Abstract: ZnS:Cu,Cl phosphors were synthesized by high temperature (1200 °C) solid state reaction,
mechanical milling (rotation speed = 0, 75, 150, 250 and 350 r / min) and the final annealing at 750 °C for
1 h in different atmospheres (hydrogen sulfide, sealed evacuated silica tubes and Ar). The as-prepared
phosphors were characterized by X-ray powder diffraction and photoluminescence spectra. It was found
that mechanical milling led to width increases of diffraction peaks. Both the mechanical milling and
atmosphere play important roles in the photoluminescence performance of the phosphors. Some
phosphors prepared by the three-step method possess higher photoluminescence performances than the
normal one-step method. Particularly, the luminescence intensity of the phosphor milled at the rotation
speed of 75 r / min and then treated in Ar atmosphere is about one time higher than that prepared by the
normal one-step process.
Abstract: Eu-doped CaS phosphors were prepared from sulfurization of CaCO3 in H2S gas without flux.
The doping of Eu activator was conducted in two different modes: synchronous doping during
sulfurization of CaCO3 and subsequent doping by vacuumly calcinning pure CaS and Eu2O3. Comparison
of the as-prepared samples indicated that subsequent doping led to larger optimum Eu concentration and
lower red emission intensity than synchronous doping. The different luminescence properties are ascribed
to the different activator distributions in CaS host induced by different doping modes, and the uniform
distribution resulted from synchronous doping is beneficial to the luminescence of the phosphor.
Abstract: SiC films were prepared by HFCVD technique on (111) Si substrate. The composition and the
structure of the films were investigated using EDX, XRD and transient fluorescence. Results indicated the
films deposited were nanocrystalline and the calculation of the grain size gave a further confirmation. PL
measurement of the present films showed that there existed a strong ultraviolet emission at room
Abstract: Pulsed laser deposition (PLD) technique is a very powerful method for fabricating various
oxide thin films due to its native merits. In this study, gallium and nitrogen co-doped ZnO thin films
(0.1 at.%) were deposited at different temperatures (100-600°C) on sapphire (001) substrates by using
PLD. X-ray diffractometer, atomic force microscope, spectrophotometer, and spectrometer were used
to characterize the structural, the morphological and the optical properties of the thin films. Hall
measurements were also carried out to identify the electrical properties of the thin films.
Abstract: Transparent ZnO and aluminum-doped zinc oxide (AZO) thin films were prepared via the
sol-gel process on glass substrates using an alcoholic non-polyol route and spin-coater technique for film
deposition. Zinc acetate, zinc chloride, and aluminum salt used as cations source. All the undoped and
doped xerogel films were amorphous and converted into zincite structure after firing at 200 oC,
irrespective of precursor types and dopant amounts. However, the evolution of morphology,
microstructure, and texture of the gel films were strongly depended on the precursors and dopants. The
films derived from zinc chloride showed strongly preferential (002) orientation, while acetate-derived
films exhibited random orientation. On firing at 500 oC, the visible transmittances of films were 50~92%,
depending on the kinds of precursors and dopant contents.
Abstract: ZnO nanorods were prepared by a hydrothermal reaction in the presence or absence of PVP
(polyvinyl pyrrolidone). The obtained products were characterized by means of X-ray diffraction,
scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, UV-Vis
absorption (UV) spectroscopy and photoluminescence (PL) spectroscopy. The results suggest that PVP
plays an important role in the preparation of ZnO nanorods. The UV absorption spectrum showed PVP
increases the UV-shielding ability but doesn’t influence the transparency in the visible light region. A
weak UV emission at 353 nm of PL spectra exhibit the surface of ZnO nanorods is passivated and
oxygen-related defects is supplied by PVP.
Abstract: Sm2O3 optical thin films were prepared by hydrothermal method using samarium dichloride as
source material. The influence of preparation temperature on the crystallinity, morphology and optical
properties of Sm2O3 thin film were investigated. The as-fabricated thin films were characterized by X-ray
diffraction, atomic force microscopy and spectrophotometer. Results show that the prepared thin film is
Sm2O3 crystallites thin film with compact and uniform surface microstructures. Transmittance curve
displays that the Sm2O3 crystallites thin films are transparent to visible and infrared light; and possess
excellent absorbency of UV light. With the increase of deposition temperature, the crystallinity and
optical properties of the prepared Sm2O3 thin film are improved. With the increase of hydrothermal
temperature from 170 °C to 185 °C, the bandgap of the thin film increase from 2.88 eV to 2.95 eV.
Abstract: WO3 sol was prepared through the sol-gel process. Ethanol, acetone and SiO2 sol were added to
the WO3 sol. The WO3 thin films on glass substrate were obtained with the hybrid sol by the dip-coating
technique, and then were heat-treated at different temperatures for a certain time. X-ray diffractometer
and scanning electron microscope were used to characterize the crystal structure and surface morphology
of these coatings. Visible light transmittance changes of the thin films irradiated under UV light were
measured with UV spectrometer. The experimental results demonstrated that photochromic effect,
hardness and uniformity of thin films were improved when the thin films are obtained with the hybrid sol.
Abstract: This work studies the effects of microstructure and relative density on the dielectric constant of
porous silica prepared by two different techniques: gelcasting of suspension (GCS) and gelcasting of
foams (GCF). Both routes are carried out from the preparation of silica suspension containing starch
granules. In GCS route, the resultant suspensions were heated for consolidation, while in GCF route, the
suspension was foamed before consolidation. The results indicated that the dielectric constant of porous
silica was obviously determined by relative density, but scarcely influenced by microstructure. The
logarithmic fitting equation lnε = ρ·lnεs was a good model to describe the relationship between the
dielectric constant and the relative density of porous silica prepared by both GCS and GCF routes.
Abstract: Porous silica was prepared by selective leaching of metakaolinite with 20 mass% HCl solution.
The metakaolinite was derived from the 1:1 layered structure clay mineral kaolinite by firing at 600°C for
24 h. The characteristics of porous silica were studied. The content of Al2O3 in metakaolinite was sharply
changed from 45% to less than 2% after 2 h leaching. The maximum specific surface area of the leached
sample was about 350 m2/g. The average pore size is about 2 nm. The total pore volume is 0.3 ml/g. The
layer structure of kaolinite and metakaolinite is responsible for forming micropores.