P. Psuja

Rare-earth doped nanocrystalline phosphors for field emission displays

The cathodoluminescence properties of rare-earth (RE = Ce, Eu, Tb) doped nanocrystalline phosphors (Y2O3, Y3Al5O12) were investigated. Their structure and morphology were determined and correlated with optical properties. The effect of grain sizes on emission yield of RE doped nanophosphors has been investigated. A possibility of application of RE doped nanophosphors for efficient field emission display (FED) devices has been discussed.

Influence of concentration and sintering temperature on luminescence properties of Eu3+:SnO2 nanocrystallites

Abstract The nanopowders of SnO2 doped with different Eu3+ concentrations were synthesized using the modified Pechini method. The Eu3+ concentrations were high above solubility limit. The average size of crystallites was controlled by the sintering temperatures. The structure and the morphology of obtained powders were examined using the XRD (X-ray diffraction) and TEM (transmission electron microscopy) analyses. The Eu2Sn2O7 phase separation was observed at relatively high concentration of Eu3+ ions. The ZnS:Ag micropowders were mixed with the Eu3+:SnO2 powders and their normalized emission was used to measure a relative efficiency of Eu3+:SnO2. The photoluminescence spectra of mixed powders were measured in function of Eu3+ concentration and average size of nanocrystallites. The reference peak method was used for comparison of intensities of the samples and selection of optimal one. The influence of the average grain size and Eu3+ concentration on the phosphors efficiency was discussed. The presented results confirmed the rightness of synthesis of the Eu3+:SnO2 in form of nanocrystalites with relatively high Eu3+ concentration.

Cathodoluminescent properties of Tb3+-doped yttria nanocrystallites

The Tb3+-doped Y2O3 nanopowders were synthesized using the modified Pechini method. The average size of nanocrystallites was controlled by different sintering temperatures. The structure and morphology of obtained nanopowders were examined using the XRD and SEM analyses. The Cr:Al2O3 was mixed with Tb3+:Y2O3 powders and its normalized emission was used to measure a relative intensity of Tb3+:Y2O3. The mixtures were electrophoretically deposited on ITO-glass slides. The cathodoluminescence spectra of obtained layers were recorded and analysed. The discussion over an influence of average grains size on phosphor efficiency was presented.

Non-thermal plasma-driven synthesis of Eu3+:Y2O3 nanosized phosphors

Abstract The synthesis of nanosized phosphors by using the non-thermal plasma-driven method is presented. The method allows to control the average grain size of nanocrystals. The synthesis of Eu3+-doped Y2O3 nanocrystalline phosphors at water solution of nitrates is described. The average sizes of nanocrystals were controlled by sintering temperature. Their structure, morphology, and luminescent properties were investigated.

Fabrication, luminescent properties and possible photonics application of Eu:Y 2 O 3 nanoparticles

The Eu3+ doped yttria nanoparticles were synthesized by modified Pechini method. Different values of sintering temperature were applied during synthesis process. XRD patterns were taken to examine the structure and estimate the average grains size of obtained nanocrystals. The photoluminescence of obtained powders was measured. Then powders were electrophoretically deposited on ITO-glass slides. Cathodoluminescent spectra of deposited layers were taken and compared. Also the luminescent decay times for 5D0rarr7F2 were recorded. The influence of sintering temperature on cathodoluminescent and photoluminescent properties of europium doped Y2O3 nanocrystallites and possible application of obtained material will be discussed.

Synthesis and characterization of indium-tin oxide nanostructures

The nanocrystalline indium-tin oxide (ITO) was synthesized by the modified Pechini method. The thermal analysis (TGA and DTA) of sintering process were carried out for 3 samples with a different substrates ratio. The structure and morphology of obtained powders were determined by the XRD measurement and TEM images. Average grains size of nanocrystals was estimated from bordering of the diffraction peak using a Scherrers equation. The influences of sintering temperature as well as conditions of synthesis on average grains size were observed. In order to determine the conductive properties of obtained nanopowders the ITO layers were fabricated using the spin-coating method. The layers resistance was measured by the four points method. Also the optical transmission of obtained layers was measured and compared. An influence of the conditions of synthesis on the properties of obtained materials and their application will be discussed in this work.

Fabrication, properties and possible applications of pure and Eu 3+ doped SnO 2 and In 2 O 3 /SnO 2 (ITO) nanocrystallites

The indium tin oxide and europium doped and undoped tin dioxide nanoparticles where synthesized by modified Pechini method. The powder X-ray diffraction (XRD) and transmission electro-microscopy (TEM) analyses where done in order to determined the structure and morphology of obtained materials. To determine the optical and electrical properties of the samples on the base of obtained powders thin films where fabricated by spin-coating method. The emissive properties of Eu3+:SnO2 powders sintered in different temperatures were determined earlier. The potential applications of obtained materials have been shown and discussed in this work.

Fabrication and optical properties of selected coreshell structures with nanocrystalline rare-earth doped phosphors coated with SiO 2 submicron particles

In the first step silica submicron particles were prepared by the sol-gel method. Then obtained cores were occluded with a precursor of terbium doped yttrium aluminum garnet (YAG). The same procedure was repeated for europium doped tin dioxide. The morphology and structure of obtained shell materials were determined by powder X-ray diffraction (XRD) and transmission electro-microscopy (TEM) analyses. Luminescent properties of obtained structures were determined. Possible applications of presented materials are discussed.

Rare-Earth Doped Nanocrystalline Phosphors for Field Emission Display Application

The nanocrystalline powders of yttrium aluminum garnet (YAG) and yttria (Y2O3) doped with rare earth ions (Tb3+, Eu3+, Ce3+) were obtained by modified Pechini method. X-ray powder diffraction (XRD) patterns were taken to confirm the structure of obtained materials. Average size of nanograins was estimated using the Scherrers equation. Then powders were electrophoretically deposited on ITO-glass slides. The cathode composed of carbon nanotubes was fabricated in the same manner. Low-voltage cathodoluminescent spectra was taken and analyzed and a possibility of application of RE doped nanocrystalline YAG and yttria in the field emission displays (FEDs) was discussed

The concept of a new simple low-voltage cathodoluminescence set-up with CNT field emission cathodes

The new, simple low-voltage cathodoluminescece set-up was designed and plotted. The set-up was designed on the base of field emission light emitting device with carbon nanotube (CNT) cold cathode and anode covered by layer of nancrystalline phosphor. The concept of set-up allowed for measuring of emissive properties of even 8 different samples in a very short time. The samples are placed in the vacuum chamber and the luminescent spectra are recorded using outside placed fiber spectrophotometer. The pressure in the set-up is controlled by vacuum sensor. The opportunities and application of presented conception of set-up will be discussed.