جستجوی مقالات مرتبط با کلیدواژه "سنتز" در نشریات گروه "فیزیک"

In this article, a transparent gallium doped zinc oxide nanocomposite with a novel photoluminescence properties was prepared at room temperature. GZO nanocrystals were synthesized by the simple sol-gel method. The optical, structural and morphological properties of the samples were investigated by various analysis including photoluminescence spectrum, absorption spectrum, XRD, EDAX, FTIR, TEM and FESEM images. The XRD study showed that the samples had a wurtzite structure consistent with all crystalline plates of ZnO without any additional peaks or oxidation phases. Two nanocomposites containing dried nanopowders and the other containing calcined nanopowders were also prepared. Calcined nanocomposite exhibited good optical properties, including 70% optical transparency in the visible wavelength region with a high green emission peak at the room temperature. Also, the presence of gallium and zinc and related bonds in the structure was confirmed by EDAX and FTIR characterization. Studies have shown that the GZO composite has a novel luminance property in the blue-to-green visible region, which can be a good candidate for photo detection and photonic applications with a very low cost.

Nanoparticles of Yb-doped SrF2 were synthesized by co-precipitation method. The formation of nanostructures was confirmed by X-ray diffraction (XRD) pattern. The particle size of about 46 nm was calculated from XRD data. The shape and size of SrF2:Yb nanoparticles were also observed by scanning electron microscope (SEM). The computerized glow curve deconvolution (CGCD) method was employed to determine the number of component glow peaks and kinetic parameters of the synthesized nanoparticles. Its thermoluminescence (TL) glow curve contains three overlapping glow peaks at around 394, 435 and 488 K. TL response of this nanophosphor was studied for different Yb concentrations and the maximum sensitivity was found at 0.5 mol% of Yb impurity.

Cadmium tungstate nano powder (CdWO4) was synthesized with co-precipitation method. Two different types of material (based on acetate and nitrate) were used as precursors. The synthesized powder was characterized by X-ray powder diffraction (XRD)¡ scanning electron microscopy (SEM)¡ Fourier transfer Infrared absorption (FTIR) spectrum¡ and photoluminescent (PL) spectrum. According to the XRD pattern¡ two samples¡ nitrate based and acetate based were synthesizedwith average size of 31.0 and 30.0 nm¡ respectively. Besides¡ the response of two samples to the alpha particles was measured by using 3330 Bq241Am source. The respond of two samples to the alpha particles was acceptable and the central channels for them were occurred at the same channel. However¡ the count rate of the acetate based sample was 17.7% higher than the nitrate based sample. Since the sensitivity of two samples regarding to response to the alpha particles was acceptable¡ these two samples can be used as counter of the alpha particles.

Thallium doped calcium fluoride (CaF2:Tl) nanoparticles were produced for the first time by using the hydrothermal method. X-ray diffraction (XRD) and scanning electron microscope (SEM) were utilized to analyze the synthesized material. The particle size of about 45 nm was evaluated using XRD data which was supported by the SEM images. Thermoluminescence glow curve of this nanophosphor exhibits three overlapping glow peaks at 433, 466 and 505◦ K. The optimum concentration of activator was found at 1 mol% for TL responses relative to gamma rays of 60Co.The prepared nanoparticles exhibit a linear dose response up to 1000 Gy absorbed dose relative to gamma rays of 60Co source. Other dosimetric features of this novel phosphor are also presented and discussed.