Calcium Tungstate Doped with Rare Earth Ions Synthesized at Low Temperatures for Photoactive Composite and Anti-Counterfeiting Applications

Optical analysis of RE3+ (RE = Eu,Tb):MgLa2 V2 O9 nano-phosphors

Red and green rare-earth ion (RE3+ ) (RE = Eu, Tb):MgLa2 V2 O9 micro-powder phosphors were produced utilizing a standard solid-state chemical process. The X-ray diffraction examination performed on the phosphors showed that they were crystalline and had a monoclinic structure. The particles grouped together, as shown in the scanning electron microscopy (SEM) images. Powder phosphors were examined using a variety of spectroscopic techniques, including photoluminescence (PL), Fourier-transform infrared, and energy dispersive X-ray spectroscopy. Brilliant red emission at 615 nm (5 D0  → 7 F2 ) having an excitation wavelength (λexci ) of 396 nm (7 F0  → 5 L6 ) and green emission at 545 nm (5 D4  → 7 F5 ) having an λexci  = 316 nm (5 D4  → 7 F2 ) have both been seen in the emission spectra of Tb3+ :MgLa2 V2 O9 nano-phosphors. The emission mechanism that is raised in Eu3+ :MgLa2 V2 O9 and Tb3+ :MgLa2 V2 O9 powder phosphors has been explained in an energy level diagram.

Development of novel microsphere structured - calcium tungstate as efficacious electrocatalyst for the detection of antibiotic drug nitrofurantoin

In this report, synthetic and nitro groups containing antibiotic drug nitrofurantoin (NFT) were electrochemically quantified under amended conditions using novel constructed calcium tungstate microspheres modified on glassy carbon electrodes (CTMs/GCE). The calcium tungstate microspheres (CTMs) were synthesized by a facile sonochemical method and characterizations were done by various techniques, such as X-ray diffraction spectrometry (XRD), Fourier transform infrared spectroscopy (FTIR), Raman, field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Ahead of this, electrochemical investigations were performed using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), amperometry, and linear sweep voltammetry (LSV). The synthesis of CTMs as well-distributed microspheres allows more active metal sites regarding and remarkable electrocatalytic activity towards NFT detection with excellent sensitivity (0.724 μA μM-1 cm-2) and low detection limit (21 nmol L-1) with a wide linear range 10-140 μM. The practical feasibility of the developed CTMs/GC electrode was elucidated using distinct real sample river tap water and clinical sample (NFT capsule), and thus, the modified electrode manifested acceptable recovery results.

Synthesis of Rare-Earth-Doped Strontium Tungstate Phosphor at Room Temperature and Applied Flexible Composite

In this study, we successfully synthesized rare-earth-doped crystalline SrWO₄ at room temperature by co-precipitation. The results from the X-ray diffraction analysis showed a main diffraction peak related to the (112) plane. Phosphors doped with either Dy³⁺ or Sm³⁺ ions showed strong light absorption in the UV region and blue-yellow and red light emission. To synthesize a white light phosphor, Dy³⁺ and Sm³⁺ ions were co-doped to produce a SrWO₄:[Sm³⁺]/[Dy³⁺] phosphor. When the Sm³⁺ ion concentration was increased and the Dy³⁺ concentration was maintained, the red light intensity increased while the blue-yellow light intensity decreased. The composites were combined with polydimethylsiloxane (PDMS), and a flexible composite material was fabricated. The composite exhibited various luminescence properties under UV and visible light, which suggested its potential for use as an LED color filter.

Luminescent Color-Adjustable Europium and Terbium Co-Doped Strontium Molybdate Phosphors Synthesized at Room Temperature Applied to Flexible Composite for LED Filter

In this study, terbium and europium rare-earth ions were single-doped and co-doped to synthesized SoMoO4 phosphor at room temperature. The samples prepared synthesized crystalline SrMoO4 powder by the co-precipitation. Samples had a tetragonal structure in XRD analysis and d(112) spacing was changed by rare-earth doping. As the amount of rare earth added increased, a secondary phase appeared, and the structure changed. The synthesized SrMoO4:Tb3+ phosphors showed a green light emission at 544 nm under 287 nm, SrMoO4:Eu3+ phosphors showed a red light emission at 613 nm under 290 nm, and SrMoO4:[Eu3+]/[Tb3+] phosphor showed a yellow-white light emission at 544 and 613 nm when excited at 287 nm. The synthesized phosphor exhibited a change in green and red luminescence intensity based on the amount of Eu3+ doped and showed strong red luminescence as the Eu3+ doping increased. To use the SrMoO4:[Eu3+]/[Tb3+] phosphor with these characteristics in an LED color filter, a flexible composite prepared by mixing with PDMS showed green, red, and yellow-white emission under a UV-lamp.

Photocatalytic degradation of methylene blue and dye mixture using indium-doped CaWO4 synthesized by sonochemical and microwave-assisted hydrothermal methods

Synthesis methods and characterization of indium-doped calcium tungstate particles.