Luminescence properties of La2O3:Eu3+ nanophosphor prepared by sol-​gel method

Undoped and Eu3+ doped La2O3 nanophosphor are synthesized by low temp. sol-​gel technique. The synthesized samples are characterized by X-​ray diffraction (XRD) and av. crystallite size is found to be ∼18 nm and ∼23 nm for undoped and Eu3+ doped La2O3 resp. Gamma ray irradiated undoped La2O3 shows high intense thermoluminescence (TL) glow peak at 640 K and weak TL glow peak at 443 K and the high intense peak intensity is sub linear increase with γ-​dose. Whereas Eu3+ doped La2O3 nanophosphor show a prominent TL glow peak at 640 K and its TL intensity linearly increases up to 1 kGy. The kinetic parameters are estd. using glow curve deconvoluted (GCD) technique. TL emission of γ-​ray irradiated Eu3+ doped La2O3 show peaks at 508, 586, 619 and 706 nm are attributed to Eu3+ transition peaks

Ion Beam Induced Cubic To Monoclinic Phase Transformation of Nanocrystalline Yttria

Sol gel derived nanocrystalline yttria pellets are irradiated with 120 MeV Ag9+ ions for fluence in the range 1 � 1012–3 � 1013 ions cm2 . Pristine and irradiated samples are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy. XRD pattern of pristine Y2O3 nanocrystal reveal cubic structure. A new XRD peak at 30.36� is observed in pellet irradiated with 1 � 1013 ions cm2 . The peak at 30.36� is corresponding to ð4 0 � 2Þ plane of monoclinic phase. The diffraction intensity of ð4 0 � 2Þ plane increases with Ag9+ ion fluence. Raman spectrum of pristine pellet show bands corresponding to cubic phase. And, ion irradiated sample show new peaks at 410, 514 and 641 cm1 corresponding monoclinic phase. HR-TEM and SAED pattern of ion irradiated sample confirmed the presence of monoclinic phase. Hence, it is confirmed that, 120 MeV Ag9+ ions induce phase transformation in nanocrystalline Y2O3

Luminescence studies of 100Â MeV Si8+ ion irradiated nanocrystalline Y2O3

Combustion synthesized Y2O3 revealed cubic structure and the average cry stallite size is found to be 32.73 nm. FTIR spectra revealed YeO, OH stretching and CeO bending bonds. Y2O3 pellets are irradiated with 100 MeV Si8þions in the fluence range 11010 to 11014ions cm2. PL of irradiated samples shows emission with peaks at 417, 432, 465 nm. Y 2O3 shows a prominent well resolved TL glow with peak at 403 K (Tm1) and a weak TL peak at 461 K (Tm2). TL intensity in the present work increases up to about 11011ions cm2 there after it decreases. The TL kinetic parameters are calculated by glow peak shape method. Activation energy and frequency factors are found to in the range of w1.6 eV andw 1018 s1 respectively

Effect of 100 MeV swift Si8+ ions on structural and thermoluminescence properties of Y2O3:Dy3+nanophosphor

Nanoparticles of Y2O3:Dy3+ were prepared by the solution combustion method. The X-ray diffraction pattern of the 900°C annealed sample shows a cubic structure and the average crystallite size was found to be 31.49 nm. The field emission scanning electron microscopy image of the 900°C annealed sample shows well-separated spherical shape particles and the average particle size is found to be in a range 40 nm. Pellets of Y2O3:Dy3+ were irradiated with 100 MeV swift Si8+ ions for the fluence range of 3 × 1011_3 × 1013 ions cm−2. Pristine Y2O3:Dy3+ shows seven Raman modes with peaks at 129, 160, 330, 376, 434, 467 and 590 cm−1. The intensity of these modes decreases with an increase in ion fluence. A well-resolved thermoluminescence glow with peaks at ∼414 K (Tm1) and ∼614 K (Tm2) were observed in Si8+ ion-irradiated samples. It is found that glow peak intensity at 414 K increases with an increase in the dopant concentration up to 0.6 mol% and then decreases with an increase in dopant concentration. The high-temperature glow peak (614 K) intensity linearly increases with an increase in ion fluence. The broad TL glow curves were deconvoluted using the glow curve deconvoluted method and kinetic parameters were calculated using the general order kinetic equation

Synthesis characterization and luminescence studies of 100 MeV Si 8+ ion irradiated sol gel derived nanocrystalline Y2O 3

Nanoparticles of pure yttrium oxide (Y2O3) have been prepared by sol gel method. The powder X-ray diffraction (PXRD) pattern of as synthesized sample showed the amorphous nature. The as synthesized Y2O3 powders are annealed at 500, 600, 700, 800 and 900 °C for 2 h. Y2O3 powder heat treated for 600 °C showed cubic phase and the crystallite sizes are found to be ∼13 nm. Fourier transformed infrared spectroscopy (FTIR) revealed absorption with peaks at 3434, 1724, 1525, 1400, 847, 562 and 465 cm−1. Photoluminescence (PL) of 100 MeV Si8+ ion irradiated samples shows emission with peaks at 417, 432, 465 nm. It is found that PL intensity increases with increasing in ion fluence up to ∼3 × 1012 ions cm−2 and then decreases with further increase in ion fluence. A well resolved thermoluminescence (TL) glow with peak at ∼430 K (Tm1) and an unresolved TL glow with peak at ∼538 (Tm2), 584 K (Tm3) are observed in ion irradiated samples

Ion beam induced luminescence studies of sol gel derived Y2O3:Dy3+ nanophosphors

Pure and Dy3+ doped Y2O3 are prepared by sol-gel technique. The samples are annealed at 900 °C to obtain crystalline phase. X-ray diffraction (XRD) patterns confirm cubic phase of Y2O3. The crystallites size is calculated using Scherrer formula and is found to be in the order of 29.67 nm. The particles are found to be spherical in nature and their sizes are estimated to be 35 nm by scanning electron microscope (SEM) technique. Online ionoluminescence (IL) spectra of pure and Dy3+ doped Y2O3 are recorded with 100 MeV Si8+ ions with fluence in the range 0.375-6.75×1013 ions cm-2. Undoped samples do not show IL emission for any of the fluence explored. Four prominent IL emissions with peaks at 488, 670, 767 nm and a prominent pair at 574 and 584 nm are observed in Dy3+ doped samples. These characteristic emissions are attributed to luminescence centers activated by Dy3+ ions due to 4F9/2→6H15/2, 4F9/2→6H11/2, 4F9/2→6H9/2+6H11/2 and 4F9/2→6H13/2 transitions respectively. Further, it is found that IL intensity at 574 nm decays rapidly with ion fluence. A broad and weak photoluminescence (PL) emission with peak at ~485 nm and a strong emission at 573 nm are observed in ion irradiated Y2O3:Dy3+. It is found that PL intensity increases with ion fluence up to 3×1010 ions cm-2 and then it decreases with further increase of ion fluence. This may be attributed to lattice disorder produced by dense electronic excitation under swift heavy ion irradiation. © 2015 Elsevier B.V

Synthesis characterization and luminescence studies of gamma irradiated nanocrystalline yttrium oxide

Nanocrystalline Y2O3 is synthesized by solution Combustion technique using urea and glycine as fuels. X-ray diffraction (XRD) pattern of as prepared sample shows amorphous nature while annealed samples show cubic nature.The average crystallite size is calculated using Scherrer's formula and is found to be in the range 14–30 nmfor samples synthesized using urea and 15–20 nm for samples synthesized using glycine respectively. Field emissionscanning electron microscopy (FE-SEM) image of 1173 K annealed Y2O3 samples show well separated sphericalshape particles and the average particle size is found to be in the range 28–35 nm. Fourier transformed infrared (FTIR) and Raman spectroscopy reveals a stretching of Y–O bond. Electron spin resonance (ESR) shows V− center, O2 − and Y2+ defects. A broad photoluminescence (PL) emission with peak at ~386 nm is observed when the sample is excited with 252 nm. Thermoluminescence (TL) properties of γ-irradiated Y2O3 nanopowder are studied at a heating rate of 5 K s−1 . The samples prepared by using urea show a prominent and well resolved peak at ~383 K and a weak one at ~570 K. It is also found that TL glow peak intensity (Im1) at ~383 K increases with increase in γ-dose up to ~6.0 kGy and then decreases with increase in dose. However, glycine used Y2O3 shows a prominent TL glow with peaks at 396 K and 590 K. Among the fuels, urea used Y2O3 shows simple and well resolved TL glows. This might be due to fuel and hence particle size effect. The kinetic parameters are calculated by Chen's glow curve peak shape method and results are discussed in detai

Thermoluminescence Studies of γ-Irradiated Nanocrystalline Y3Al5O12

Nanocrystalline yttrium aluminum garnet (Y3Al5O12) is synthesized by combustion technique. The X-ray diffraction (XRD) pattern of 900 °C annealed sample revealed a cubic structure. The average crystallite size is found to be 20.5 nm. γ-irradiated Y3Al5O12 exhibits two thermoluminescence (TL) glows: a prominent one with a peak at ∼410 K and another one with a peak at ∼575 K. It is found that the TL glow peak intensity at 410 K increases, while its glow peak temperature is almost steady with an increase in the γ-dose. The effect of the heating rate on the TL glow curve is studied. It is found that Tm1 shifts towards higher temperature region while the Im1 decreases with an increase in the heating rate. The TL glow curves are analyzed by Chen's peak shape method and the TL parameters are estimated

SHI induced thermoluminescence properties of sol-gel derived Y2O3:Er3+ nanophosphor

Nanocrystalline erbium doped yttrium oxide (Y2O3:Er3+) was synthesized by the sol-gel technique using citric acid as complexing agent. The synthesized samples were characterized by X-ray diffraction (XRD), Field emission scanning electron microscope (FE-SEM) techniques for phase-purity and microstructure. Er3+ doped Y2O3 crystallizes in cubic phase with an average crystallite size of 24.3 nm. The pellets of Y2O3:Er3+ were irradiated with 100 MeV swift Si8+ ions with fluence in the range of 3×1011 - 3×1013 ions cm-2. Three well resolved thermoluminescence (TL) glows with peaks at ~422, 525 and 620 K were observed in Er3+ doped Y2O3 samples. It was observed that the TL intensity was found to increases with increasing Er3+ concentration up to 0.4 mol% in Y2O3 and thereafter it decreases with further increase of Er3+ concentration. Also, the intensity of low temperature TL glow peak (~422 K) increases with increasing ion fluence up to 1×1012 ions cm-2 and decreases with further increase of ion fluences. The TL trap parameters were calculated by glow curve shape method and the deconvoluted glows were exhibit of second order kinetics. Copyright © 2015 VBRI press. - See more at