Synthesis and temperature dependent fluorescence properties of nanoscale europium doped yttria derived in presence of tween-80 and beta-alanine

A novel procedure for the synthesis of uniform europium doped yttria powder was developed. It was prepared by chemically growth-controlled method in the presence of surface modifier. A mixture of Tween-80 (polyoxyethylene (20) sorbitate) and β-alanine, was used as surface modifier. The obtained powder was pure and highly crystalline. The powder was also examined via Fourier transformation infra red (FTIR) spectroscopy to determine the presence of nitrate ions along with the powder at pre and post calcination. Thermal behavior of the powder was investigated by thermal gravimetric analysis (TGA) and differential thermal analysis (DTA). High Resolution Transmission Microscopy (HRTEM) reveals that the particle size is around 22 nm. Chemical microanalysis of europium doped yttria was made by energy dispersive spectrum analyzer (EDS) attached along with HRTEM and indicated a Y/Eu atomic ratio 2.1. The fluorescence spectra of calcined powder showed that the Eu3+ ions were in low symmetry bonding sites in the yttria structure

Carboxylic acids and esters as scaffold for cavities in porous single layer anti-reflective coatings of silica-titania with excellent optical and mechanical properties

Anti-reflective (AR) single layer of silica-titania (SiO2-TiO2) coatings were obtained from sols containing pyromellitic dianhydride (PMDA) derivatives and Ti and Si precursors on glass substrate by dip-coating method. The coatings showed very high optical quality and the transmission was improved to up to 98.5%. Furthermore, the coatings also presented good mechanical stability

Tailoring the particle size from mycrometer to nanometer scale by using a surface modifier and their size effect on the fluorescence properties of europium doped yttria

The concept of tailored interfaces has been applied to the synthesis of Eu2O3/Y2O3 powders to achieve a narrow size distribution by using a modifier. It was found that the particle size gradually decreased from 6 µm to 10 nm with an increase in concentration of the modifier from 0 to 10 wt% with respect to Eu2O3/Y2O3. Fluorescence spectra of the sample containing 10 wt% of surface modifier showed approximately a 5-fold enhancement of emission intensity of the 5D0 \u27-> 7F2 transition of Eu3+. This transition is the characteristic transition of europium for red fluorescence under UV light excitation. The concentration dependence of fluorescence in the range from 0-5 mol% Eu2O3 did not reveal any concentration quenching

Hydrothermal synthesis of nanosize alpha-Al2O3 from seeded aluminum hydroxide

α-Alumina and boehmite particles were synthesized by co-precipitation followed by a hydrothermal treatment. X-ray diffraction (XRD) indicated that α-Al2O3 was the major phase and coexisted with 4% of boehmite in the presence of the α-Al2O3 seeds. On the other hand, a single boehmite phase was obtained in the absence of the α-Al2O3 seed particles. The powder densified in the temperature range from 1050° to 1350°C. High-resolution transmission electron microscopy (HRTEM) showed that the particle size of the synthesized α-Al2O3 was 60 nm. The surface area was 245 m2/g

Influence of initial pH on the particle size and fluorescence properties of the nano scale Eu(III) doped yttria

Europium doped yttrium oxide (Eu:Y2O3) was synthesized by a chemical wet method in the presence of tween-80 and ∈-caprolactam in pH range 4-10. It has been observed that the variation in surface area, pore size, and pore volume of the final product, was strongly dependent on the initial pH of the solution. The powder with a large surface area (∼­230 m2/g) and low pore diameter (∼­16 nm) was obtained when the powder was processed at pH ∼4. The crystallite sizes of the powders processed at pH ∼4 and 10, were found to be 35 and 198 nm, respectively. The structural, chemical and thermal studies of the powders were characterized by X-ray diffraction (XRD), Fourier transformed infrared spectrophotometer (FTIR), Carbon analyzer and Thermogravimetry (TGA). High resolution transmission electron microscopic (HRTEM) study of heat treated powders showed a polygonal morphology with particle size of 40 nm when powder was derived at pH ∼­4. Observations of fluorescence suggested that the 5D0->7F2 transition within europium was found to be highly dependent on the initial pH

Microstructure investigation of reflective coatings interference multilayers produced by sol-gel method

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