Thermoluminescence study of Barium based composite phosphor using gamma rays.

The present paper reports the synthesis and characterization of Ag+ doped (Cd0.95Zn.05)S phosphors. The effect of variable concentration of silver on thermoluminescence (TL) studies was investigated. The samples were prepared by solid state synthesis technique which is suitable for large scale production for phosphors. The starting materials used for sample preparation were CdS, ZnS, (Ag(NO3)3 and sodium chloride was used as a flux during synthesis. The prepared sample was characterized by X-ray diffraction technique (XRD). Sample shows hexagonal structure and the particle size calculated by Scherer’s formula. The prepared phosphors were also examined by thermoluminescence technique. For recording TL glow curve every time 2mg phosphor was irradiated by 254nm UV source and fixed the heating rate at 8 0 C s -1 . Sample shows wellresolved peak at 1020C for different concentration of Ag+. In addition, the effect of Ag+ concentration at fixed UV exposure time was studied. The effect of UV exposure time and dose versus intensity plot were studied. Sample shows linear response with dose and broaden peak with lower temperature shows the less stability and more fading in TL glow curve. Trapping parameters were calculated for every recorded glow curve. The heating rate effect on TL glow curve was also studied. The sample shows the shifting of TL glow curve towards to lower temperature side with increasing of heating rate. The kinetic parameters like trap depth, frequency factor were calculated by using the Peak shape method, which are discussed in details. The TL Glow curves were fitted in CGCD (computerized glow curve convolution deconvolution) technique & trapping parameters calculated.

Investigation of luminescence properties of Dy3+ doped YAlO3 phosphors synthesized through solid state method

In this article, pure and 2 M% dysprosium (Dy)-doped α-MoO3 nanobelts have been successfully synthesised by the autoclave assisted-hydrothermal method. The x-ray diffraction (XRD) patterns revealed that the nanobelts were crystalline in nature with an orthorhombic structure. The sharp and narrow XRD peaks divulged the high quality with good crystallinity of the nanobelts. The intensity of the peak (040) increased and shifted towards lower 2θ values which reflected the successful incorporation of Dy in MoO3 matrix. The scanning electron microscopy (SEM) images revealed the formation of randomly distributed nanobelts with average width of 90–150 nm and length of 950–1300 nm. Vibration behaviour of chemical bonds was characterised by Fourier-transform infrared spectroscopy (FTIR) and the detected peaks confirm the formation of orthorhombic structure of MoO3. The energy dispersive x-ray spectroscopy (EDX) spectra confirmed the Dy incorporation in the MoO3 matrix. Debye–Scherrer method, Wilson method, Williamson Hall (W − H) and Halder-Wagner (H − W) analyses have been employed to investigate the different parameters (such as crystallite size and lattice strain) and to analyse their contribution on the XRD peak broadening of the nanobelts. The crystallinity improved as the average crystallite size increased, and FWHM, lattice strain and dislocation density decreased after Dy doping. The obtained values of crystallite size estimated using Debye–Scherrer equation, and W − H and H − W plots, are nearly similar, highly inter-correlated and in the range of 26.06–31.44 nm. The Halder-Wagner (H-W) plots give the more precise results of different microstructural parameters by analysing XRD peak broadening of both samples compared to Debye–Scherrer and Williamson Hall methods.

The present paper reports the synthesis of cadmium and mercury free lamp (Y, Gd)BO3: Eu3+ phosphor which is in nano range useful for display device application. The phosphor doped with Eu3+ was synthesized by the solid state reaction method which is suitable for large scale production and eco-friendly. The prepared phosphor was characterized by the X-ray diffraction technique (XRD), field emission gun scanning electron microscopy (FEGSEM) and transmission electron microscopy (TEM). The optical behaviour of the prepared phosphor was determined by photoluminescence (PL) spectra recorded in room temperature. The PL excitation spectra were found at 470nm and the emission spectra cover all visible regions (419–625nm) which indicate that the prepared phosphor can act as a single host for white light emitting diode (WLED) application and verified by Internationale de I’Eclairage (CIE) techniques. The thermoluminescence (TL) glow curve was recorded for Eu3+ doped (Y, Gd)BO3 phosphor. The TL glow curve was recorded for UV, beta and gamma irradiations and also the kinetic parameters were calculated. In addition to this trap parameters of prepared phosphor were studied using computerized glow curve deconvolution (CGCD).

This study reports the thermoluminescence (TL) aspects of Ca10 K(PO4 )7 :Dy phosphor synthesized using a wet chemical method for the first time. The X-ray diffraction (XRD) results confirm the formation of the desired crystalline phase. Surface morphological studies reveal the formation of polyhedrons and agglomerations having an average diameter of 200 nm, while energy dispersive X-ray spectroscopy (EDS) data show the presence and composition of the elements in appropriate amounts. The effect of Dy doping concentration has been studied on the TL properties with exposure to gamma radiations from the Co-60 source. The best TL response has been observed for 5mol% Dy doping concentration. The glow curve is simple and consists of a single peak at 130°C. The effect of the heating rate has been studied on the TL glow curve, and the heating rate of 5°C/s shows the best TL response. The various TL properties such as annealing conditions, dose-response, TL linearity, fading, and reusability of the prepared phosphor have been studied to check its suitability as a good TL dosimeter (TLD). TL characterization of the phosphor reports that the TL response is linear from 5- to 2000 Gy. The results show that this phosphor can be a good TLD for the dosimetry of gamma radiations from Co-60.

Monovalent cations such as Li (1 mol%) co-doped in GdAlO3:Eu3+ phosphors were synthesised by solution combustion technique using oxalyl dihydrazide (ODH: C2H6N4O2) as a fuel. X-ray diffractometer (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and photoluminescence (PL) techniques have been employed to characterise the synthesised nanoparticles. All the compounds crystallised are in the pure orthorhombic phase with no impurity peak. SEM showed the porous, agglomerated and irregular shaped crystallites. The crystallite size was calculated by the Debye Scherrer's method and was found to be in the range 40-45 nm. Photoluminescence (PL) measurements were carried out for GdAlO3:Eu3+ and GdAlO3:Eu3+, Li+ phosphors. The characteristic emission peaks of Eu3+ ions were recorded at 590 and 597, 615 and 627, 650 and 695 nm corresponding to 5D0 → 7FJ (J = 1, 2, 3, 4) transitions respectively. The PL intensity of GdAlO3:Eu3+ phosphor was improved evidently by co-doping with Li+ ions whose radius is less than that of Gd3+. The effect of co-dopant on enhanced luminescence was mainly regarded as the result of a suitable local distortion of crystal field surrounding the Eu3+ activator. These results will play an important role in seeking some more effective co-dopants. The CIE colour coordinates values of these phosphors are determined using CIE 1931 standard. These phosphors can act as a potential candidate in white LEDs and solid state lighting applications.

Luminescence behaviour was displayed by dysprosium (Dy3+) doped BaTiO3 phosphor which was synthesized via solid state reaction method. The method is suitable for large scale production and useful for production of micron size phosphor. The sample was characterized by X-ray diffraction technique and crystallite size was calculated using Scherer’s formula. Effects of optimized concentration of Dy3+ on its thermoluminescence glow curve analysis were carried out for γ irradiation. For fixed concentration of dysprosium ions the TL glow curve was recorded using 6.7 °C s−1 heating rate. Also for variable γ dose 1–2.5 kGy and optimized concentration of dysprosium ion i.e. 4 mol% were carried out. It is found that TL glow curve shows linear response with γ dose. Kinetic parameters were calculated using computerized glow curve deconvolution technique. Photoluminescence study of Dy3+ doped BaTiO3 phosphor was carried out and it is found that the PL emission spectra in visible region had blue, green and red emission wavelength. CIE coordinate shows color rendering index and correlated color temperature for white light emission of Dy3+ doped BaTiO3 phosphor. It may be used for visible light emission in display device applications and TL dosimetric applications.

In this paper, we reports synthesis, characterization and thermoluminescence (TL) glow curves of europium and dysprosium activated zirconium dioxide (ZrO2: Eu3+, Dy3+) phosphor with variable concentration of europium and fixed concentration of dysprosium. The sample was prepared by the Solid state method; thereafter, the TL glow curves were recorded for different concentration of europium with 20 min UV exposure at a heating rate of 6.7°C/s. The trapping parameters for synthesized phosphors of ZrO2: Eu3+, Dy3+ have been calculated by using a peak shape method. The sample was characterized for structural analysis by XRD (X-ray diffraction) and morphological analysis by FEGSEM (field emission gun scanning electron microscope) and FTIR (Fourier transform infrared spectroscopy). The effect of variable europium concentration and fixed dysprosium concentration on TL studies were interpreted and the formation of trap depth and reproducibility of prepared phosphor were analyzed by TL glow curves. The peak tempera...

This study observed the effect of the addition of iron (Fe) doping on the characteristics of Zinc Oxide (ZnO) nanoparticles.Zn(1-x)Fe(x) with various concentration of x = 0, 2, 4, 6, 8, and 10% was prepared by coprecipitation method using Sodium Hydroxide and Hydrogen Chloride. The effect of adding Fe doping on ZnO was characterized using X-ray Diffraction (XRD) to determine the crystal structure, size, and strain. The analysis result confirmed the absence of additional impurity peaks in the ZnO nanoparticles. Fe doping affects the Zn lattice structure. X-ray diffraction (XRD) study confirms the crystalline Hexagonal structure. Crystal size analysis using Debye Scherrer, UDM, and Halder-Wagner method obtained varying crystal sizes with variations in the concentration of Fe ranging from 19.89-44.72 nm. The crystal size and strain obtained from the Debye Scherrer method are smaller

Zinc oxide nanoparticle in lithium triborate microparticle system: Visibility for application in dosimetry

The nanoparticles of Co0.75Ni0.25Fe2−zDyzO4 (z = 0.0 and 0.05) were prepared by the sol-gel auto-combustion method. The cation distribution was calculated from the Rietveld refinement of the XRD pattern to confirm a mixed inverse spinel structure. The crystallite size was calculated by the Debye–Scherrer method, modified Scherrer method, Williamson Hall plot method, and size-strain plot method for prepared samples. The variation in crystallite size was observed due to the contribution of lattice strain on line peak broadening. From Fourier transform infrared (FT-IR) spectrum the absorption bands appeared at 574.79 cm−1 and 414.70 cm−1 reveals spinel ferrite structure for Co0.75Ni0.25Fe1.95Dy0.05O4. The particle size from a high-resolution scanning electron microscope (HR-SEM) the image was found to be 46.99 nm for Co0.75Ni0.25Fe1.95Dy0.05O4. Energy-dispersive X-ray spectrum (EDS) was confirmed the purity of the sample with good stoichiometry. The coercivity, retentivity, and saturation magnetization were estimated at 841.97 Oe, 30.95 emu g−1 and 61.80 emu g−1 respectively for Co0.75Ni0.25Fe1.95Dy0.05O4. The squareness ratio for Co0.75Ni0.25Fe1.95Dy0.05O4 nanoferrite was found to be 0.5 which is the ideal Stoner—Wohlfarth value. The experimental estimated net magnetic moment ( nB ) per formula was less than the theoretical value calculated from Neel’s two sublattice model for prepared samples.

MgO:Li+ phosphor: In depth analysis of its structural, optical and thermoluminescent behavior after gamma irradiation

Effect of dopant concentration on luminescence properties of a phosphor KCaPO4: Dy

Synthesis, characterization and luminescence behavior of ZrO2:Eu3+, Dy3+ with variable concentration of Eu and Dy doped Phosphor

Thermoluminescence glow curves in preheated feldspar samples: An interpretation based on random defect distributions