Effect of Different Surfactants on the Size Control and Optical Properties of Y2O3:Eu3+ Nanoparticles Prepared by Coprecipitation Method (original) (raw)
Related papers
The Journal of Physical Chemistry C, 2009
Nanoparticles of europium doped yttrium oxide (Y 2 O 3 :Eu 3+) were synthesized by the coprecipitation method using oleic acid as a surfactant in the presence of other additives. Incorporation of additives like ethylenediaminetetraacetic acid (EDTA) and NaCl in the reaction mixture drastically affects the particle size, size homogeneity, and emission behavior of the nanophosphors. Photoluminescence emission of the nanophosphors drastically enhances and quenches on addition of NaCl and EDTA in the reaction mixture, respectively. Such emission behaviors of the nanophosphors are explained considering the nephelauxetic effect induced by the incorporated ions in the reaction solution.
Spherical-shaped Y2O3:Eu3+ nanoparticles with intense photoluminescence emission
Ceramics International, 2015
Herein we report on the crystallized nanoparticles based on Eu 3 þ -doped Y 2 O 3 with 5 mol% using citric acid as precursor. The heating temperatures were evaluated in order to obtain the best crystallized nanoparticles with size around 12 nm and with highest red intense photoluminescence emission. Nanocrystallite size was calculated by Scherrer's equation based on diffractogram of the material heated at 750 1C for 4 h, obtaining size around 8 nm. The low photoluminescence intense emissions were attributed to the presence of quenchers remaining from precursors used in the synthesis. In general the photoluminescence properties were evaluated based on emission and excitation spectra profile. Rietveld refinement was performed based on the diffractogram of the material annealed at 750 1C for 4 h, and the visualization of the cubic structure was obtained. The centered cubic crystalline structure of Y 2 O 3 was obtained and the photoluminescence properties of Eu 3 þ ion in Y 2 O 3 host lattice was verified as being dependent on the temperature of heating and C 2 and S 6 site of symmetry present in the cubic structure. CIE chromaticity diagram was obtained with x and y being 0.682 and 0.316, respectively, for material with the highest relative photoluminescence intensity.
Optical Materials, 2014
Nano-sized yttria (Y 2 O 3 ) doped with Eu 3+ powders were successfully synthesized by co-precipitation method, where the quenching concentration for photoluminescence study of Eu 3+ ions is 12 mol% which is much higher than the micro-scaled powders. The effect of changing concentration of co-dopants (Li + , Na + and K + ) along with Eu 3+ (12 mol%) is studied on optical properties of Y 2 O 3 nanoparticles. The results showed that the incorporation of these metal ions can further improve the luminescence intensity. The highest emission intensity was observed with 6 mol% of Li + , 2 mol% of Na + , and 1 mol% of K + doping in Y 2 O 3 :Eu 3+ (12 mol%) nanoparticles given by the formula (Y 0.82mol% Eu 0.12mol% Li 0.06mol% ) 2 O 3 , (Y 0.86mol%-Eu 0.12mol% Na 0.02mol% ) 2 O 3 , and (Y 0.87mol% Eu 0.12mol% K 0.01mol% ) 2 O 3 respectively. The structural, morphological and optical properties were studied by X-ray diffraction, Rietveld refinement, transmission electron microscopy, Fourier transform infrared spectroscopy, and Photoluminescence spectroscopy. XRD studies followed by Rietveld refinement confirmed the body-centered cubic structure of doped nanophosphors. All the powders were well crystallized and the emission intensity was observed to increase further from quenching concentration of Eu 12 mol% with co-doped samples.
Luminescence : the journal of biological and chemical luminescence, 2015
Europium trivalent (Eu(3+) )-doped Y2 O3 nanopowders of different concentrations (0.5, 2.5, 5 or 7 at.%) were synthesized by the sol-gel method, at different pH values (pH 2, 5 or 8) and annealing temperatures (600°C, 800°C or 1000°C). The nanopowders samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR) and steady state photoluminescence spectroscopy. The effect of pH of solution and annealing temperatures on structural, morphological and photoluminescence properties of Eu(3+) -doped Y2 O3 were studied and are discussed. It was found that the average crystallite size of the nanopowders increased with increasing pH and annealing temperature values. The Y2 O3 :Eu(3+) material presented different morphology and its evolution depended on the pH value and the annealing temperature. Activation energies at different pH values were determined and are discussed. Under ultraviolet (UV) ligh...
Morphology controlled Y2O3:Eu3+ nanophosphors with enhanced photoluminescence properties
Journal of Luminescence, 2015
Eu 3 þ doped Y 2 O 3 is prepared by a co-precipitation method using ammonium hydrogen carbonate as precipitating agent. In the present work we studied the effect of different molar concentrations of Poly vinyl pyrrolidone (PVP) and 1-Thio-glycerol (TG) as capping agents to enhance the optical and morphological properties of Y 2 O 3 :Eu 3 þ nanophosphors. In addition, variation of pH was studied to control the particle size of the synthesized product. The polymer concentration (TG and PVP) was also optimized at different pH to get higher luminescence of Eu 3 þ doped Y 2 O 3 nanoparticles (NPs). It was observed that pH of solution during synthesis and also its concentration affect the morphological and optical properties of Y 2 O 3 :Eu 3 þ . The structural, morphological and optical properties were studied by an X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy and photoluminescence spectroscopy. XRD studies followed by Rietveld refinement confirmed the bodycentered cubic structure of doped nanophosphors. It was observed that at optimized pH and polymer concentration the nanoparticles of Y 2 O 3 :Eu 3 þ have narrow size distribution and exhibited enhanced photoluminescent properties.
Luminescent properties of nano-sized Y 2O 3:Eu fabricated by co-precipitation method
Journal of Alloys and Compounds, 2010
Nano-sized yttria (Y 2 O 3 ) powders were successfully synthesized by co-precipitation method. The structure and morphology were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). All the powders were well crystallized and the grains were almost spherical with good dispersibility. The relationship between optical properties and the content of Eu 3+ and Li + ions was studied. The quenching concentration of Eu 3+ ions is 9 mol% which is much higher than the micro-scaled powders. The results also showed that the incorporation of Li + ions can greatly improve the luminescence intensity. The highest emission intensity was observed with 4 mol% Li + doped Y 2 O 3 :Eu powder ((Y 0.87 Eu 0.09 Li 0.04 ) 2 O 3 ) and the fluorescence intensity was increased by as much as 79%.
Tartaric acid-assisted sol–gel synthesis of Y2O3:Eu3+ nanoparticles
Journal of Alloys and Compounds, 2009
In the present work, Y 2 O 3 :Eu 3+ nanoparticles have been synthesized by tartaric acid-assisted sol-gel method. The advantages of low temperature solution-based process have been exploited to produce Y 2 O 3 :Eu 3+ nanoparticles. Synthesis conditions such as calcination temperature and tartaric acid concentrations are varied in order to determine the exact optimal conditions for synthesizing nanoparticles with superior optical properties. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies have been carried out to understand surface morphological features and the particle size. Crystal structure of the nanoparticles has been investigated by X-ray diffraction (XRD) technique. Nanoparticles have average crystallite size from 20 to 45 nm. The incorporation of Eu 3+ activator in these nanoparticles has been checked by luminescence characteristics. These nanoparticles have displayed red color under a UV source. The main emission peak at 612 nm corresponds to the hypersensitive transition between 5 D 0 and 7 F 2 level of Eu 3+ ions. IR analysis has also been performed for the analysis of the nanoparticles.
Particle size control of Y 2O 3:Eu 3+ prepared via a coconut water-assisted sol-gel method
Journal of Nanomaterials, 2011
Eu 3+-doped Y 2 O 3 nanoparticles were produced through proteic sol-gel technique, and the adjustment of pH was tested in order to control the particle size of the powders. A strong correlation between the initial pH and the temperature of crystallization was observed, allowing the production of particles with controlled diameter from 4 nm to 50 nm. The samples were characterized by X-ray diffraction, high-resolution transmission electron microscopy, optical microscopy and photoluminescence spectroscopy in both absorption and emission modes. A blue shift of the excitation peak corresponding to energy transfer from Y 2 O 3 :Eu 3+ host to Eu 3+ ions was observed, as the particle size was reduced from 50 to 4 nm. The suppression of a charge transfer band also resulted from the reduction of the particle size. The emission spectrum of the Y 2 O 3 : with particles of 50 nm was found to be similar to that of bulk material whereas 4 nm particles presented broadened emission peaks with lower intensities.
Optical properties of nanocrystalline Y2O3:Eu3+
Journal of Applied Physics, 2005
Optical properties of nanocrystalline red-emitting phosphor, Europium doped Yttria (Y 2 O 3 :Eu 3+), of average particle size 15 nm are investigated. The intensity of the strongest emission line at 612 nm is found to be highest in the nanocrystalline sample with 4 at. wt. % of Europium. The narrow electronic emission spectrum suggests a crystalline surrounding in this nanomaterial. We have estimated the strength of the crystal field parameter at the dopant site, which plays a crucial role in determining the appearance of the intense emission line. The equilibrium temperature of this system has also been calculated from the intensity ratio of Stokes and anti-Stokes Raman scattering. Though known for the bulk samples, our approach and consequent results on the crystalline nanomaterial of Y 2 O 3 :Eu 3+ provide a unique report, which, we believe, can be of considerable significance in nanotechnology.
Nanotechnology
Here, we report the synthesis and spectral properties of ultrathin nanodiscs (NDs) of Y 2 O 3 :Eu 3+. It was found that the NDs of Y 2 O 3 :Eu 3+ with a thickness of about 1 nm can be fabricated in a reproducible, facile and self-assembling process, which does not depend on the Eu 3+ concentration. The thickness and morphology of these NDs were determined with small angle x-ray scattering and transmission electron microscopy. We found that the crystal field in these nanoparticles deviates from both the cubic and monoclinic characteristics, albeit the shape of the 5 D 0 → 7 F J (J=0, 1, 2) transitions shows some similarity with the transitions in the monoclinic material. The Raman spectra of the non-annealed NDs manifest various vibration modes of the oleic acid molecules, which are used to stabilise the NDs. The annealed NDs show two very weak Raman lines, which may be assigned to vibrational modes of Y 2 O 3 NDs. The concentration quenching of the Eu 3+ luminescence of the NDs before annealing is largely suppressed and might be explained in terms of a reduction of the phonon density of states.