Materials prepared, with Publications, 1998-2006


ZnS ; submicron, nano-particles; semiconductor, luminescent.
ZnS:Mn2+ ; Green phosphor
CdS ; submicron, nano-particles; semiconductor

Gd2O3:Eu3+ ; Red Phosphor,
612 nm. As-prepared 800-C have sharp peaks of cubic phase, and the crystallinity increased with increasing reactor temperature up to 1400-C.
Absorbed excitation: 220 nm to 300 nm, and the maximum was near 255 nm.
The optimum brightness was obtained at a Eu doping concentration of 10 at.%.

Y2O3:Eu3+ ; Nanoparticles and Submicron, Red Phosphor. Emission 612 nm. As-prepared particles above 600 degrees C had good crystallinity.

SrTiO3:Pr3+, Al3+ (Pr3+, Al3+ doped strontium titanate)
Red Phosphor, submicron particle, -620 nm PL emission (with 365 nm excitation)

Y2SiO5:Tb ; Green Phosphor, 538 nm.
Below 1100 deg-C: poor crystallinity, 1200 deg.C: sharp crystallinity.
Absorbed excitation : 220 to 325 nm, and the maximum was near 240 nm.
Optimum brightness = doping of 4 at%. Tb.
PL intensity of as-prepared particles at 1200 degrees C was 96% in comparison with
maximum intensity of calcined particles.

Ce-Tb-Mg-Al-O system, Ce1-xTbxMgAl11O19 ; Green phosphors.
As-prepared particles at 1700 degreesC had higher crystallinity and photoluminescence properties compared with those of post-treated particles.

LED related phosphor, Yttrium Aluminum Garnet (Y3Al5O12, YAG)
YAG:Ce; Ex.470nm, Em.528 nm, Green phosphor
Phase-pure YAG with high crystallinity were obtained after annealing (1300 deg.C etc.).
Excitation: 403-510 nm (max. near 470 nm).
Broad emission peaks 480-650 nm (max. 528 nm).
Best doping value: 1 at% Ce.

YAG:Tb; Green phosphors
Particles without using flux had higher crystallinity than that of the commercial products and maintained its sphericity (0.94 micrometer size)
Non-aggregation characteristics even after post-treatment at 1400 degrees C for 5 h.
Maximum brightness; doping of Tb was 2.5 at.% and post-treatment temperature was 1400 deg. C.
PL brightness of particles post-treated at 1400 degrees C was in the same order comparing to that of the commercial product.

Zn2SiO4:Mn ; Green phosphor
Submicron spherical particles. Pure willemite was formed at 1000-1300 deg.C.
Emission band in the 525 nm when excited by 254 nm light.

LaPO4:Ce,Tb ; Green Phosphor (543nm)
Submicron particles, comparable-PL with the commercial one, max.PL= 1550-C.

Y2SiO5:Ce3+ ; Blue Phosphor
Annealing above 1000 deg.C had a clear crystallinity of Y2SiO5.
Crystal structure changed from X-1 to X-2 type after annealing above 1200 degrees C.
Mean size of the particles 0.5 to 1.4 micrometer.
PL intensity and crystallinity of particles increased as the particle size and preparation temperature were increased.
Emission of blue light was observed after annealing above 1000 degC.
Excitation: 366 nm.
PL spectra particles annealed below 1100 degrees C had maximum values at 450 nm,
and shifted to the smaller wavelengths after annealing above 1200 degrees C.
Particles annealed above 1400 degrees C exhibited intensities higher than those of particles produced commercially.
J. Solid State Chem. 1999

BaMgAl10O17:Eu2+ (BAM:Eu) ; Blue phosphors
As-prepared 1200 degrees C: amorphous phase, but at 1500 and 1700 deg.C: good crystallinity.
Particles which were directly prepared by spray pyrolysis had higher PL intensities
than these of post-treated particles.
BAM:Eu also can be produced by using our Polymer-supported Solution Synthesis.

(Y,Gd)3Al5O12:Ce ; Yellow (Yellow phosphor.)

SiO2:Eu3+, Red Luminescent
Nanostructured Spheres (sub-micron sized particles).

Luminescent Polymer Electrolytes.
ZnO quantumdot (below 10 nm) in Polymer (Polyethylene Glycol),
Excitation 325-355 nm, Emission 492-525 nm. Green.

ZnO nanoparticles (size 26-100nm)

ZnO:Eu2+ (red emission) and ZnO:Eu3+ (blue emission)

Nickel, Ni; submicron and nano-particles
NH3. H2O and NH4BCO3 in the preparation of Ni particles from NiCl2. 6H(2)O.
Ni could also be obtained in the absence of H-2 in the carrier gas.
In the latter case, it was shown that NH3 was primarily responsible for Ni formation.

Ag-Pd ; Au-Pd ; Au-Ag

ZrO2, SiO2
NiO; submicron and nano-particles

(Ba1-xSrx)TiO3 (x=0.5)
BaTiO3, submicron and nano-particles, 30 – 360 nm.
CeO2 (nanoparticle, size 10-100nm)
TiO2 (below 100 nm, nanoparticle)

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