Influence of chemical substitution on the photoluminescence of Sr(1−)Pb WO4 solid solution

Phase Transformation, Photocatalytic and Photoluminescent Properties of BiPO4 Catalysts Prepared by Solid-State Reaction: Degradation of Rhodamine B

Polycrystalline bismuth phosphate BiPO4 was synthesized by solid-state reaction at different temperatures varying from 500 to 900 °C. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDS) and Raman spectroscopy. The low-temperature phase of BiPO4 has monoclinic structure with a space group P21/n, and was transformed into the monoclinic phase P21/m with a slight distortion of monoclinic lattice when it was heated above 500 °C. The effect of the transformation on the structure, morphology and photocatalytic properties was examined. The photocatalytic activity of each sample, in presence of Rhodamine B (RhB) in aqueous solution, was carried out and analyzed under UV light irradiation. Photoexperiments showed that the material prepared at 500 °C is the best catalyst with degradation efficiency of the order of 96% after 12 min of reaction time under UV light irradiation. This high photocatalytic efficiency could be due to their structural and morphological changes. The photocatalytic degradation mechanism of RhB in the presence of the best photocatalyst BiP-500 °C is proposed. The stability of the catalyst was also examined by carrying out four successive tests of the degradation in the presence of BiP-500 °C. Total organic carbon (TOC) was used to further estimate the rate of mineralization in the presence of BiP-500 °C (83% TOC removal). Photoluminescence experiments performed under UV-laser light irradiation revealed emissions in the green-orange range, with optimal intensities for the mix systems observed at 550 °C.

Probing emission and defects in BaWxMo1–xO4 solid solutions: achieving color tunable luminescence by W/Mo ratio and size manipulation

This work highlights the size, structure, and composition manipulation for designing color-tunable phosphors based on doped scheelite micro- and nanocrystals.

Effect of morphology and temperature treatment control on the photocatalytic and photoluminescence properties of SrWO4 crystals

This work reports the combined effect of the morphology and crystallization degree of the strontium tungstate (SrWO₄) scheelite structure on its photocatalytic and photoluminescence properties.

Unexpected formation of scheelite-structured Ca1-xCdxWO4 (0 ≤ x ≤ 1) continuous solid solutions with tunable photoluminescent and electronic properties

Design of a solid solution with tunable functionality is an attractive strategy toward realizing novel devices with multi-functionalities. In this work, a series of Ca_1-xCd_xWO₄ solid solutions in the entire range 0 ≤ x ≤ 1 with tetragonal scheelite structure have been successfully prepared for the first time. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and Fourier transform Raman (FT-Raman) spectroscopies indicated that all the nanocrystals have a tetragonal scheelite structure without wolframite phase. Structural refinement data revealed that the lattice volume decreased with the replacement of Ca²⁺ by Cd²⁺ ions. UV-Vis diffuse reflectance spectra indicated that optical band gap reduced with the replacement of Ca²⁺ by Cd²⁺ ions. Scanning electron microscopic (SEM) images showed that morphologies of the nanocrystals changed with the chemical compositions. The structure evolution of the solid solutions was further investigated by high-resolution transmission electron microscopy (HRTEM). Moreover, the influence of chemical compositions on the photoluminescent and electric performance has been performed and discussed. The reported synthetic approach and findings reported here are important to understand the structure and structure-property relation of scheelite-structured tungstate and molybdate compounds, which has potential applications in the design of other kinds of novel functional materials.