جستجوی مقالات مرتبط با کلیدواژه « X-ray » در نشریات گروه « شیمی »

In this study, structural studies, photoluminescence and thermoluminssence properties of CaZrO3 nanoparticles added with Ce3+ ion at different concentrations (x = 0.1-0.6 mol%) were investigated. Structural analysis of the samples was performed by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The XRD pattern indicated the formation of a perovskite structure at 700 °C. The thermoluminssence (TL) properties of CaZrO3:xCe3+ nanophosphors were investigated at room temperature under X-ray at different times. Maximum TL intensity was obtained for Ca0.998Ce0.002ZrO3 samples. The sample of Ca0.998Ce0.002ZrO3 was exposed to X-ray at different time intervals from one to 15 minutes. As the irradiation time increases, the number of charge carrier increases, which results in an increase in the intensity of TL. Linearity, reproducibility and fading were also investigated for this sample, which is suitable for TL dosimetry due to its significant stability, low fading and linearity of the TL response. Study of photoluminescence (PL) behavior at room temperature showed when the phosphors were excited by light with a wavelength of 253 nm, three emission peaks at 404, 425 and 488 nm were obtained, respectively. By increasing Ce concentration, the emission peaks in PL spectra slightly shift from violet region to blue region.

In this study, CaZrO3 nanophosphors with perovskite structure were synthesized by self-combustion method with citric acid as fuel at 350 °C and XRD patterns were performed at different temperatures to evaluate the optimum temperature of single-phase and crystalline CaZrO3 samples. The average size of crystals for the apparent peak (121) was estimated to be 44 nm using Scherer formula. The morphology of the samples using FE-SEM and EDXS indicated the nanometer size of the samples and the formation of desired phases in the sample. The photoluminescence (PL) emission spectrum of a sample under the excitation wavelength of 256 nm has a broad band around 435 nm (visible region) in the blue region of the electromagnetic spectrum. The results of thermoluminescence (TL) analysis also showed that the CaZrO3 sample made by this method shows TL properties even in the absence of impurities. Nanophosphors were irradiated with UV light at 254 nm at different times and its radiative peak was quite visible in the thermoluminescence curve at 204 °C. Also, CaZrO3 nanophosphors were irradiated with X-ray at different times and its thermoluminescence curve included a single peak at 209 °C. The linearity, reproducibility and fading of CaZrO3 were investigated under UV and X-ray irradiation.