Study on Dy2O3-Doped Medium Temperature Sintering (Ba,Sr)TiO3 Series Capacitor Ceramics

The influence of Dy₂O₃ doping on the properties of medium temperature sintering (Ba, Sr)TiO₃ series capacitor ceramics was studied by single factor various amount method, and the law of the influence on the medium temperature sintering (Ba, Sr)TiO₃ series capacitor ceramics was obtained. The dielectric materials used for multilayer ceramic capacitor was obtained, of which the dielectric constant was 1375, the dielectric loss was 0.0060, the density was 5.92 g·cm⁻³, the sintering temperature was less than 1150 °C, the capacitance temperature changing rate (ΔC/C) was less than ± 15%, the voltage withstand strength was more than 9.3 kV·mm⁻¹, and the crystal grain size was about 1 μm. The surface morphology of the sample doped with various amount Dy₂O₃ was analyzed by scanning electron microscope (SEM). The results showed that doping Dy₂O₃ could form defect solid solution, stop grain growth, fine crystal grain, widen curie peak, obtaining high dielectric constant and low dielectric loss, capacitance temperature property was suited for X7R character, in the (Ba,Sr)TiO₃ series ceramics. At the same time, the voltage withstand strength was enhanced greatly.     

Synthesis and photoluminescence properties of Er3+ and Dy3+ doped Na2NbAlO5 phosphors

A series of Ln³⁺ (Ln³⁺ = Er³⁺/Dy³⁺) ions doped Na₂NbAlO₅ (NNAO) phosphors were synthesized by solid-state method. The Er³⁺ and Dy³⁺ ions doped phosphors were characterized by XRD, photoluminescence (PL) and decay profiles. The Ln³⁺-doped samples are consistent with the pure NNAO phase which is analyzed by the X-ray diffraction result. The PL graphs show that the intensity of luminescence increases with the increasing doping concentrations up to their critical certain values and then decreases at higher concentrations due to the concentration quenching effect of Er³⁺/Dy³⁺ ions. The energy level diagrams containing the positions of 4f and 5d energy levels of Er³⁺ and Dy³⁺ ions have been established and studied. In addition, under the ultraviolet light, the prepared NNAO:xLn³⁺ (Ln³⁺ = Er³⁺/Dy³⁺) phosphors show the characteristic green (Er³⁺), cyan (Dy³⁺) emission, respectively. Under the excitation of 365 nm, the quantum efficiencies of NNAO:0.01Er³⁺ and NNAO:0.03Dy³⁺ phosphors are measured to be 61.7% and 72.2%, respectively. The obtained results indicate that the new NNAO:xLn³⁺ (Ln³⁺ = Er³⁺/Dy³⁺) phosphors are promising applications in white-light emitting diodes field.     

Spectroscopic investigations on Dy3+ ions doped zinc lead alumino borate glasses for photonic device applications

This paper presents the structural, optical absorption, photoluminescence (PL) and decay spectral properties of Dy~(3+)ions doped zinc lead alumino borate (ZPAB) glasses to elucidate their possible usage in photonic devices such as w-LEDs and lasers. A broad hump shown by the XRD spectrum recorded for an un-doped ZPAB glass confirms its non-crystalline nature. The Judd-Ofelt (J-O) intensity parameter evaluated from the measured oscillator strengths of the absorption spectral features were used to estimate various radiative parameters and also to understand the nature of bonding between Dy~(3+)ions and oxygen ligands. Under 350 nm excitation, the as-prepared glasses are exhibiting two emission bands~4F_(9/2)→~6H_(15/2)(blue),and~4F_(9/2)→~6H_(13/2)(yellow) at 483 and 575 nm,respectively. From the PL spectra,the Y/B ratio values, CIE chromaticity color coordinates and color correlated temperature (CCT) were evaluated. The experimental lifetimes measured from the decay profiles are decreasing with increase in Dy~(3+)ions concentration in these glasses which may be attributed to the cross-relaxation and nonradiative multiphonon relaxation process. Decay profiles observed for higher concentration were well fitted to Inokuti-Hirayama (I-H) model to understand the energy transfer process and subsequent decrease in experimental lifetimes. The higher values of radiative parameters, emission cross-sections,quantum efficiency, optical gain and gain band width suggest the suitability of 0.5 mol%of Dy~(3+) ions in these ZPAB glasses for the photonic device application.     

Physical,structural and optical studies on magnesium borate glasses doped with dysprosium ion

Intense visible emissions from dysprosium(Dy3+) ions doped glasses became prospective for diverse technological applications. In this paper, physical, optical and structural properties of magnesium borate glasses doped with varied concentrations of Dy_2 O_3 were examined. Such glasses were synthesised by melt quenching method and characterized at room temperature using several analytical techniques.Luminescence and absorption spectra(in the visible region) of as-quenched samples were used to evaluate the physical and optical properties. XRD pattern confims the amorphous state of as-quenched samples. The Fourier transform infrared(FTIR) spectra of glasses reveal various bonding vibrations assigned to different functional groups. UV-vis-NIR spectra disclose eight absorption bands accompanied by a band for hypersensitive transition positioned at 1260 nm(~6 H_(15/2)→~6 F_(11/2)). The values of direct and indirect optical energy band gap of the studied glasses are decreased with the increase of Dy~(3+) ion contents. The photoluminescence spectra of all glasses under the excitation of 380 nm display two prominent emission bands centred at 497 nm(~4 F_(9/2)→~6 H_(15/2), blue) and 587 nm(~4 F_(9/2) →~6 H_(13/2), green).The achieved intense luminescence from the proposed glass composition may be beneficial for solidstate laser applications.     

White light-emitting Ba0.05Sr0.95WO4:Tm3+ Dy3+ phosphors

Tm~(3+) and Dy~(3+) co-doped Ba_(0.05)Sr_(0.95)WO_4 phosphors were synthesized by a low temperature combustion method. The structures of the samples were SrWO_4 phase and were identified by X-ray diffraction. The surface topographies of Ba_(0.05)Sr_(0.91)WO_4:0.01 Tm~(3+) 0.03 Dy~(3+) were tested by scanning electron microscopy. The particles are ellipsoid, and their average diameter is approximately 0.5 μm. The emission spectra of Ba_(0.05)Sr_(0.95)WO_4:Tm~(3+) show a peak at 454 nm which belongs to the ~3 H_6→~1 D_2 transition of Tm~(3+), and the optimum doping concentration of Tm~(3+) ions was 0.01. The emission spectra of Ba_(0.05)Sr_(0.95)WO_4:Dy~(3+) consist of the ~4 F_(9/2)→~6 H_(13/2) dominant transition located at 573 nm, the weaker ~4 F_(9/_2→~6 H_(15/2) transition located at 478 and 485 nm. and the weakest ~4 F_(9/2)→~6 H_(11/2) transition located at660 nm, and the optimum doping concentration of Dy~(3+) ions was 0.05. A white light is achieved from Tm~(3+) and Dy~(3+) co-doped Ba_(0.05)Sr_(0.95)MoO_4 crystals excited at 352-366 nm. With the doping concentration of Tm~(3+) fixed at 0.01, the luminescence of Ba_(0.05)Sr_(0.95)MoO_4:Tm~(3+)Dy~(3+) is closest to standard white-light emissions when the concentration of Dy~(3+) is 0.03; the chromaticity coordinates are(0.321,0.347), and the color temperature is 6000 K.     

Solvent induced shape change in CePO4:Dy3+ nanophosphors and effect of metal ions:A photoluminescence study

The influence of different solvents and metal ions (Li+, Ba2+, Bi3+) on the crystallization behaviour, morphology and enhancement in photoluminescence intensity of Dy3+ doped CePO4 were investigated. Highly crystalline luminescent nanophosphors of CePO4:Dy3+ re-dispersible in polar solvents were successfully prepared via a simple polyol route at 140 ℃. As-prepared Dy3+ doped CePO4 nanophos-phors prepared in EG and DMF appeared to have crystalline monoclinic phase but exhibited hexagonal phase when prepared in water and water mixed solvents. The hexagonal phase transformed to monoclinic phase after heating at 900 ℃. TEM study revealed different shapes of the synthesized nanophosphors with change of solvents. The luminescence intensity of 4F9/2→6H15/2 at 478 nm (blue) was found to be more prominent than 4F9/2→6H13/2 at 572 nm (yellow). The introduction of metal ions (Li+, Ba2+ and Bi3+) in CePO4:Dy3+ led to considerable lumi-nescent enhancement. The nanophosphors were subsequently incorporated in polymer films of PVA which showed the characteristic emissions of Dy3+. It also served as an effective method to improve the performance of polymer materials and brought about novel properties in them.     

Evaluation of Dielectric Properties, Vibration Modes, and Crystal Structures in Ba[Zn(1?x)/3Ni x/3Nb2/3]O3 Ceramics

Microwave dielectric ceramics of Ba[Zn_(1?x)/3Ni _x/3Nb_2/3]O₃ (BZNN, x = 0.0, 0.5, 0.6, 0.7, 0.8) were sintered at 1773 K (1500 °C) for 3 hours by the conventional solid-state reaction method. To clarify the relationship between dielectric properties and crystal structures, vibration spectra (Raman spectroscopy and Fourier transform far-infrared reflection spectroscopy (FTIR)) and X-ray diffraction (XRD) were employed to study Ba[Zn_(1-x)/3Ni_x/3Nb_2/3]O₃ solid solutions. Crystal structures were determined as cubic perovskite structures, and no phase transition appears in substitution of Ni²⁺ to Zn²⁺ ions. Raman spectroscopy was used to discuss the correlation of dielectric properties with Raman shifts and full-width at half-maximum (FWHM) values, which indicate that dielectric properties are closely related to both FWHM values and A_1g(Nb) mode shifts. FTIR spectra and imaginary parts of dielectric constants were calculated to obtain the correlation between polar phonon modes and dielectric properties with Ni²⁺ concentration.     

Synthesis,Characterization and Photocatalytic Studies of La,Dy-doped ZnO nanoparticles

Rare earth La Dy co-doped ZnO nanoparticles (Zn_0.98La_0.01Dy_0.01O, Zn_0.96La_0.02Dy_0.02O, Zn_0.94La_0.03Dy_0.03O, and Zn_0.92La_0.04Dy_0.04O) were synthesized by co-precipitation method at temperature of 500 °C for 2 h in air. The synthesized samples were characterized by powder X-ray diffraction (XRD), FE-SEM/EDS and UV–Visible spectrophotometer. The prepared nanoparticles exhibit a hexagonal wurtzite structure as observed from XRD measurements. It was observed that the La Dy co- doped ZnO nanoparticles (Zn_0.98La_0.01Dy_0.01O, Zn_0.96La_0.02Dy_0.02O, Zn_0.94La_0.03Dy_0.03O, and Zn_0.92La_0.04Dy_0.04O) exhibit higher optical absorbance spectrum at 400 nm to 800 nm wavelength due to its smaller crystal size (12.2 nm) as compared to the un- doped ZnO nanoparticles (253.1 nm). The photocatalytic activity of rare earth La Dy co- doped ZnO nanoparticles were studied by performing the decomposition of methylene blue dye solution under UV light irradiation within 0–4 h. The methylene blue dye solution was considerably photodegraded by Zn_0.92La_0.04Dy_0.04O photocatalyst under UV light irradiation within 2–4 h to the efficiency of 96 %. The pseudo first order rate constant of the degradation was found to be 0.0264 S^?1. The degradation mechanisms are discussed in this work.     

Luminescence properties of dysprosium doped YVO4 phosphor

Trivalent dysprosium(Dy~(3+)) activated nanocrystalline yttrium vanadate(YVO_4) phosphor was synthesized via co-precipitation method. The prepared samples were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), optical absorption and photo luminescence(PL) techniques. The XRD patterns reveal the tetragonal crystalline phase. SEM images reveal that Dy doped YVO_4 nanocrystals are agglomerated. EDAX confirms the formation of YVO_4:Dy. FTIR spectrum shows two strong absorption bands at 459 and 761 cm~(-1). Optical absorption spectrum showed the surface defects in the as-prepared samples. The PL emission spectrum shows two characteristic emission bands at 485 and 575 nm. The strong yellow emission peak at 575 nm is assigned to ~4 F_(9/2)→~6 H_(13/2) hyper sensitive transition of Dy~(3+) ions, Study of CIE chromaticity diagram indicates the suitability of the phosphor for the development of yellow-green LEDs.     

Effect of Sr~(2+) and Dy~(3+) co-doping on coloration and temperature stabilization of a γ-Ce_2S_3 red pigment

In this paper,a Sr~(2+)and Dy~(3+)co-doped γ-Ce_2S_3 red pigment was synthesized via a combination of coprecipitation and sulfurization processes.Mixed oxide was prepared by presintering the coprecipitates,(Ce,Sr,Dy)CO_3,followed by high-temperature sulfurization under a CS_2 atmosphere.The effects of the sulfurization temperature,time,and doped proportion on the phase composition,color performance and temperature stability of γ-Ce_2S_3 were systematically studied.The results show that a stable γ-Ce_2S_3 red pigment can be obtained through Sr~(2+)and Dy~(3+)co-doping at 730℃ for 200 min.The diffraction peaks of all the samples shift to higher 2θ values with increasing doping proportion,indicating that part of the Dy~(3+)species enter the lattice and form a solid solution.The band gap of the samples remains practically constant at 2.01-2.04 eV,which causes their red color.The best red-color quality(L~*=37.13,a~*=34.77,b~*=29.44) is achieved when the pigment has a Dy~(3+)/Ce~(3+)molar ratio of 0.15,and the material maintains its excellent red color(L~*=31.49 a~*=30.94 b~*=25.33) after being heated at 410℃ for 30 min.     

Optical properties and Judd–Ofelt analysis of Nd2O3 nanocrystals embedded in polymethyl methacrylate

PMMA matrices were doped with nano-crystalline neodymium oxides synthesized by thermal decomposition process. X-ray diffraction and high-resolution transmission electron microscopy measurements were carried out to investigate the structure, phase, and the morphology of the Nd_2O_3 nanocrystals and those embedded in the PMMA matrix. The average grain sizes were estimated 35 ± 6 nm and 46 ± 4 nm for non-annealed and annealed Nd_2O_3 particles, respectively. The grain size distributions(GSD) were calculated from the diffraction peaks of the annealed and non-annealed Nd_2O_3 powders and doped PMMA samples. The mass density, refractive index. UV-Visible absorption spectra were measured and the data were analyzed using the Judd-Ofelt approach to determine the oscillator strengths, the spontaneous emission probabilities and the branching ratios as a function of the nano-crystalline Nd_2O_3 content in the range of 0.1 wt.%-20 wt.% of MMA. Luminescence spectra upon 808 nm diode laser excitation were carried out in the wavelength range of 850-1550 nm at room temperature. The photoluminescence study has shown that the reasonably sharp emission peaks were observed upon heat treatment at 800 ℃ for 24 h for all concentrations of Nd_2O_3 nanopowders in PMMA. The infrared laser transition of Nd~(3+) ions at about 1.06 μm due to the ~4F_(3/2)→~4I_(11/2) transition was analyzed and discussed in Nd_2O_3 system for their possible applications in the photonic technology.     

Synthesis of Dy2O3 nanoparticles via hydroxide precipitation： effect of calcination temperature

This work described the preparation of dysprosium oxide, Dy2O3, nanoparticles using the homogeneous precipitation method. Dy3+ ions were precipitated using NaOH solution. The obtained product was filtered, dried, and then calcined for 1 h at the temperature range of 300–700 °C in static air. The calcination temperature of the Dy-precursor was chosen based on its decomposition as indicated by the TGA analysis. The crystalline structure and surface morphology of the calcined solids were studied by X-ray diffraction(XRD), field emission scanning electron microscopy(FE-SEM), transmission electron microscopy(TEM) and X-ray photoelectron spectroscopy(XPS). The obtained results revealed that Dy2O3 with crystallites size of 11–21 nm was formed at 500 °C. Such value increased to 25–37 nm for the sample calcined at 700 °C.     

Effect of Yttrium Doping in Barium Zirconium Titanate Ceramics: A Structural, Impedance, and Modulus Spectroscopy Study

In the current article, we studied the effect of yttrium [Y³⁺] ions’ substitution on the structure and electric behavior of barium zirconate titanate (BZT) ceramics with a general formula [Ba_1?x Y_2x/3](Zr_0.25Ti_0.75)O₃ (BYZT) with [x = 0, 0.025, and 0.05] which were prepared by the solid-state reaction method. X-ray diffraction patterns indicate that these ceramics have a single phase with a perovskite-type cubic structure. Rietveld refinement data confirmed [BaO₁₂], [ZrO₆], [TiO₆], and [YO₆] clusters in the cubic lattice. The Y³⁺ ions’ effects on the electric conductivity behavior of BZT ceramics as a function of temperature and frequency are described, which are based on impedance spectroscopy analyses. The complex impedance plots display a double semicircle which highlights the influences of grain and grain boundary on the ceramics. Impedance analyses showed that the resistance decreased with the increasing temperature and resulted in a negative temperature coefficient of the resistance property in all compositions. Modulus plots represent a non-Debye-type dielectric relaxation which is related to the grain and grain boundary as well as temperature-dependent electric relaxation phenomenon and an enhancement in the mobility barrier by Y³⁺ ions. Moreover, the electric conductivity increases with the replacement of Ba²⁺ by Y³⁺ ions may be due to the rise in oxygen vacancies.     

Chemical State, Site, Solid Solubility, and Magnetism of Fe in the Ferropericlase (Mg1–x Fe x )O Produced by Ball Milling of MgO and Fe

Ferropericlase (Mg_1–x Fe _x )O solid solution was prepared by ball milling of the mixture of MgO with a rock-salt structure and metal Fe powders in atmosphere and at room temperature. Differing from (Mg_1–x Fe _x )O prepared at high temperature by using MgO and FeO as starting materials, the solution of Fe in MgO is not continuous but limited in the ball milling process, and the solubility limit is less than 30 at. pct. About 92 pct of the Fe ions occupy the site of tetrahedral oxygen coordination in trivalent Fe (Fe³⁺) with high spin, whereas about 8 pct of the Fe ions occupy the site of octahedral oxygen coordination in bivalent Fe (Fe²⁺) with high spin. The Fe³⁺ and Fe²⁺ ions do not show a ferromagnetic but show a paramagnetic state. The as-milled (Mg_1–x Fe _x )O is metastable and decomposes to ferropericlase (Mg_1–y Fe _y )O (where y < x) and MgFe₂O₄ with spinel structure as annealed above 773 K (500  °C), and the content of Fe in the (Mg_1–y Fe _y )O increases with increasing annealing temperature. A bulk (Mg_1–x Fe _x )O was fabricated by annealing the as-milled (Mg_1–x Fe _x )O powders at 973 K (700  °C). It shows n-type conductivity, which is attributed to an electronic small polaron with an activation energy of 0.135 eV.     

Effect of V2O5–TeO2 Glass Addition on Dielectric Properties of CaCu3Ti4O12 Ceramics Prepared by Solid State Method

CaCu₃Ti₄O₁₂ (CCTO) is well known to have colossal dielectric constant in the range of 10⁵. However, CCTO has considerably high dielectric loss values (tanδ > 0.1) at room temperature and 1 kHz. In this work, addition of glass to CCTO was suggested in order to improve its dielectric properties. The effect of V₂O₅–TeO₂ (VT) glass addition on microstructure and dielectric properties of CCTO ceramics were investigated. Dielectric measurements were carried out for (1 ? x) CCTO-(x) V₂O₅–TeO₂ (x = 0, 0.03, 0.05, 0.10) samples in the frequency range of 10²–10⁶ Hz using impedance spectrometer. Electron micrographs showed that low melting VT glass addition facilitated the grain growth of CCTO. As VT glass amount increased, dielectric constant decreased. The drop, though within reasonable values (~10⁵), may related to the presence of grain boundary glassy phase which itself has low dielectric constant. However, the dielectric loss of the composite has decreased after VT glass addition. The low melting V₂O₅–TeO₂ glass aided in liquid phase sintering and improved the grain boundary resistance which resulted in decreased leakage currents.     

Comparison of thermoluminescence spectra of MgB407 doped with dysprosium and manganese

A series of magnesium borate phosphors MgB4O7：Dy, MgB4O7：Mn and MgB4O7：Dy,Mn were prepared and their ther-moluminescence （TL） emission spectra were measured. TL emission bands in 480, 575 and 660 nm at 200 and 360 oC were observed in the MgB4O7：Dy due to the transitions of the trivalent rare earth ions Dy3＋. The glow peaks of broad wavelength band around~580 nm at 180 and~290 oC were observed in MgB4O7：Mn due to the emission of Mn2＋ions. The main glow peak of MgB4O7 co-doped with Dy and Mn appeared in 580 nm at~360 oC. When MgB4O7 was co-doped with Dy （0.5 mol.%） and different concentrations of Mn （0.01 mol.%-1.0 mol.%）, the peak in 580 nm at 360 °C was intensified and broadened as the concentration of Mn increased, while the peaks in 480, 680 and 750 nm below 300 °C remained the characteristic emission of Dy3＋and were reduced in intensity. The emission spectra of the MgB4O7：Dy,Mn phosphor showed that the competitive de-excitation processes between Dy3＋and Mn2＋existed and the energy transfer occurred from Dy3＋to Mn2＋. These results meant that rare earth and Mn ions in MgB4O7：Dy,Mn might cause the formation of defects complex that dominated the traps and recombination.     

Synthesis and characterization of YAG: Ce3+ fluorescence powders by co-precipitation method

YAG:Ce³⁺(Yttrium aluminum garnet) fluorescence powders were successfully prepared by co-precipitation method using aluminum nitrate, yttrium nitrate, cerous nitrate as the starting materials and ammonium carbonate as precipitant. The products were characterized by X-ray powder diffraction, luminescence spectrometer, transmission electron microscope (TEM). The XRD results showed that the obtained YAG:Ce³⁺ fluorescence powders had the crystalline structures of YAG at calcinations temperature of 900 °C and the TEM results showed that the grain diameters were about 100 nm. The YAG:Ce³⁺ fluorescence powders, synthesized by co-precipitation method, had the best luminescence property when the Ce doping amount was x=0.06 in the molecular formula of Y_3-xCe_xAl₅O₁₂, the calcinations time was 2 h and the calcinations temperature was 1000 °C.     

Effect of Dy-substitution on structural and magnetic properties of MnZn ferrite nanoparticles

This paper describes the structural and magnetic properties of Dy-substituted Mn-Zn ferrite nanoparticles. Mn-Zn-Dy ferrite nanoparticles of the composition Mn_(0.5)Zn_(0.5)Dy_xFe_(2-x)O_4(x=0.05, 0.1,0.15 and 0.2) were synthesized by a facile chemical co-precipitation method. The samples were characterized through X-ray diffraction(XRD), transmission electron microscopy(TEM), Fourier transform infrared spectroscopy(FTIR), vibrating sample magnetometer(VSM) and Curie temperature. The XRD patterns confirm the synthesis of single crystalline phase of Mn-Zn-Dy ferrite nanoparticles. Lattice parameter increases with increase in Dy-substitution which confirms the replacement of Fe~(3+) ions by Dy~(3+) ions.Crystallite size is of the order of 6-8 nm for all these samples. The particle sizes observed from TEM analysis are in good agreement with the XRD values. The magnetic measurements show superparamagnetic nature of the samples. The saturation magnetization decreases with increase in Dyconcentration and can be correlated to modifications in the A-B exchange interactions as a result of the structural modifications due to Dy-substitution. The Curie temperature for Mn_(0.5)Zn_(0.5)Fe_2 O_4 nanoparticles is 124 ℃ and decreases up to 84 ℃ with the increase in the Dy-concentration. The decrease in Curie temperature can be attributed to the weakening of the superexchange interaction between A-site and B-site as a result of Dy-substitution. The low value of Curie temperature and higher value of thermomagnetic coefficient k_T shown by these samples makes them suitable for the preparation of temperature sensitive ferrofluid for heat transfer applications.     

Optically stimulated luminescence of Dy~(3+)-doped NaCaPO_4 glass-ceramics

Dy~(3+)-doped glass-ceramics containing NaCaPO_4 crystals were successfully fabricated by heat treatment at base glass,and the luminescence properties were investigated for potential applications in radiation measurements.The photo luminescence(PL) excitation and emission spectra exhibit transitions related to Dy~(3+) ions corresponding to the strongest excitation and emission wavelengths at 351 and 575 nm,respectively.The CW-OSL properties as a function of dopant concentration,pre-heating temperature,pre-heating time and signal fading were investigated.The most appropriate Dy~(3+)ion concentration was found to be 0.25 mol%.The TL glow curves have a broad peak feature peaking at 195±5 ℃.The fading of the OSL signal would keep stable in five days with the intensity value of about 76.11%.The samples also exhibit good signal reusability and a broad linear dose response range(0.02-1000 Gy).     

Luminescent characterization of rare earth Dy3+ ion doped TiO2 prepared by simple chemical co-precipitation method

Pure and rare-earth ion (Dy³⁺) doped TiO₂ nanomaterials were prepared through a chemical co-precipitation method. The chemical composition, microstructure and optical properties were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-visible spectroscopy and photoluminescence (PL). XPS analysis reveals that Dy³⁺ ions are preferentially occupied in the TiO₂ crystallite lattices. Both the XRD and TEM analyses confirm that both the pure and Dy doped TiO₂ are in pure anatase phase and in nano size range, respectively. Also it is found that the maximum solubility limit for Dy³⁺ ions is found to be 0.4% in TiO₂ matrix, above which it occupies interstitials and/or crystallite surface of TiO₂ nanocrystals. From the UV-Vis spectroscopy studies it is found that Dy doping induces blue shift in TiO₂. From the PL analysis it is found that doping Dy³⁺ improves the luminescence behavior in comparison with the pure TiO₂ nanoparticles. Overall, doping very low concentrations of Dy³⁺ greatly alters the structural morphology and directly increases the luminescence behavior of TiO₂ suitable for advanced optoelectronic applications.