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SnS nanoaprticles have been synthesized by an environmentally benign sonochemical method under multibubble sonoluminescence conditions. First, SnS nanoparticles were prepared at room temperature by reacting SnCl 2 and thioacetoamide dissolved in ethylene glycol with various ethanolamines such as ethanolamine, diethanolamine, and triethanolamine. The sonochemical reactions were operated at 20 kHz and 220 W for 5 min. Depending on the kind and amount of ethanolamines, SnS nanoparticle sizes in diameter varied within 4–15 nm range. Depending on the SnS nanoparticle size, their bandgap changed from 1.46 to 2.0 eV. These nanoparticles were characterized by a UV–vis spectrophotometer, X-ray diffraction, and high-resolution transmission electron microscopy.

S gas.The MOCVD process was carried out in the temperature range of 300-400 °C and the average grain size infabricated SnS films was about 500 nm. The optical band gap of the SnS film was about 1.3 eV which is inoptimal range for harvesting solar radiation energy. The precursor and SnS films were characterized throughinfrared spectroscopy, nuclear magnetic resonance spectroscopy, DIP-EI mass spectroscopy, elementalanalyses, thermal analysis, X-ray diffraction, and field emission scanning electron microscopic analyses.Key Words : Sn/S single precursor, SnS thin films, Solar cell, MOCVD methodIntroductionRecently, a lot of researches have focused on thin filmsolar cells as a future resource for sustainable energy. Mostof the advanced thin film photovoltaic technologies arebased on Cu(In,Ga)Se

New chromogenic probe systems for the signalling of the water content in representative water-miscible organic solvents (acetonitrile and tetrahydrofuran) were investigated. The effect of the water content in organic solvents on the complex formation of hydrazone dye with acetate ions was utilized for the signalling. The hydrazone–acetate system exhibited a pronounced chromogenic signalling behaviour that could be detected by eye in response to the changes in water content in such common water-miscible organic solvents as acetonitrile and tetrahydrofuran. Prominent colour changes were observed for up to 1 and 2% water content in acetonitrile and THF, respectively. Detection limits of the anthracene-based hydrazone–acetate system for determination of the water content in acetonitrile and tetrahydrofuran were 0.037 and 0.071%, respectively. The 7-hydroxycoumarin-based hydrazone–acetate system showed somewhat less sensitive signalling behaviour, with respective detection limits of 0.12 and 0.63% in acetonitrile and tetrahydrofuran. The designed hydrazone–acetate systems could be used as a simple and convenient chromogenic probes for the determination of the water content in representative organic solvents of acetonitrile and tetrahydrofuran.

Supported nickel catalysts with a core/shell structure of Ni/Al 2 O 3 and Ni/MgO–Al 2 O 3 synthesized under multi-bubble sonoluminescence (MBSL) conditions were tested for mixed steam and dry (CO 2 ) reforming and autothermal reforming of methane. In the previous tests, the supported Ni catalysts made of 10% Ni loading on Al 2 O 3 or MgO–Al 2 O 3 had shown good performances in the steam reforming of methane (methane conversion of 97% at 750 °C), in the partial oxidation of methane (methane conversion of 96% at 800 °C) and in dry reforming of methane (methane conversion of 96% at 850 °C) and showed high thermal stability for the first 50–150 h. In this study, the supported Ni catalysts showed good performance in the mixed and autothermal reforming of methane with their excellent thermal stability for the first 50 h. In addition, very interestingly, there was no appreciable carbon deposition on the surface of the tested catalysts after the reforming reaction.

Colloidal cadmium telluride (CdTe) quantum dots (QDs) and their nanoparticles have been synthesized by one pot sonochemical reactions under multibubble sonoluminescence (MBSL) conditions, which are quite mild and facile compared to other typical high temperature solution-based methods. For a typical reaction, and tellurium powder with hexadecylamine and trioctylphosphine/trioctylphosphineoxide (TOP/TOPO) as a dispersant were sonicated in toluene solvent at 20 KHz and a power of 220W for 5-40 min at 60 . The sizes of CdTe particles, in a very wide size range from 2 nm-30 , were controllable by varying the sonicating and thermal heating conditions. The prepared CdTe QDs show different colors from pale yellow to dark brown and corresponding photoluminescence properties due mainly to the quantum confinement effect. The CdTe nanoparticles of about 20 nm in average were found to have band gap of 1.53 eV, which is the most optimally matched band gap to solar spectrum.

Supported nickel catalysts with core/shell structures of Ni/Al 2 O 3 and Ni/MgO–Al 2 O 3 were synthesized under multi-bubble sonoluminescence (MBSL) conditions and tested for dry reforming of methane (DRM) to produce hydrogen and carbon monoxide. A supported Ni catalyst made of 10% Ni loading on Al 2 O 3 and MgO–Al 2 O 3 , which performed best in the steam reforming of methane (97% methane conversion at 750 °C) and in the partial oxidation of methane (96% methane conversion at 800 °C), showed also good performance in DRM and excellent thermal stability for the first 150 h. The supported Ni catalysts Ni/Al 2 O 3 and Ni/MgO–Al 2 O 3 yielded methane conversions of 92% and 92.5%, respectively and CO 2 conversions of 95.0% and 91.8%, respectively, at a reaction temperature of 800 °C with a molar ratio of CH 4 /CO 2 = 1. Those were near thermodynamic equilibrium values.

Lanthanide sulfates, Hydrothermal synthesis, Three-dimensional structuresTwo- or three-dimensional framework materials containing rich structural diversities are of continuous interest attributable to their technologically important properties and potential appli-cations such as catalysis, ion-exchange, adsorption, intercala-tion, and radioactive waste remediation.

Two new metal antimony oxychlorides, Sb(2)ZnO(3)Cl(2) and Sb(16)Cd(8)O(25)Cl(14), have been synthesized by solid-state reactions using Sb(2)O(3) and ZnCl(2) (or CdCl(2)) as reagents. The structures of Sb(2)ZnO(3)Cl(2) and Sb(16)Cd(8)O(25)Cl(14) have been determined by single-crystal X-ray diffraction. Both of the reported materials contain Sb(3+) cations that are in an asymmetric coordination environment attributable to their stereoactive lone pair. Sb(2)ZnO(3)Cl(2) has a novel two-dimensional layered structure consisting of distorted ZnO(2)Cl(2) tetrahedra and SbO(3) polyhedra. Sb(16)Cd(8)O(25)Cl(14) exhibits a one-dimensional structure consisting of Sb(3+)-Cd(2+)-oxide rods, Cd(2+)-chloride double chains, and isolated Cl(-) ions. Complete separation of the halophile and chalcophile moieties is observed from the reported materials. Detailed structural analysis, IR spectra, thermogravimetric analysis, ion-exchange reactions, and dipole moment calculations are presented. Crystal data: Sb(2)ZnO(3)Cl(2), orthorhombic, space group Pnma (No. 62), a = 17.124(4) A, b = 5.5598(12) A, c = 6.4823(14) A, V = 617.2(2) A(3), and Z = 4; Sb(16)Cd(8)O(25)Cl(14), monoclinic, space group I2/m (No. 12), a = 14.251(3) A, b = 3.9895(8) A, c = 21.145(4) A, beta = 97.35(3) degrees, V = 1192.3(4) A(3), and Z = 8.

CuInS2 nanoparticles were synthesized by a simple sonochemical method; First, Cu nanoparticles were prepared from CuCl2 in methanol solution by a one pot reaction through the sonochemistry under multibubble sonoluminescence (MBSL) conditions. Second, the resulting Cu nanoparticles were treated with InCl3․4H2O and CH3CSNH2 (thioacetamide) at the same MBSL conditions to synthesize In2S3-coated Cu nanoparticles in methanol solution. Then, they were transformed into CuInS2 (CIS) nanoparticles of 20 ~ 40 nm size in diameter by thermal heating at 300 o C for 2 hr. The prepared CIS nanoparticles, of which band gap is 1.44 eV, were investigated by X-ray diffractometer, UV-Vis spectrophotometer, inductively coupled plasma spectrometer, and high resolution-transmission electron microscope.

Mn 3 O 4 and LiMn 2 O 4 nanoparticles were prepared by a simple sonochemical method which is environmentally benign. First, Mn 3 O 4 nanoparticles were prepared by reacting MnCl 2 and NaOH in water at room temperature through a sonochemical method, operated at 20 kHz and 220 W for 20 min. Second, LiOH was coated onto the resulting Mn 3 O 4 under the same sonochemical conditions as above. The thickness of coated LiOH on Mn 3 O 4 obtained from the reaction ratio of 3:1 between LiOH and Mn 3 O 4 was about 4.5–5.5 nm range. Then, by heating those LiOH-coated Mn 3 O 4 particles at the relatively low temperature of 300–500 °C for 1 h, they were transformed into phase-pure LiMn 2 O 4 nanoparticles of about 50 to 70 nm size in diameter.

Experimental Section Synthesis. Pb(NO3)2 (Junsei, 99.5%), PbO (Kanto, 98.5%), PbCl2 (Hayashi, 99%), V2O5 (Junsei, 99.0%), and NaCl (Duksan, 99.0%) were used as received. Crystals of PbVO3Cl were prepared by a hydrothermal reaction method. 1.449 g (4.38 mmol) of Pb(NO3)2, 0.106 g (1.82 mmol) of NaCl, 0.113 g (0.63 mmol) of V2O5, and 5 mL of deionized water were placed in a 23-mL Teflon-lined stainless steel autoclave that was subsequently sealed. The autoclave was gradually heated to 230 o C, held for 3 days, and cooled slowly to room tem- perature at a rate of 1 o C min -1 . The products were recovered by filtration and washed with water. Powder X-ray diffraction patterns on the manually separated colorless needles, colorless blocks, and yellow rods were determined to be PbCl2, Pb(NO3)2, and PbVO3Cl, respectively. A yield of 48% based on lead was observed from the manually separated yellow rods of PbVO3Cl. Pure polycrystalline PbVO3Cl was synthesized through a stan- dard solid-state reaction technique. A stoichiometric mixture of PbO (0.653 g, 2.93 mmol), PbCl2 (0.814 g, 2.93 mmol), and V2O5 (0.532 g, 2.93 mmol) was thoroughly ground and pressed into a pellet. The pellet was introduced into a fused silica tube that was evacuated and sealed. The tube was gradually heated to 450 o C, held for 12 h, and cooled down to room temperature. The powder X-ray diffraction pattern on the resultant yellow powder indicated the material was single-phase and in a good agreement with the generated pattern from the single-crystal data. Crystallographic determination. The structure of PbVO3Cl was determined by standard crystallographic methods. A yellow plate crystal (0.02 × 0.05 × 0.22 mm 3 ) was used for single crystal X-ray diffraction. The data were collected using a Bruker SMART APEX CCD X-ray diffractometer at room

E-mail: kmok@cau.ac.krReceived August 12, 2008Key Words : Bismuth chloride, Zero-dimensional structure, Synthesis, NoncentrosymmetrySince a wide variety of materials either observed in natureor synthesized by chemists exhibit a marked preference tosymmetry, it is quite difficult to find asymmetric substances.Nonetheless, discovering noncentrosymmetric (NCS) materialsis a continuing challenge in inorganic solid-state materialschemistry field. This is mainly because acentric materialscan reveal extremely important physical properties such asdielectric behavior, ferroelectricity, piezoelectricity, pyro-electricity, and nonlinear optical (NLO) properties.

Copper gallium disulfide (CuGaS2; CGS) films were deposited on glass or ITO glass by two-stage metal-organic chemical vapor deposition (MOCVD) method, using Cu- and Ga/S-containing precursors without toxic H2S gas. First, pure Cu thin films were prepared on glass substrates by using a single-source precursor, bis(ethylbutyrylacetato)copper(II) or bis(ethylisobutyrylacetato)copper(II). Second, the resulting Cu films were processed using tris(N,N-ethylbutyldithiocarbamato)gallium(III) at 410–470 °C to produce CuGaS2 films. The optical band gap of the CGS film grown at 440 °C was about 2.53 eV. In addition, it was found that the elemental ratio of Cu and Ga elements of the CGS films can be elaborately adjusted by controlling deposition conditions on demand.

TiO2 nanoparticles were easily coated with ZnS in nano-scale through a simple one pot reaction under multibubble sonoluminescence (MBSL) conditions which can provide a very powerful and efficient coating system. The coating depths of ZnS shell were in 2–5 nm range in a core/shell type nanostructure which is very likely to be useful for the development of inorganic dye-sensitized solar cells. The ZnS-coating depths on TiO2 in this system were found to be easily controlled in nano-scale by adjusting the amount of reactants and/or the sonication time. The ZnS-coated TiO2 nanoparticles were characterized by XRD, UV–vis, EDS, and HR-TEM.

Syntheses of zinc oxide (ZnO) and ZnO-coated titanium dioxide nanoparticles under ultrasonic field at the multibubble sonoluminescence (MBSL) condition were tried in various alcohol solutions. The MBSL condition facilitates the supercritical state of liquid layer where high-energy chemical reaction in the layer around the bubble is possible. At the optimal MBSL condition in alcohol solutions containing zinc acetate dihydrate of 2.75 wt%, sodium hydroxide of 1 wt% and TiO 2 of 1 wt%, ZnO nanoparticles having the average diameter of 7 nm were synthesized first and subsequently ZnO-coated TiO 2 nanoparticles were synthesized within 10 min. The prepared particles of ZnO and ZnO-coated TiO 2 were examined by XRD, UV–vis spectrophotometer and HR-TEM.

Highly polycrystalline copper indium diselenide (CuInSe2) thin films on molybdenum substrate were successfully grown at 330 °C through two-stage metal organic chemical vapor deposition (MOCVD) method by using two precursors at relatively mild conditions. First, phase pure InSe thin film was prepared on molybdenum substrate by using a single-source precursor, di-μ-methylselenobis(dimethylindium). Second, on this InSe/Mo film, bis(ethylisobutyrylacetato) copper(II) designated as Cu(eiac)2 was treated by MOCVD to produce CuInSe2 films. The thickness and stoichiometry of the product films were found to be easily controlled in this method by adjusting the process conditions. Also, there were no appreciable amounts of carbon and oxygen impurities in the prepared copper indium diselenide films.

The ternary chalcopyrite semiconductor CuInSe2 (CIS) or related Cu(In,Ga)Se2 (CIGS) are well known materials for high efficiency thin film solar cells. In case of CIGS absorber film prepared through chemical bath deposition method, photovoltaic conversion efficiency was reported to be higher than 19%. Such high efficiency has been reached with a CdS buffer layer processed in a wet chemical bath and the CdS has been found to be best suited as a buffer layer material. However, cadmium is toxic and has a negative effect on environment. Therefore, there have been many studies to find replacement materials for cadmium sulfide. The possible candidates for the cadmium free solar cells are ZnS, In2S3, ZnSe, InxSey. Among these materials, In2S3 is nontoxic and exhibits optical and electrical properties similar to those of CdS. Also, In2S3 thin film deposited by ALCVD using In(acac)3 and H2S was reported to be an n-type semiconductor and was found to properly function as a buffer layer for the heterojunction solar cells. For the preparation of In2S3 thin films without using toxic H2S gas, various single source precursors suitable to the MOCVD process are possible. Among them, the precursors containing dialkyldithiocarbamate ligands with non-symmetrical structure are interesting since they were found to have better thermal properties compared to symmetrical ones. In this work, two single source precursors, tris(N,Nethylbutyldithiocarbamato)indium(III) and tris(2-ethylpiperidinedithiocarbamato)indium(III) (designated as In(ebdtc)3 and In(epdtc)3, respectively) were synthesized with high purity and yield. Using them, In2S3 thin films were successfully grown on various substrates, such as glass, ITO glass, and CIGS film through MOCVD process. Experimental Details

The catalytic performance of transition metal (Fe2+ or Cu2+) containing nano-sized hol low core mesoporous shell carbon (HCMSC) heterogeneous catalysts for the hydroxylation of phenol with hydrogen peroxide (H2O2) in water was investigated in a batch reactor. The metal-containing HCMSC catalyst showed higher activity than the same metal ion-exchanged zeolites. The nature of the metal and its content in the HCMSC had remarkable influence on the reaction results under the typical reaction conditions (PhOH/H2O2=3, reaction temperature=60 ‡C). Fe2+ containing HCMSC catalyst showed high catalytic activity with phenol conversion of 29%, selectivity to catechol (CAT) and hydroquinone (HQ) about 85%, H2O2 effective conversion about 70% and selectivity to benzoquinone (BQ) below 1% in the batch system.

Copper complexes have been directly incorporated into cellulose acetate (CA) and the resulting light blue colored homogeneous films of 5-20 wt.% copper acetate complex concentrations are found to be thermally stable up to200 °C. The reaction chemistry of Cu in CA has been investigated by reacting them with small gas molecules such as CO, H 2 , D 2 , O 2 , NO, and olefins in the temperature range of 25-160 °C, and various Cu-hydride, -carbonyl, -nitrosyl, and olefin species coordinated to Cu sites in CA are characterized by IR and UV/ Vis spectroscopic study. The reduction of Cu(II) complexes by reacting with H 2 gas at the described conditions results in the formation of Cu 2 O and copper metal nanoparticles in CA, and their sizes in 30-120 nm range are found to be controlled by adjusting metal complex concentration in CA and/or the reduction reaction conditions. These small copper metal particles show various catalytic reactivity in hydrogenation of olefins and CH 3 CN; CO oxidation; and NO reduction reactions under relatively mild conditions.

A series of new Ag precursors containing β-diketonate and neutral phosphite ligands were synthesized and characterized by various spectroscopic methods. These volatile precursors in liquid phase were thermally stable and quite useful in the preparation of silver thin films through bubbler-type chemical vapor deposition (CVD). In a typical case of silver (I) 1,1,1-trifluoro-2,4-pentanedionate triethyl phosphite adduct ((tfac)AgP(OEt)3) precursor, very pure silver thin films were obtained under relatively mild conditions without any appreciable amount of F, O, and P impurities. These thin films were easily converted to β-orthorhombic silver selenide by simple selenium vapor deposition method. In scanning electron microscopic analyses, the average particle size of the latter was found to increase to about 1.26 μm after gas-phase selenization reaction.

Cerium-substituted Bi4Ti3O12 (Bi3.4Ce0.6Ti3O12) thin films were prepared by using metal-organic decomposition method. Ferroelectric cerium-substituted Bi4Ti3O12 thin films were fabricated by spin coating onto a Pt/Ti/SiO2/Si substrate. The structure and morphology of the films were characterized using x-ray diffraction and scanning electron microscopy. The Bi3.4Ce0.6Ti3O12 (BCeT) thin films, which were annealed from 550 to 700 °C for 1 h, showed a perovskite phase and dense microstructure. The BCeT thin films annealed at temperature as low as 550 °C become crystallized and exhibit a polycrystalline structure with ferroelectric properties. The 200-nm-thick BCeT thin films annealed at 700 °C showed a large remanent polarization (2Pr) of 62.1 μC/cm2 at an applied voltage of 10 V and exhibited a fatigue-free behavior up to 5×1010 switching cycles at a frequency of 100 kHz. These experimental results are thought to be promising to use cerium-substituted Bi4Ti3O12 thin films as capacitors of ferroelectric acces...

The effect of europium substitution on the ferroelectric properties of Bi 4 Ti 3 O 12 thin films has been investigated. Ferroelectric europium-substituted Bi 4 Ti 3 O 12 thin films were fabricated by spin-coating onto a Pt/Ti/SiO 2 /Si substrate. The structure and morphology of the films were analyzed using X-ray diffraction and scanning electron microscopy, respectively. After annealing at 750 °C, Bi 3.25 Eu 0.75 Ti 3 O 12 (BET) films become crystallized and exhibit a polycrystalline structure. The BET thin films showed a large remanent polarization (2 P r ) of 60.99 μC/cm 2 at an applied voltage of 10 V. The BET thin films exhibited no significant degradation of switching charge for at least up to 5×10 9 switching cycles at a frequency of 50 kHz.

The Bi 3.25 La 0.75 Ti 3 O 12 (BLT) thin films were prepared by metalorganic decomposition method. The effect of grain size on the ferroelectric properties during crystallization were investigated by x-ray diffraction and field emission scanning electron microscope. The grain size and the roughness of BLT films increase with increasing of drying temperature. The leakage current densities of the BLT thin film with large grains are higher than that with small grains. The remanent polarization of BLT increase with increasing grain size. As compared BLT with small grain size, the BLT film with larger grain size shows better fatigue properties. This may be explained that small grained films shows more degradation of switching charge than large grained films.

With the invention of the inlaying technique for celadon in the latter half of the 12th century, the Koryo potters reached a new height of artistic and scientific achievement in ceramics chemical technology. Inlaid celadon shards, collected in 1991 during the surface investigation of Kangjin kilns found on the southwestern shore of South Korea, were imbedded in epoxy resin and polished for cross-section examination. Backscattered electron images were taken with an electron microprobe equipped with an energy dispersive spectrometer. The spectrometer was also used to determine the composition of micro-areas. Porcelain stone, weathered rock of quartz, mica, and feldspar composition were found to be the raw material for the body and important components in the glaze and white inlay. The close similarity between glaze and black inlay in the microstructure suggests that the glaze material was modified by adding clay with high iron content, such as biotite, for use as black inlay. The deep soft translucent quality of celadon glaze is brought about by its microstructure of bubbles, remnant and devitrified minerals, and the schlieren effect.

The crystal structure and the dielectric properties of the antiferroelectric solid solution of (1 m x )Pb(Yb 1/2 Nb 1/2 )O 3 m x Ba(Yb 1/2 Nb 1/2 )O 3 (Pb 1 m x Ba x YN) (0 h x h 0.30) have been studied. The crystal structure is shown to become pseudocubic from the PYN's orthorhombic structure on solutionizing for x >0.5 while the transition shows a normal first-order paraelectric(PE) - antiferroelectric(AFE) behavior increasing x < 0.14. The transition temperature gradually decreases with the increasing Ba 2+ concentration. In the composition range 0.16 ¯ x ¯ 0.30, a typical relaxor behavior is displayed.

Cu2SnSe3 nanoparticles are sonochemically synthesized under multibubble sonoluminescence conditions from mixtures of CuCl, SnCl2, and Se dissolved in a mixture of ethanolamine and ethylene glycol (ultrasound, 25 °C, 20 min, 78% yield).

Palladium acetate complexes have been incorporated into polycarbonate (PC) films as a dispersion medium using tetrahydrofuran (THF). The resulting light brown-coloured homogeneous films of 10–30 wt.% Pd metal complex concentration are found to be thermally stable up to 150°C, and the relatively electron rich oxygen atoms of ketone groups in polycarbonate molecules are assumed to interact with Pd complexes on the basis of their infrared spectroscopic and thermal analyses. The reaction chemistry of Pd in PC has been investigated by reacting Pd sites with small gaseous molecules such as CO, H 2 , O 2 , NO, and olefins in the temperature range of 25 to 150°C, and various Pd-carbonyls, -hydride, -nitrosyl, and -ethylene species formed in PC are characterized. The treatment of Pd-containing PC film with H 2 gas at 120°C produces small Pd metal particles of ca. 40–330 A in diameter in PC, which show various catalytic reactivities in CO oxidation, NO reduction, dimethyl carbonate formation and hydrogenation of styrene-monomer.

RhCl[P(C 6 H 5 ) 3 ] 3 complexes have been incorporated in polycarbonate (PC) as a dispersion medium using cosolvent (THF). The interactions between Rh(I) complexes and polycarbonate polymer molecules are studied by infrared spectroscopy and thermal analysis. The reaction chemistry of Rh in PC films has been investigated by reacting Rh sites in PC with small gaseous molecules like CO, H 2 , D 2 , O 2 , NO, C 2 H 2 , and C 2 H 4 in the temperature range 25∼150°C. Various Rh–carbonyls, –hydride, –nitrosyl, and –superoxo dioxygen species formed in PC films are characterized by infrared spectroscopy. The Rh complexes in PC are easily reduced by reacting them with H 2 gas and such reduction results in the formation of small Rh metal particles of 20∼30 A in diameter in PC. The Rh complexes in PC show interesting catalytic reactivities such as hydrogenation of olefin and acetylene, oxidation of CO, reduction of NO, methanol synthesis from CO or CO 2, and oxidation of alcohol under relatively mild conditions.

Preparations of PbS-coated titanium dioxide (TiO 2 ) and lead sulfide (PbS) nanoparticles under ultrasonic field at the multibubble sonoluminescence (MBSL) conditions were tested in water solutions. Under the optimal MBSL conditions (20 kHz and 220 W power input), PbS nanoparticles (diameter = 40–50 nm) were prepared by treating lead nitrate and thioacetamide for 20 min in water solutions. The size of PbS nanoparticles was found to be easily increased to about 90 nm in diameter by increasing the reactant concentration twice. A similar sonochemical reaction with TiO 2 nanoparticles (about 20–30 nm in diameter) gave rise to PbS-coated TiO 2 nanoparticles with a core/shell structure. The PbS thin film coating was quite uniform and the average coating depth of PbS on the TiO 2 nanoparticles was about 2–3 nm under the described conditions. It is interesting to note that the coating depth was found to be controlled to 2–10 nm range by increasing the amounts of reactants for Pb and S twice with a sonication time of 30 min.

A new pseudo-two-dimensional compound, BaGa(2)O(2)(OH)(4), containing pure inorganic helical chains has been synthesized under hydrothermal reaction conditions using Ba(OH)(2).8H(2)O, Ga(2)O(3), and H(2)O as reagents. Further characterizations as well as a reversible transformation reaction to BaGa(2)O(4) and H(2)O are discussed.

Dielectric, P-E hysteresis loop, and X-ray diffraction measurements of the (Pb1-x Srx)(Mg1/2 W1/2)O3 ceramics system have been conducted in order to study the effect of A-site atomic substitution on phase transition. It is found that an antiferroelectric intermediate phase begins to appear with the addition of Sr. The temperature range of the intermediate phase increases with the Sr concentration. The transition temperature of the intermediate phase region from the paraelectric state is shown to be nearly independent of Sr content. However, the transition temperature into a low temperature antiferroelectric state from an intermediate phase region is found to be strongly dependent on the concentration of Sr. The transition behavior of the system is related to two modulations based on X-ray diffraction analyses

C, the ZnSe film as a window layer can be successfullydeposited on the CIGS substrate with a longer depositiontime without damaging the CIGS layer.According to EDX data, the composition of the filmscorresponds to the 1 : 1 stoichiometry between Zn and Se inthis temperature range and there are no appreciable amountsof impurities such as carbide or oxide. UV-Vis spectroscopyfor these films indicates that the band gap of ZnSe films forboth precursors ranges from 2.65 eV to 2.8 eV, dependingupon the deposition process. Thus, it is believed that theZnSe films prepared in this study is very likely to replaceCdS (band gap: 2.44 eV), which is quite harmful to theenvironment.In conclusion, two new single-source precursors for ZnSethin film were synthesized and characterized. Both precur-sors were found to have improved thermal properties ofrelatively very low melting and decomposition temperatures,which are quite suitable in their application to a windowlayer material through MOCVD method. Using these pre-cursors, ZnSe thin films were successfully deposited onvarious substrates with a relatively large growth rate.

Numerous physical properties of CdS films notablydepend on their deposition methods and the particularconditions of preparation processes. They can be preparedby chemical, physical and electrochemical methods such asmolecular beam epitaxy (MBE); metal organic chemicalvapor deposition (MOCVD); close-spaced sublimation (CSS);chemical bath deposition (CBD); electro-deposition; succe-ssive ionic layer adsorption and reaction (SILAR); screenprinting; pulsed laser ablation; RF sputtering; and spraypyrolysis.

In2Se3 is a binary compound, which is attracting wide attention because it can be used as an important material for polycrystalline thin film solar cell. It has various structural modifications of α, β, and γ-phase, and they have quite different electronic properties; α-phase of In2Se3 has low band gap, 1.2-1.3 eV at the temperature below 200 C. As temperature goes up to above 200 C, it is transformed to βphase with a band gap of 1.4 eV. In addition, when temperature goes to higher temperature, 350 C, it is converted to γIn2Se3 with a band gap of 1.8 eV. Particularly, γ-In2Se3 is interesting since it can be adopted as a suitable absorber layer in CdS/In2Se3 or In2S3/In2Se3 photovoltaic cells because of its high absorption coefficient and the band gap which is in an optimum range for solar energy conversion. Moreover, it can be used as a starting material to obtain CuInSe2 or Cu(InGa)Se2 thin films. The In2Se3 thin films can be prepared through various methods such as thermal evaporation, spray pyrolysis, metal organic chemical vapor deposition (MOCVD), electrochemical atomic layer epitaxy, electrodeposition, and many other methods. Among them, MOCVD method has many practical benefits than any other methods; especially, the composition, structure, and morphology of the In2Se3 thin films can be properly controlled. Furthermore, its process is rather simple and less expensive if a suitable single source precursor is available. In this research, two single source precursors, containing indium and selenium atoms: tris(N,N-ethylbutyldiselenocarbamato)indium(III) and tris(2-ethylpiperidinediselenocarbamato)indium(III), designated as In(ebdsc)3 and In(epdsc)3, respectively, were synthesized with high purity, and using them, γ-In2Se3 thin films were prepared by MOCVD.

20 wt% RuCl 3 ·3H 2 O-containing polycarbonate membranes are prepared by using co-solvent and using these metal-containing membranes, over 99% of pure oxygen (O 2 ) gas was recovered from a 1 : 1 mixture of O 2 and CO gas mixture at room temperature. Under the described conditions, the Ru complexes are inert to oxygen, but quite reactive to carbon monoxide gas molecules. Very stable Ru-carbonyl species are found to be formed during the gas permeation in the membrane, indicating that there are relatively strong interaction between CO gas molecules and the Ru complexes incorporated into the polycarbonate membrane. Such preferential interactions are believed to give rise to a drastic change in permeation selectivity of a organic polymer membrane.

Em- ail: iwshim@cau.ac.krRecevied June 3, 2005Key Words : ZnS, Zinc sulfide thin film Zi, nc dithoi carbamate, MOCVD, Buffer layer in soalr cellZnS, a group II-VI semiconductor having a large directband gap of 3.6 eV in near UV region and a refractive indexof 2.35, is well known to be an important device material,which can be used for detector, emitter, and modulator inoptoelectronics

RuCl3·3H2O complexes have been incorporated into polycarbonate using solvent. The interactions between Ru complexes and polycarbonate (PC) are examined by infrared spectroscopy and thermal analysis. The reaction chemistries of these Ru-containing films have been investigated by reacting the Ru sites with CO, O2, H2, D2, NO, and C2H4. They show interesting catalytic activities in various gas phase reactions under relatively mild conditions such as NO reduction, hydrogenation of ethylene and benzene, water-gas shift reaction, and oxidation of n-butyl sulfide.

Recently, the preparation of silver metal thin films through chemical vapor deposition (CVD) has been a research field of particular interest due mainly to their wide variety of applications, such as contact materials in microelectronic circuitry, 1 components of high Tc superconductors, 2 bactericidal coatings, 3 and the development of electroluminescent materials. 4 A central issue in the typical low-pressure CVD process for the preparation of silver films has been the development of thermally stable silver precursors; a number of Ag precursors has been reported but they often showed low volatility and thermal and/or photochemical instability. Among them, silver β-diketonate phosphine adducts were interesting since phosphine ligands could function as both anti-oligomerization and deoxygenating agents. The incorporation of the ancillary ligands is believed to give rise to coordination saturation around silver metal and to prevent oligomerization reaction. Also, the phosphine ligands are well known to reduce oxygen contamination in silver films. But many of the phosphine compounds are pyrophoric or air sensitive. Accordingly, in this study, various phosphites were chosen as an ancillary ligand because they are relatively more stable and easy to handle. Besides, such phosphite ligands are expected to be better π acceptors than phosphine ligands, leading to more thermally stable silver complexes. Also, silver selenide thin films have been extensively studied because of their potential applications to superionic conductors, 5 solar cells, 6 thermochromic materials, and photosensitizers. 7 In this background, new phosphite adduct precursors of silver β-diketonate complexes were synthesized and characterized by various spectroscopic methods. Using them, silver metal films were deposited on glass or silicon substrates through MOCVD method. Then, those silver metal films were converted to Ag2Se film by selenium vapor deposition. Experimental Section

Department of Chemistry, Chung Ang University, Seoul 156-756, KoreaReceived October 2, 2002Key Words : Copper thin film by MOCVD, Copper selenide thin film by selenium vapor depositionRecently, the preparation of copper selenide thin film hasattracted much attention of particular interest due to theirwide applications such as electronic and electro-opticaldevices.

Palladium (Pd) acetate complexes have been incorporated in polysulfone (PS) as a dispersion medium using cosolvent (tetrahydrofuran). The resulting brown-colored [PS-Pd] films of 10–40 wt% complex concentration are thermally stable up to 140°C. Upon incorporation of Pd metal into PS, the glass transition temperatures of the films increase as Pd metal concentration increases. The acetate ligands in [PS-Pd] films are found to be substituted by Cl−1 or CN−1 ligands in aqueous solution. As a result of the relatively easy reduction of Pd(II) in PS to Pd(0), palladium metal particles in various sizes are observed to be formed in PS. The Pd complexes in PS show catalytic activities in hydrogenation of ethylene, CO oxidation and NO reduction by CO or H2 gases under relatively mild conditions.

RuCl 3 · 3H 2 O complexes are incorporated into polysulfone (PS) as a dispersion medium using a cosolvent (tetrahydrofuran) in the metal complex concentration range of 5–30 wt.%. The interactions between Ru(III) complexes and PS are examined by infrared spectroscopy and thermal analyses (differential scanning calorimetry, DSC). The chemical reactivities of Ru in PS are investigated by reacting Ru sites with CO, H 2 , O 2 , NO, D 2 , N 2 , and C 2 H 4 gases in the static state under relatively mild conditions. Various Ru carbonyl, nitrosyl and hydride species formed in PS are characterized by infrared spectroscopic analyses and isotopic methods. Partial reduction of Ru(III) to Ru(II) is observed in reactions of the Ru-containing PS films with CO-H 2 O or H 2 . These films show catalytic activities in the hydrogenation of ethylene, a water-gas shift reaction and reduction of NO under relatively mild conditions.

RuCl3·3H2O complexes have been incorporated in cellulose acetate (CA) as a dispersion medium using a cosolvent (tetrahydrofuran). The interactions between Ru(III) complexes and CA were examined by infrared spectroscopy and thermal analysis (DSC). The reaction chemistry of 10 wt.% ruthenium-containing CA films was investigated by reacting Ru sites with CO, H2, O2 and H2O under mild conditions. Four different Ru-carbonyls formed in CA were characterized; among them, physically adsorbed CO molecules on Ru sites in CA were found to be relatively reactive. Treatment of the Ru-containing CA films with hydrogen (600 torr) at 130 °C produced quite stable ruthenium hydride species, which was confirmed by identifying the corresponding ruthenium deuteride. Partial reduction of RU(III) to RU(II) was observed in reactions of the films with CO/H2O or H2. The Ru-containing CA films show catalytic activities in oxidation of CO to CO2 and the water-gas shift reaction under relatively mild conditions.

Two new metal antimony oxychlorides, Sb(2)ZnO(3)Cl(2) and Sb(16)Cd(8)O(25)Cl(14), have been synthesized by solid-state reactions using Sb(2)O(3) and ZnCl(2) (or CdCl(2)) as reagents. The structures of Sb(2)ZnO(3)Cl(2) and Sb(16)Cd(8)O(25)Cl(14) have been determined by single-crystal X-ray diffraction. Both of the reported materials contain Sb(3+) cations that are in an asymmetric coordination environment attributable to their stereoactive lone pair. Sb(2)ZnO(3)Cl(2) has a novel two-dimensional layered structure consisting of distorted ZnO(2)Cl(2) tetrahedra and SbO(3) polyhedra. Sb(16)Cd(8)O(25)Cl(14) exhibits a one-dimensional structure consisting of Sb(3+)-Cd(2+)-oxide rods, Cd(2+)-chloride double chains, and isolated Cl(-) ions. Complete separation of the halophile and chalcophile moieties is observed from the reported materials. Detailed structural analysis, IR spectra, thermogravimetric analysis, ion-exchange reactions, and dipole moment calculations are presented. Crystal data: Sb(2)ZnO(3)Cl(2), orthorhombic, space group Pnma (No. 62), a = 17.124(4) A, b = 5.5598(12) A, c = 6.4823(14) A, V = 617.2(2) A(3), and Z = 4; Sb(16)Cd(8)O(25)Cl(14), monoclinic, space group I2/m (No. 12), a = 14.251(3) A, b = 3.9895(8) A, c = 21.145(4) A, beta = 97.35(3) degrees, V = 1192.3(4) A(3), and Z = 8.

RhCl [P(C6H5)3]3 complexes have been incorporated in cellulose acetate as a dispersion medium using cosolvent (tetrahydrofuran). The interactions between Rh (I) complexes and cellulose acetate (CA) are examined by infrared spectroscopy and thermal analysis. The chemical reactivities of Rh–CA films have been investigated by reacting Rh sites with CO, H2, O2, and C2H4 in the temperature range 90–150°C and at a pressure of less than 1 atm. Three different Rh-carbonyls and a Rh-hydride species formed in CA are characterized by their infrared spectra. Treatment of 10 or 20 wt % Rh–CA films with hydrogen (600 torr) at 150°C produces small Rh metal particles of ca. 10 A or less in diameter in CA, which show catalytic activities under mild conditions in various reactions such as hydrogenation of C2H4, oxidation of CO, and Fischer–Tropsch type reactions.

In recent years, a large number of nano-size semiconductors have been investigated for their potential applications in photovoltaic cells, optical sensor devices, and photocatalysts [1, 2, 3]. Nano-size semiconductor particles have many interesting properties due mainly to their size-dependent electronic and optical properties. Appropriately, many speciality of nanomaterials such as CdS and ZnS semiconductor particles, and other metal oxides such as ZnO and lithium-titanate oxide (LTO) have been prepared. However, most of them were prepared with toxic reactants and/or complex multistep reaction processes. Particularly, it is quite difficult to produce LTO nanoparticles, since it typically requires wearisome conditions such as very high temperature over 1000 °C, long producing times, and so on. To overcome such problems, various core/shell type nanocrystals were prepared through different methods such as the hydrothermal synthetic method, microwave, and sonochemistry. Also many coating methods on inorganic oxide nanoparticles were tried for the preparations of various core-shell type nanocrystals. Sonoluminescence (SL) is a light emission phenomenon associated with the catastrophic collapse of a gas bubble oscillating under an ultrasonic field [4]. Light emission of single bubble sonoluminescence (SBSL) is characterized by picosecond flashes of the broad band spectrum extending to the ultraviolet [5, 6]. The bubble wall acceleration has been found to exceed 1011 g at the moment of bubble collapse. Recently observed results of the peak temperature and pressure from the sonoluminescing gas bubble in sulfuric acid solutions [9] were accurately predicted by the hydrodynamic theory for sonoluminescence phenomena [7, 10, 11, 12], which provides a clue for understanding sonochemical reactions inside the bubble and liquid layer adjacent to the bubble wall. Sonochemistry involves an application of sonoluminescence. The intense local heating and high pressure inside the bubbles and liquid adjacent bubble wall from such collapse can give rise to unusual effects in chemical reactions. The estimated temperature and pressure in the liquid zone around the collapsing bubble with equilibrium radius 5 μm, an average radius of bubbles generated in a sonochemical reactor at a driving frequency of 20 kHz with an input power of 179 W, is about 1000 °C and 500 atm, respectively. At the proper condition, a lot of transient bubbles are generated and collapse synchronistically to emit blue light when high power ultrasound is applied to liquid, and it is called multibubble sonoluminescence (MBSL). Figure 1 shows an experimental apparatus for MBSL with a cylindrical quartz cell, into which a 5 mm diameter titanium horn (Misonix XL2020, USA) is inserted [13]. The MBSL facilitates the transient supercritical state [14].in the liquid layer where rapid chemical reactions can take place. In fact, methylene blue (MB), which is one of a number of typical textile dyestuffs, was degraded very fast at the MBSL condition while MB does not degrade under simple ultrasonic irradiation [13]. MBSL has been proven to be a useful technique to make novel materials with unusual properties. In our study, various metal oxides such as ZnO powder [15], used as a primary reinforcing filler for elastomer, homogeneous Li4 Ti5 O12 nanoparticles [16], used for electrode materials, and core/shell nanoparticles such as CdS coating on TiO2 nanoparticles [17] and ZnS coating on TiO2 nanoparticles [18], which are very likely to be useful for the development of inorganic dye-sensitized solar cells, were synthesized through a one pot reaction under the MBSL condition. Figure 2 shows the XRD pattern of ZnO nanoparticles synthesized from zinc acetate dehydrate (Zn(CH3 CO2 )2 · 2H2 O, 99.999%, Aldrich) in various alcohol solutions with sodium hydroxide (NaOH, 99.99%, Aldrich) at the MBSL condition. The XRD patterns of all powers indicate hexagonal zincite. The XRD pattern for the ZnO nanoparticles synthesized is similar to the ZnO powder produced by a modified sol-gel process and subsequent heat treatment at about 600 °C [19] as shown in Fig.3. The average particle diameter of ZnO powder is about 7 nm. A simple sonochemical method for producing homogeneous LTO nanoparticles, as shown schematically in Fig. 4. First, LiOH and TiO2 nanoparticles were used to prepare LiOH-coated TiO2 nanoparticles as shown in Fig.5. Second, the resulting nanoparticles were thermally treated at 500 °C for 1 hour to prepare LTO nanoparticles. Figure 6 shows a high resolution transmission electron microscope image of LTO nanoparticles having an average grain size of 30–40 nm. All the nanoparticle synthesized are very pure in phase and quite homogeneous in their size and shape. Recently we succeeded in synthesizing a supported nickel catalyst such as Ni/Al2s O3 , MgO/Al2 O3 and LaAlO3 , which turned out to be effective for methane decomposition [20]. Sonochemistry may provide a new way to more rapidly synthesize many specialty nanoparticles with less waste [21]. This clean technology enables the preparation of new materials such as colloids, amorphous particles [22], and various alloys.Copyright © 2008 by ASME

Cu2ZnSnS4 (CZTS) nanoparticles were synthesized by sonochemical reactions under multibubble sonoluminescence (MBSL) conditions. First, Cu2SnS3 (CTS) nanoparticles were synthesized by the sonochemical method with a 91.3% yield. Second, ZnS was coated on Cu2SnS3 nanoparticles by the same method. Then, they were transformed into CZTS nanoparticles of 90-300 nm diameter by heating them at 450 °C for 1 hour. The ratios between Zn and Sn could be controlled from 0.20 to 1.32 by adjusting the relative concentrations of Cu2SnS3 and ZnCl2. With relatively lower Zn : Sn ratios (0.20-0.41), there was a mixture of CTS and CZTS nanoparticles. The prepared nanoparticles show different band gaps from 1.19 to 1.52 eV depending on the zinc to tin ratio. In this sonochemical method without using any toxic or high temperature solvents, the specific stoichiometric element ratios in CZTS were controllable on demand and their experimental results were always reproducible in separate syntheses. The CZTS nanoparticles were investigated by using X-ray diffraction, a UV-Vis spectrophotometer, a scanning electron microscope, Raman spectroscopy, and a high resolution-transmission electron microscope.