Relation between structural properties of Pr3+-doped yttria-stabilized zirconia nanopowders and their luminescence efficiency (original) (raw)

Unique sharp photoluminescence of size-controlled sonochemically synthesized zirconia nanoparticles

The present study explores the features of tetragonally stabilized polycrystalline zirconia nanophosphors prepared by a sonochemistry based synthesis from zirconium oxalate precursor complex. The sonochemically prepared pristine zirconia, 3 mol%, 5 mol% and 8 mol% yttrium doped zirconia nanophosphors were characterized using thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS) and photoluminescence spectroscopy (PL). The reaction mechanism of formation of zirconia nanophosphors is discussed in detail. The probable sonochemical formation mechanism is being proposed. Stabilization of tetragonal phase of pristine zirconia even at room temperature was effectively established by controlling the particle size using ultrasonic waves. Improved phase purity and good surface morphology of the nanophosphors is being achieved via sonochemical route. FE-SEM micrographs reveal that the nanoparticles have uniform spherical shape and size. The narrow particle size distribution (15–25 nm) of the zirconia nanoparticles was found from FE-SEM statistical analysis and further confirmed by TEM. Zirconia nanophosphors exhibit a wide energy band gap and which was found to vary with yttrium dopant concentration. The highlight of the present study is the synthesis of novel nanocrystalline ZrO2 and Y-ZrO2 phosphor which simultaneously emits extremely sharp as well as intense UV, violet and cyan light on exciting the host atom. The yttrium ion dopant further enhances the photoluminescence property of zirconia. These nanocrystalline phosphors are likely to have remarkable optical applications as light emitting UV-LEDs, UV lasers and multi color displays.

Comparison of ZrO2:Y nanocrystals and macroscopic single crystal luminescence

Journal of Physics: Conference Series, 2007

The luminescence spectra of a tetragonally structured ZrO 2 :Y single crystal and nanocrystals were compared. It was found that the number of luminescence centers contributed to the spectra. The excitation of luminescence within the band gap region led to different luminescence spectra for the single crystal and nanocrystal samples, whereas recombinative luminescence spectra were the same for both samples. The origin of this difference is that in the nanocrystals, even under excitation within the band gap, charge carriers were created. Zirconium-oxygen complexes distorted by intrinsic defects were proposed to be the luminescence centres responsible for the wide luminescence band observed.

Influence of fluorination on structure and luminescence of ZrO 2 :Eu nanocrystals

2017

The set of solid solutions ZrO 2 :0.005Eu 3+ /xF À (x = 0, 0.02, 0.04, 0.08, 0.10) was prepared via solid-state route. Synthesized powders were studied by means of XRD powder analysis, scanning electron microscopy and luminescence spectroscopy. The XRD patterns for all co-substituted samples are a composition of the monoclinic and cubic phases of zirconia. The products are crystallized in a compact form with an average size of particles about 50-150 nm. All studied samples at room temperature show in their PL spectra both wide band of the host-related emission (l max % 480 nm) and sharp peaks of the 5 D 0-7 F J (J = 0-4) radiation transitions in Eu 3+ ions under excitation with l ex = 393 nm. The total intensity of the Eu 3+ luminescence increases more than 6 times with fluorine content, x, increasing up to 0.08. Possible mechanisms of the luminescence behavior are discussed.

Visible light emission under UV and IR excitation of rare earth doped ZrO2 nanophosphor

Optical Materials, 2005

Strong visible emission under UV (320 nm) and IR (967 nm) excitation on ZrO 2 :Sm 3+ and ZrO 2 :Er 3+ nanophosphors were obtained and the concentration effect on the luminescence and crystalline structure is reported. Experimental results shows that phase composition depend on the ion concentration. The visible emission obtained under UV excitation is produced by the transitions 4 G 5/2 ! 6 H 5/2,7/2,9/2 of Sm 3+ through a non-radiative energy transfer process from the host to the active ion. Energy transfer and quenching effect due to ion concentration was confirmed by measuring the fluorescence decay time. Green (545 nm) and red (680 nm) emissions bands were observed under IR excitation troughs an upconversion process. It was proved that visible emission for both nanophosphor could be tuned by controlling the ion concentration. The nature of this behavior is discussed taking into account the phase composition for ZrO 2 :Sm 3+ and two photon absorption and cross-relaxation process was considered for ZrO 2 :Er 3+ nanophosphor.

Preparation, characterization and optical properties of ZrO2:Er3+, Yb3+nanomaterials

Journal of physics, 2009

Luminescent nanomaterials from lanthanide are one of most promising materials for applications in medical diagnostics. In this paper, we present for the first time the ZrO 2 nanomaterials with capsule like nanostructure with the sizes of 150 nm in length and 50 nm in width. These nanocapsule like ZrO 2 doped with Er 3+ , Yb 3+ ions were prepared by soft template methods. Morphological characterization of nano -ZrO 2 :Er 3+ , Yb 3+ was performed by using FESEM, X-ray diffraction, micro Raman. Up conversion luminescence and photoluminescence have been also studied with IR-laser excitation at 940 nm and UV excitation at 365 nm.

Effect of Annealing on the Crystal Structure and Microstructure of Pr Doped ZrO2-Y2O3Nanocrystals

Acta Physica Polonica A, 2010

Rare-earth doped nanocrystalline yttria-stabilized zirconia (YSZ, ZrO2-Y2O3) is, recently, a subject of studies because of its luminescent properties. The luminescence may be strongly influenced by the crystal structure and microstructure of the material. In this work, the X-ray diffraction study for Pr doped YSZ nanocrystals is presented. The phase composition dependence on the Y2O3 content and on heat treatment conditions is quantitatively determined using the Rietveld method and the similarities and differences between the present data for doped samples and earlier reported data for undoped material are discussed. A formation of high symmetry phases (cubic and tetragonal) is observed for high yttria content in agreement with general tendencies observed in literature for undoped samples.

Luminescence of Nanosized ZrO2 and ZrO2: Pr Powders

Solid State Phenomena, 2003

The time-resolved luminescence from different size ZrO 2 and ZrO 2 :Pr nanocrystals was studied. The pulsed electron beam (270 keV, 10 ns) was used for luminescence excitation. The luminescence band peaking at 2.8 eV is suggested to be of intrinsic origin. Luminescence intensity and decay kinetics depends on the nanocrystal size. The large size nanocrystals show more intense luminescence than small sized nanocrystals. This dependence arises due to nonradiative decay of electronic excitations at nanocrystal surface. The luminescence intensity from ZrO 2 :Pr nanocrystals is much lower than from undoped ZrO 2 nanocrystals. The surface area analysis was undertaken by BET (Braunaver, Emmet, Teller) method (Model Gemini 2360, Micromeritics Instruments Corp), using nitrogen as an adsorbate. The specific surface area (S) was determined for each powder. The average grain size (F) of nanocrystals was calculated

Low temperature synthesis of pure cubic ZrO2 nanopowder: Structural and luminescence studies

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

Luminescence of Nanosized ZrO₂ and ZrO₂: Pr Powders

Solid State Phenomena, 2003

Surface Chemistry of Zirconia Nanopowders Doped with Pr 2 O 3: an XPS Study

Zirconia nanopowders of tetragonal crystallographic structure doped with Pr 2 O 3 were prepared by the microwave-assisted hydrothermal synthesis and coprecipitation method. The surface compositions were studied by X-ray photoelectron spectroscopy. The nanopowder particles appear to be inhomogeneous in their structure: for the surface region an enrichment with praseodymium is detected by X-ray photoelectron spectroscopy measurements. This allows the assumption of a core-shell-like structure of single nanopowders particles. The X-ray photoelectron spectroscopy studies confirm also Zr 4+ and Pr 3+ as main oxidation states of zirconium and praseodymium in the studied compounds.