Afterglow and thermoluminescence of ZrO2 nanopowders

Materials Letters, 2000

An unpublished high temperature thermoluminiscent signal centered at 4008C induced by UV radiation of pure tetragonal zirconium oxide, is reported. Zirconia samples were prepared by the sol-gel method and annealed at 5008C to produce the Ž. tetragonal phase and at 10008C to obtain the monoclinic phase. Experimental results show that the thermoluminiscent TL glow peak depends on both the crystalline structure and crystallite size. The high temperature peak is 2708C shifted up with respect to the main peak of the monoclinic phase. To our knowledge, this is the highest temperature TL signal reported for zirconia samples, opening new possibilities for the design of high temperature dosimeters.

Journal of Materials Science, 2014

Nanocrystalline ZrO 2 materials were prepared by sol-gel method combining different W = [H 2 O]/[ZTB] ratios (ZTB: zirconium tetrabutoxide) with 600, 800, and 1000°C annealing temperatures, yielding diverse phase compositions. A lower post-synthesis annealing temperature (600°C) favored the t-ZrO 2 tetragonal phase while higher temperatures (800 and 1000°C) yielded the monoclinic one (m-ZrO 2). Depending on the preparation conditions, mixed structure materials are readily obtained. The luminescence activator in the undoped ZrO 2 is assumed as trivalent titanium and emission bands are assigned to the 3d 1 (e g) ? 3d 1 (t 2g) transition. Due to weaker crystal field in m-ZrO 2 form, the Ti 3? emission band is red-shifted from 410 nm in t-ZrO 2 to 500 nm. The luminescence intensity of the t-ZrO 2 form is quenched at higher temperature than that of m-ZrO 2 , indicating higher activation energy and smaller Stokes shift. The undoped ZrO 2 excitation seems to involve photoionization of Ti 3? to Ti IV. Simultaneously, the freed electron is trapped to the oxygen vacancies (F ?? centers) created by Ti 3? /Ti IV charge compensation, so this can be considered as a metalto-host/ligand charge transfer. Since most of the excitation results in immediate emission, the traps are probably very shallow though deeper ones leads to the persistent luminescence from the undoped ZrO 2 .

Journal of Materials Science: Materials in Electronics, 2018

White and yellow light were obtained from ZrO 2 :Dy 3+ nanocrystals which were synthesized by the solvent evaporation technique. The crystalline structure was studied by X-ray diffraction, resulting in a tetragonal and monoclinic mixture phases of ZrO 2 when the powders were annealed at 600 °C and the zirconia monoclinic phase when they were thermal treated at 1000 °C. By means of atomic force microscopy images was observed that the synthesized powders are constituted by nanocrystals about 20 nm for the samples annealed at 600 °C, whereas samples annealed at 1000 °C were constituted by crystals about 135 nm, these features were confirmed by TEM images. Luminescence properties were analyzed by means of photo and cathodoluminescence; exhibiting emissions in the white light region of the chromatic diagram. In the case of photoluminescence white-warm color (x = 0.35, y = 0.37) was observed, which is close to pure white color; while for cathodoluminescence the emission was yellowish with coordinates (x = 0.39, y = 0.39) in the chromatic diagram. PL decay time measurements were carried out; a lifetime of 0.66 ms was found. In addition, the PL quantum efficiency was measured; the obtained value was as high as 45%.

2014

We present preparation of pure cubic zirconia (ZrO 2 ) using one step solution combustion synthesis. We have achieved pure cubic phase devoid of any additional phases without calcination. PL and TL properties are studied and the relation between defects and emission behavior is explored. TL kinetic parameters have been calculated and correlated with the different traps created. ZrO 2 show linear TL response and do not saturate even at high c-dose of 5 KGy. g r a p h i c a l a b s t r a c t

Journal of Physics and Chemistry of Solids, 2011

The dependence of structural properties and optical constants on annealing temperature of a 2-((1,2-bis (diphenylphosphino)ethyl)amino) acetic acid-methyl red-monochloro zinc dihydride (DPEA-MR-Zn) as a novel organic semiconductor thin film was studied. The DPEA-MR-Zn thin film was deposited on silicon substrates using the spin coating technique. The as-deposited film was annealed in air for 1 h at 150, 175 and 205 C. The XRD study of DPEA-MR-Zn in its powder form showed that this complex is mere a triclinic crystal structure with a space group P-1. In addition, the XRD patterns showed that the asdeposited thin films were crystallized according to the preferential orientation [(214), (121), (026), (302), (122) and (114)]. Moreover, two additional peaks (221 and 247) were shown at 2q nearly 30 , and 69 , where, the more annealing temperature, the more the intensity of the two peaks. In addition, it was noticed that the grain size had a remarkable change with an annealing temperature of the DPEA-MR-Zn thin films. The optical measurements showed that the thin film has a relatively high absorption region where the photon energy ranges from 2 to 3.25 eV. Both of WempleeDiDomenico and single Sellmeier oscillator models were applied on the DPEA-MR-Zn to analyze the dispersion of the refractive index and the optical and dielectric constants. The outcome of the study of the structural and optical properties reported here of the DPEA-MR-Zn organic semiconductor crystalline nanostructure thin film had shown various applications in many advanced technologies such as photovoltaic solar cells.

Optical Materials Express, 2012

Non-doped as well as titanium and lutetium doped zirconia (ZrO 2) materials were synthesized via the sol-gel method and structurally characterized with X-ray powder diffraction. The addition of Ti in the zirconia lattice does not change the crystalline structure whilst the Lu doping introduces a small fraction of the tetragonal phase. The UV excitation results in a bright white-blue luminescence at ca. 500 nm for all the materials which emission could be assigned to the Ti 3+ e g  t 2g transition. The persistent luminescence originates from the same Ti 3+ center. The thermoluminescence data shows a well-defined though rather similar defect structures for all the zirconia materials. The kinetics of persistent luminescence was probed with the isothermal decay curve analyses which indicated significant retrapping. The short duration of persistent luminescence was attributed to the quasi-continuum distribution of the traps and to the possibility of shallow traps even below the room temperature.

Ceramics International, 2014

Nano-and submicron-scale crystalline ZrO 2 powders with a monoclinic phase were comparatively investigated as a function of annealing temperature. The energies of defect states may change upon annealing, leading to the variations in crystallite size as revealed in X-ray diffraction and forming the excessive nano-crystallites aggregation as revealed in scanning electron microscopic images. The concomitant electronic energy states are identified by measuring photoluminescence excitation and photoluminescence spectra in UV and visible range and related with abundant oxygen vacancies as a function of annealing temperatures. The crystallites aggregation upon annealing was further manifested by the size-dependent extinction coefficients at 0.2-1.6 THz.

Ceramics International, 2009

Pure tetragonal-ZrO 2 nanopowders are prepared by a molten hydroxides method, using hydrated zirconium nitrate as the starting material at 200 8C. X-ray diffraction analysis and transmission electron microscopy observation reveal that the nanopowders exhibit poor crystalline quality. After heat treated at 400 8C for 10 h in air, the nanopowders are crystalline with size range of $10-12 nm and most of them are agglomerated. The formation mechanism of the ZrO 2 nanopowders has been proposed. The heat treated nanopowders have a BET surface area of $27.3 m 2 /g due to agglomeration. The photoluminescence of the heat treated nanopowders has been investigated at room temperature. #

Journal of Physics: Conference Series, 2010

Analysis of the thermoluminescence (TL) properties of ZrO 2 doped with Eu and Li has been conducted. Different quantities of lithium co-dopant have been added as Li 2 CO 3 to a mixture of ZrO 2 with 1wt% Er. Pellets sintered at a temperature of 1200 0 C have been prepared and the kinetic parameters of the phosphors have been studied after irradiation with UV light. It has been shown that the addition of 8 to 10 wt% of Li to the mixture of ZrO 2 with 1wt% Er yields a maximum intensity of the peaks at 65 0 C and at 105 0 C. Spectral emission and spectral sensitivity of the phosphors have been studied. The analysis applied to TL glow curves, obtained from the UV irradiated phosphors and kept after the irradiation at different times in a dark storage, revealed that the peaks at 65 0 C and 105 0 C have relatively long fading. It is concluded that the phosphors thus obtained possess a good sensitivity to the UV emission and could be appropriate phosphors for detection and quantitative measurements of UV light.

Journal of Non-Crystalline Solids, 2008

We obtained samarium-doped zirconia using two different routes. In one, atomic layer deposited thin crystalline films were doped by using ion implantation; this sample was mainly monoclinic. The other method, the skull-melting technique, yielded polycrystalline bulk zirconia containing both monoclinic and tetragonal phases of ZrO 2 . Thorough photoluminescence (PL) measurements of Sm emission in these materials were performed using pulsed laser excitation at 405, 320 and 230 nm, respectively corresponding to direct, defect-related and host-sensitized excitation. Both samples exhibited well-resolved emission series of Sm 3+ . In general, the recorded spectra may be considered as superpositions of two different sets of lines attributable to Sm 3+ centers in different crystalline phases of ZrO 2 . These results have been confirmed by time-resolved measurements, which also suggest that all emission lines originate from a common initial state ( 4 G 5/2 ) with a lifetime of about 1 ms. As expected, the host-mediated excitation leads to a prolonged decay profile attributed to the retarded energy transfer from host to guest.

Optical Materials …, 2012

Non-doped as well as titanium and lutetium doped zirconia (ZrO 2) materials were synthesized via the sol-gel method and structurally characterized with X-ray powder diffraction. The addition of Ti in the zirconia lattice does not change the crystalline structure whilst the Lu doping introduces a small fraction of the tetragonal phase. The UV excitation results in a bright white-blue luminescence at ca. 500 nm for all the materials which emission could be assigned to the Ti 3+ e g  t 2g transition. The persistent luminescence originates from the same Ti 3+ center. The thermoluminescence data shows a well-defined though rather similar defect structures for all the zirconia materials. The kinetics of persistent luminescence was probed with the isothermal decay curve analyses which indicated significant retrapping. The short duration of persistent luminescence was attributed to the quasi-continuum distribution of the traps and to the possibility of shallow traps even below the room temperature.

Journal of Radiation Research and Applied Sciences, 2015

The present paper reports the thermoluminescence (TL) properties of combustion synthesized Ti doped ZrO 2 nanophosphors the effect of annealing on TL glow curve was also studied. The structural characterizations were done by X-ray diffraction technique (XRD), composition by Fourier transformation infrared spectroscopy and surface morphology was determined by field emission gun scanning electron microscopy (FEGSEM) technique. The prepared phosphor annealed at 600 C, 700 C, 800 C and 900 C and its thermoluminescence glow curve were recorded. The heating rate effect, the thermal quenching as well as the annealing temperature of the material were optimized for the TL glow curve of the sample. The TL glow curves for different UV, gamma doses and for Ti concentration were studied. The TL glow curve of prepared samples have glow peak at 173 C. The kinetic parameters was calculated by Computerized glow curve convolution technique (CGCD) technique. Fading and reusability studies of the nanophosphor further confirmed the phosphor's suitability for radiation dosimetry. The main conclusion is that Solution Combustion Synthesis is one of the appropriate method for synthesis of Ti doped ZrO 2 nanophosphors, which is suitable for temperature sensing applications, the post-synthesis annealing regime being one of the parameters that can affect the intensity and other parameters.

Bulletin of Materials Science, 2019

In this paper, a thermoluminescence signal centred at 129 • C induced by UV radiation of Yb 3+ -doped ZrO 2 is reported. Phosphor was prepared by a solution combustion method and annealed at 600 and 900 • C to study the effect of annealing. The prepared phosphor was characterized by X-ray diffraction and scanning electron microscopy methods. Various parameters were optimized. Computerized glow curve deconvolution was employed and kinetic parameters for every deconvoluted peak were calculated. To understand the concentration quenching, a 3T1R (three trap one recombination centre) model has been proposed.

Materials Research Express, 2021

ZrO 2 and ZrO 2 : Al 3+ (× at.%) films were deposited by ultrasonic spray pyrolysis process. Luminescent films were produced from Oxychloride Zirconium Octahydrate and Aluminium Chloride Hexahydrate as precursors. Measurements of photo and cathodoluminescence were carried out doing variations on deposition temperature and doping concentration (× at.% Al 3+ ions). With the increase in substrate temperature, an overall growth of photo-cathodoluminescence intensities was perceived. Furthermore, these films presented luminescence concentration quenching with hight Al doping concentration. Chromaticity coordinates indicated blue emission from host lattice (ZrO 2 films) and cold-white emissions from ZrO 2 : Al 3+ (× at.%) films. Closest CIE coordinates to the perfect white emission were x=0.303, y=0.337. XRD patterns, measured with variations of substrate temperature, showed tetragonal phase of nano-zirconium oxide films. In addition, surface morphology characteristics for studied films are presented.