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This paper reports on swift heavy ion (SHI) induced defects that were correlated to the color tuning in Dy3+ activated Y2O3 nanocrystals for possible application in white light emitting diodes and high energy dosimetry. The optimum concentration of trivalent dysprosium (Dy3+) doped with yttrium oxide (Y2O3) was prepared by the solution combustion technique. X-ray diffraction results revealed that the obtained powder material is a single phase body center cubic structure. The transmission electron microscopy images revealed that the particles were irregular shape with an average size of 37 nm. The composition of the synthesized materials were confirmed by Fourier transformed infra-red transmittance and Raman spectroscopy. The Dy3+ doped Y2O3 upon illumination with ultraviolet light showed the characteristic greenish yellow emission of Dy3+. This greenish yellow emission was enhanced when it was exposed to 100 MeV swift Si8+ ions and the ratio between yellow and blue emission could be tuned. This is ascribed to the SHI induced electrons/holes traps and the energy transfer between the electron/hole recombination centers and activator states in the host. The life time enhancement was found to be 931.55 μs and the photometric characterization showed that SHI influences the phosphor material to achieve pure white emission for light emitting diode applications at and beyond a fluence of 1 × 1011 ions cm−2. Thermoluminescence (TL) glow curves of 100 MeV Si8+ ion irradiated samples showed three glows with peaks at 408, 467and 592 K. The prominent peak (408 K) intensity increased upto a fluence of 1 × 1011 ions cm−2. TL trapping parameters were calculated using glow curve deconvolution (GCD) technique and the obtained results are discussed in detail.

Combustion synthesized nanocrystalline holmium (Ho) doped yttrium oxide (Y2O3) was irradiated with gamma (γ) rays, 100 MeV silicon (Si8+) and 150 MeV gold (Au9+) ions to investigate the thermoluminescent (TL) properties for dosimeter applications. No changes were observed in the crystal structure of the material even after it was exposed to the high energy ion beams. The sizes of the crystallites, however, decreased. The TL glow curves of the γ-irradiated samples showed a prominent peak at 419 K with a shoulder at 493 K. TL glow curves for the Si8+ and Au9+ ion irradiated samples showed maximum peaks centred at 407 K, 660 K and 465, 509 and 640 K. The TL glow curve peak intensity of the γ-irradiated samples increased upto a 3 kGy dose and then it decreased with a further increase in the dose but the position of the glow curve peak's temperature remained constant. The TL intensity of the Si8+ and Au9+ ions irradiated samples increased upto 5 × 1010 ions cm−2 of the fluence and then it decreased with a further increase in ion fluence. The glow curves' shapes were different from that of the gamma irradiated samples, because of different TL mechanisms involved. The TL curves were deconvoluted to calculate the kinetic parameters. The activation energy and the frequency factor are in the range of 0.90 eV–1.40 eV and 7.21 × 109 − 5.83 × 1014 s−1, respectively. The synthesized material exhibited longer TL lifetimes under the 150 MeV Au9+ ions to that of the 100 MeV Si8+ and gamma irradiated samples. The results demonstrated that Y2O3:Ho3+ possesses a high resistance to defect formation even at high electronic energy depositions. After swift heavy ion (SHI) irradiation the samples exhibited radiation resistance.

Y2O3 and Y2O3:Tb3+ powders, synthesized via the solution combustion method, were studied in order to determine the effect of 100 MeV swift Ni8+ ions on the photoluminescence (PL), thermoluminescence (TL) and swift ion beam induced defects. Synthesized materials were characterized by X-ray powder diffraction, electron spin resonance, PL intensity, decay measurements and TL. Cubic structures were observed in both the pristine and ion irradiated materials. The ion irradiated materials exhibited smaller crystallite sizes than that of the pristine material. PL peaks in the visible region were identified at 485, 542, 582 and 621 nm due to the 5D4 → 7F3,4,5,6 transition of Tb3+. The PL intensity showed an increase up to 3 × 1010 ions cm−2 and then a significant decrease with a further increase in the ion fluence. The recorded time resolved PL at an ion irradiated fluence of 3 × 1010 ions cm−2, exhibited an increase in the life time of the material. TL glow curves were obtained for the samples irradiated with a swift Ni8+ ion beam. These glow curves showed a peak at 518 K with a shoulder peak at 473 K and its intensity linearly increased upto a fluence of 1 × 1011 ions cm−2. Whereas, the undoped sample showed peaks at 421 and 662 K and its intensity sub-linearly increased upto a fluence of 1 × 1011 ions −2. TL efficiency values of the Y2O3:Tb3+ sample, irradiated by a 100 MeV Ni8+ ion beam, have been measured relative to the undoped Y2O3 sample and were found to be 1.34. The Tb3+ doped sample exhibited a less fading effect under the swift heavy ion beam.

Thermoluminescence (TL) properties of 60Co gamma irradiated Sm3+ doped Y2O3 nanophosphors were investigated for possible application for high dose gamma radiation dosimetry. Sm3+ doped Y2O3 nanophosphors were synthesized by the solution combustion method. The crystalline phase was analyzed with X-ray diffraction and an average crystallite size was found to be ~20–33 nm. TL glow curves of gamma irradiated Sm3+ doped Y2O3 nanophosphors were recorded. The TL glow curves showed a prominent glow peak at ~400 K, a smaller intensity peak at 510 K and a very weak intensity glow peak at ~640 K. These glow peaks were ascribed to host defects and Sm3+ characteristic emission. The effect of Sm3+ concentration on the TL was explored and the optimum Sm3+ concentration was found to be 0.1 mol%. The number of overlapping TL glow peaks were identified from the broad TL glow curve by the thermal cleaning method. The kinetic parameters were obtained by the glow curve deconvolutions method using the general order kinetics expression. The variation of the TL intensity with dose, the effect of heating rates, repeatability and the fading effects of gamma irradiated Sm3+ doped Y2O3 nanophosphors were also studied. TL emission showed a strong green (545 nm) emission at ~400 K and a characteristic Sm3+ emission was observed at a high dopant concentration. The results obtained were favorable for the application of high dose gamma radiation dosimetry.

Lithium ions incorporated samarium doped yttrium oxide nanostructured thin films are prepared by spray pyrolysis. Glancing angle X-ray diffraction spectrum reveals the phase and crystallinity of the film. The crystallites sizes are found to be ∼50 nm. Surface morphology of the film is studied using field emission scanning electron microscope. The image appears as carved sculptures of particles with agglomeration. Fourier transformed infrared spectrum shows a sharp and wide absorption peak at 875 cm −1 . Optical absorption spectrum exhibits a prominent absorption peak at 270 nm and the corresponding energy gap is found to be ∼5.53 eV. A broad photoluminescence emission is observed in the range 560–690 nm with a peaks at 595, 608 and 622 nm and shoulders at 580, 645 and 662 nm. The films are irradiated with γ-rays in a dose range 187–563 Gy. Thermoluminescence glow curve is deconvoluted into three peaks with temperature maxima at 400, 460 and 580 K. The activation energy and frequency factor of these TL glows are found to be in the order of ∼0.58 eV and ∼10 6 s −1 respectively.

Sol gel derived nanocrystalline yttria pellets are irradiated with 120 MeV Ag 9+ ions for fluence in the range 1 × 10 12 –3 × 10 13 ions cm −2 . Pristine and irradiated samples are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy. XRD pattern of pristine Y 2 O 3 nanocrystal reveal cubic structure. A new XRD peak at 30.36° is observed in pellet irradiated with 1 × 10 13 ions cm −2 . The peak at 30.36° is corresponding to ( 4 0 2 ¯ ) plane of monoclinic phase. The diffraction intensity of ( 4 0 2 ¯ ) plane increases with Ag 9+ 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 cm −1 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 Ag 9+ ions induce phase transformation in nanocrystalline Y 2 O 3 .

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. Th...

Luminescence emission of lithium incorporated lanthanum doped yttrium oxide thin films are studied. The films were prepared by spray pyrolysis method at 375 ± 10 °C. The crystallites sizes were evaluated and found to be ~50 nm from the X-ray diffraction peak. The feature of surface morphology was obtained by field emission scanning electron microscope. Fourier transformed infrared spectrum represent absorption peak is at 875 cm−1. Optical absorption peak at 260 nm reveals the red shift in Li doped samples with energy gap 5.42 eV. Photoluminescence emissions are at 317, 390, 428 and 612 nm. Gamma-irradiated films shows TL glow peaks at 465 K and 588 K and their corresponding activation energies and the frequency factors were found to be 0.56 eV, 1.1 MHz and 0.6 eV, 0.3 MHz respectively. The incorporated Li ions played a vital role to decrease the processing temperature with the improved the morphological features.

Pure and Dy 3+ doped Y 2 O 3 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 Y 2 O 3 . 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 Dy 3+ doped Y 2 O 3 are recorded with 100 MeV Si 8+ ions with fluence in the range 0.375–6.75×10 13 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 Dy 3+ doped samples. These characteristic emissions are attributed to luminescence centers activated by Dy 3+ ions due to 4 F 9/2 → 6 H 15/2 , 4 F 9/2 → 6 H 11/2, 4 F 9/2 → 6 H 9/2 + 6 H 11/2 and 4 F 9/2 → 6 H 13/2 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 Y 2 O 3 :Dy 3+ . It is found that PL intensity increases with ion fluence up to 3×10 10 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.

Lithium ion incorporated yttrium oxide thin films have been deposited by spray pyrolysis. The phase and crystalline nature of the thin film has been studied by glancing angle X-ray diffraction. Fourier transformed infrared spectroscopy reveal the broad and sharp absorption and found with peak 875 cm−1. Solid grains in nature are seen in the image of the thin film procured by the field emission-scanning electron microscopy. The energy gap of the thin film sample has been found through the UV–vis absorption studies and found its value is ∼5.37 eV. The photoluminescence emission spectrum was recorded under the excitation wavelength of 254 nm. Photoluminescence emission spectrum reveals the peaks are at 390, 485, 525 and 598–625 nm. Gamma irradiated thin films exhibits thermoluminescent glows with peaks at 460 and 538 K. The thermoluminescence glow curves are analyzed through glow curve shape method.

Nanocrystalline Nd3+ doped Y2O3 was synthesized by sol–gel technique. Crystallite size calculated by Scherrer relation was found to be in the range 28–30 nm. Fourier transform infrared spectroscopy (FTIR) revealed Y O, OH stretching and C O bending bonds. Pellets of Y2O3:Nd3+ were irradiated with 100 MeV swift Si8+ ions and γ-rays for the fluence/dose in the range 3 × 1011–3 × 1013 ions cm−2 and 1.0_14 kGy respectively. A prominent thermoluminescence (TL) glow with peak at 527 K and a weak one with peak at 600 K were observed in Si8+ ion irradiated samples while, a prominent TL glow with peak at 393 K besides a shoulder at 434 K and a weak one with peak at 581 K were observed in γ-irradiated phosphors. The relative TL efficiency of Y2O3:Nd3+ of 100 MeV Si ion beam to γ-rays of 60Co and is found to be 0.059. The TL kinetic parameters were calculated using Chen’s peak shape method and the results obtained are discussed. Y2O3:Nd3+ was observed for its use in space dosimetry application.

Nanocrystalline erbium doped yttrium oxide (Y2O3:Er 3+ ) 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. Er 3+ doped Y2O3 crystallizes in cubic phase with an average crystallite size of 24.3 nm. The pellets of Y2O3:Er 3+ were irradiated with 100 MeV swift Si 8+ ions with fluence in the range of 3×10 11 - 3×10 13 ions cm -2 . Three well resolved thermoluminescence (TL) glows with peaks at ~422, 525 and 620 K were observed in Er 3+ doped Y2O3 samples. It was observed that the TL intensity was found to increases with increasing Er 3+ concentration up to 0.4 mol% in Y2O3 and thereafter it decreases with further increase of Er 3+ concentration. Also, the intensity of low temperature TL glow peak (~422 K) increases with increasing ion fluence up to 1×10 12 ions cm

Lanthanum aluminate (LaAlO3) is synthesized by solution combustion method and the resultant powder is annealed at 900°C for 2 hours. X-ray diffraction (XRD) pattern confirms the rhombohedral structure LaAlO3 with space group R3¯c. γ-irradiated nanocrystalline lanthanum aluminate gives two prominent TL glow with peaks at 399 and 639 K and weak one at 547 K. TL intensity at 399 K increases up to 9.0 kGy and then decreases with increasing γ-dose. TL emission shows at 650 nm and 736 nm is attributed to the charge transfer from oxygen to metal ions. The glow curves are analyzed and the trap parameters are calculated by glow curve deconvoluted technique.Lanthanum aluminate (LaAlO3) is synthesized by solution combustion method and the resultant powder is annealed at 900°C for 2 hours. X-ray diffraction (XRD) pattern confirms the rhombohedral structure LaAlO3 with space group R3¯c. γ-irradiated nanocrystalline lanthanum aluminate gives two prominent TL glow with peaks at 399 and 639 K and weak one at 547 K. TL intensity at 399 K increases up to 9.0 kGy and then decreases with increasing γ-dose. TL emission shows at 650 nm and 736 nm is attributed to the charge transfer from oxygen to metal ions. The glow curves are analyzed and the trap parameters are calculated by glow curve deconvoluted technique.

Europium-doped yttrium oxide thin films have been deposited by a spray pyrolysis method. The crystallite sizes are calculated to be ~50 nm using Scherrer׳s formula. Fourier transformed infrared spectroscopy (FTIR) reveals broad absorption with peak at 875 cm −1 . Surface morphology and elemental composition of the thin films are studied by a field-emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray spectroscopy (EDS). The energy gap ( E g ) of the thin film sample is found to be ~5.37 eV. The film exhibits photoluminescence (PL) emission over 525–550 nm, 585–601 nm, 612 nm and 620–632 nm under the excitation of 240 nm. Gamma (γ)-irradiated films exhibit two well-resolved thermoluminescent (TL) glows with peaks at 460 and 570 K. The TL glow curves are analyzed by a glow curve shape method. The activation energy and the frequency factor are found to be, respectively, ~0.6 eV, ~3×10 6 s −1 for 460 K and ~0.53 eV, ~46.72×10 3 s −1 for 570 K.

Nanocrystalline yttrium oxide (Y2O3) is synthesized by low temperature sol-gel technique and synthesized material is annealed at 900°C. The annealed β-rayed Y2O3 two TL glows with prominent peak at 407 K and weak glow peak at 643 K were observed in all irradiated samples. It is found that TL glow peaks intensity linearly increases with increase in β-dose from 0.813 – 40.625 Gy. The TL kinetic parameters are calculated using glow curve deconvoluted (GCD) method. The TL glows exhibits general order kinetics. Intense optical stimulated luminescence (OSL) is observed in the Y2O3 sample. These material exhibits linearity and reproducibility and hence, it suggests that this material may be used as dosimetric applications.

Europium doped Y2O3 nanophosphor has been prepared by solution combustion method. The obtained phosphors were characterized by powder x-ray diffraction (PXRD).It reveals that the cubic crystalline phase of the material with an average crystallite size of 21 nm. Photoluminescence (PL) excitation spectra of gamma irradiated nanophosphors were recorded under the emission wavelength of 611 nm. PL excitation spectra reveal the distinct peaks at 252, 301, 321, 396 and 466 nm. Meanwhile, PL emission peaks at 534, 552 – 592, 611, 629-645, 687 and 710 nm were observed for excitation wavelength of 252 nm. The excitation and emission spectra of irradiated sample exhibits low intensity compared that of un-irradiated sample and found that its intensity increases up to 4.0 kGy of gamma dose and then decreases with further increase of dosage.

Europium doped Y2O3 nanophosphors have been prepared by the solution combustion method. The prepared nanophosphors were characterized by powder x-ray diffraction (XRD). XRD revealed that the cubic phase with crystallite size in the range 25–37 nm formed. Surface morphology of the samples was studied by field emission scanning electron microscopy and the particles were observed as spherical in nature, having an average size ~30 nm. The electron spin resonance spectrum of the irradiated nanophosphor exhibited a signal having peaks at g = 2.1646 and 2.0035 which are attributed to and defect centers, respectively. Thermoluminescence (TL) emission showed a strong red (611 nm) emission at 417 K. The prominent TL glow (417 K) peak exhibited low fading, good reproducibility and linear dose response in the range 0.01–2.0 kGy. This behavior is favorable for TL dosimetry applications. The Y2O3:Eu3+ nanophosphor has prodigious potential as a dosimeter to be use for monitoring high dose ionizing radiation fields.