite. Nanosized grains were observed from the TEM images. The existence of elements Sn, S, Cd, O in SnS2–CdO nanocomposite; Sn, S, Ni, O in SnS2–NiO nanocomposite was confirmed from the EDX and XPS spectra. Increased photosensitivity value was realized for the SnS2–CdO nanocomposite. Both the composites showed good fungal inhibition property against Aspergillus terreus fungi not only by the physical, chemical and biological processes but also owing to phyto-constituents in the leaf extract.