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The performance deterioration of RO membrane processes caused by the accumulation of rejected solutes on membrane surface is an inevitable phenomenon in membrane processes. The feed spacer in spiral wound reverse osmosis (RO) membrane modules can provide the structural support to keep feed channel open and also allow turbulent flow to mitigate solute concentration build-up at the vicinity of membrane surface. The objective of this study was to investigate the effect of feed spacer thickness on both membrane fouling behavior and cleaning efficiency in a pilot test during a 659 h operation. Furthermore, fouling load distribution was studied by measuring normalized differential pressure of individual elements in pressure vessels. Foulant analysis according to feed spacer thickness was also conducted to compare fouling propensities. This study showed that a thicker feed spacer could reduce membrane fouling and subsequently decrease membrane cleaning frequency and allow an even fouling load distribution along the modules installed in a pressure vessel.

The effects of the Pt catalyst sputter deposited on the patterned ITO glass (SD-Pt/pITO) on the photovoltaic properties and charge-transfer characteristics at the Pt/electrolyte interface of dye-sensitized solar cells (DSSCs) are studied and compared with those of a conventional Pt counter electrode deposited by thermal reduction on fluorine-doped tin oxide (FTO) glass (TD-Pt/FTO). The DSSC with the SD-Pt/pITO (sample cell) shows a lower charge-transfer resistance than that of the DSSC with the TD-Pt/FTO (reference cell), which leads to an improvement of its fill factor by about 7.6%. The long-term durability test performed for 1000 h at room temperature reveals that the sample cell retains up to 99% of its energy conversion efficiency, while that of the reference cell is degraded by about 7.2%.

The fabrication process of semiconductor is more and more difficult as scaling down. Especially, the via profile formation is one of the main challenges which is suffering from making stable device process because ArF photo resist (PR) itself can not provide proper etch selectivity to sub-layers. Recently, many researches have been studied for the via process in terms of photo property, etch property and process compatibility using bi-layer resist process (BLR), tri-layer resist process (TLR), and multi-layer resist (MLR) process. In this paper, we proposed and demonstrated for beyond 90nm scaled logic via process consisting of high-k inter metal dielectric (IMD) using multi-layer resist (MLR) organic hard mask. Based on the test results described in this paper, the results show the higher etching selectivity to each layer and also helped to easily control the anisotropic profiles.

We studied the durability of the previously reported low mass loaded, highly efficient electrospray deposited Pt film as a cathode and Ni mesh as anode electrode in PV assisted water electrolysis system for 1000 h. This assembly showed no detectable decline in performance for initial 200 h, but thereafter it started to decline with time and showed 18% decline after 1000 h. For conclusion, we analyzed the electrode surfaces by different analyzing techniques. Results showed that Pt film was detaching from the surface and there was a deposition of passive layer of Fe2O3 on edge side of cathode surface. The iron derivative might be come from the corrosion of the stainless steel connectors that we used in PV assisted water electrolysis system. The etching and oxidation of anode surface was also observed but it might not be responsible for deterioration of performance.

A gel electrolyte based on polyurethane as a polymer matrix was prepared by the UV curing of a liquid electrolyte containing an aliphatic urethane acrylate. By controlling the concentration of the polymer matrix, the ionic conductivities of the gel electrolytes were varied from 9.8 × 10−3 S/cm to 4.7 × 10−3 S/cm at room temperature. The quasi-solid state dye-sensitized solar cell (DSSC) fabricated with the gel electrolyte rendered an overall energy conversion efficiency of 6.1% under irradiation of 100 mW/cm2 at room temperature. The DSSC employing the gel electrolyte showed better photovoltaic performance than the DSSC assembled without the polyurethane at temperatures above 55 °C.

The effect of the addition of single and binary additives to a mixed solvent, ethylene carbonate + γ-butyrolactone, on the performance of dye-sensitized TiO 2 solar cells (DSSCs) has been investigated. The addition of a single additive, 2-(dimethylamino)-pyridine, to the electrolyte containing an ionic salt, 1,2-dimethyl-3-propylimidazolium iodide, in the mixed solvent results in an enhancement of the cell performance. The performance of the cell has been further enhanced by the addition of the second additive, 5-chloro-1-ethyl-2-methylimidazole. The resulting DSSC has performed better than the one based on the conventional electrolyte in acetonitrile. The dependence of the stability of the cells on the temperature has been evaluated over the range of 30–120 °C for outdoor applications.

A novel alkylimidazolium iodide containing an amide group, 1-(2-hexanamidoethyl)-3-methylimidazol-3-ium iodide (amido-ImI), was synthesized to act as the quasi-solid-state electrolyte of dye-sensitized solar cells (DSSCs). The DSSC with the amido-ImI electrolyte exhibited short-circuit photocurrent density ( J sc ) and overall energy conversion efficiency ( η ) that were improved by 7.2% and 10.2%, respectively, compared to those obtained with the cell containing 1-hexyl-2,3-dimethylimidazolium iodide, a commonly used liquid electrolyte, at 100 mW cm −2 . Furthermore, the stability of the DSSC was enhanced by the presence of amido-ImI.

The initial decrease in the short-circuit photocurrent density (Jsc) of a Ru(II)–bipyridine dye-sensitized solar cell (DSSC) during illumination is correlated with the decrease in the amount of remaining dye adsorbed on the TiO2 film monitored by UV–vis absorption spectroscopy. The analyses reveal that the illumination causes the N719 dye molecules to desorb from the TiO2 film into the electrolytic solution. The amount of dye remaining adsorbed on the TiO2 film is influenced by the viscosity and donor number of the electrolytic solution. More dye molecules remain adsorbed on the TiO2 film in the solution of 3-methoxypropionitrile than in the less viscous solution of acetonitrile. The addition of water and Triton X-100 to the 3-methoxypropionitrile solution results in the enhancement of the dye desorption, partly due to the increase in the donor number.

Blocking layers are formed on the conductive fluorine-doped tin oxide (FTO) substrate by using titanium (IV) bis(ethylacetoacetato) diisopropoxide precursor solutions with different concentration to investigate the effect of the precursor concentration on thickness and morphology of blocking layers and photovoltaic property in dye-sensitized solar cell. Increase in the precursor concentration from 0.05 M to 1.2 M leads to increase in the blocking layer thickness from 10 nm to 240 nm. Besides increase in the thickness, nanoparticulate intralayer morphology is developed as increasing the precursor concentration. Photovoltaic property, especially photocurrent density (JSC), is influenced by the precursor concentration, where JSC increases with increasing the concentration, reaches maximum at around 0.1 M (blocking layer thickness is about 20 nm), decreases gradually up to 0.4 M and become close to the value without blocking layer for further increase in the concentration. Photovoltages increase slightly after formation of blocking layer, but not significantly altered compared with the extent of photocurrent change. It has been found that the precursor concentration with around 0.1 M provides the optimum condition to protect the loss of electrons within our experimental condition and at this condition the photoconversion efficiency is able to be enhanced by about 6% compared with that without blocking layer. Electrochemical impedance spectroscopic study shows that the dependence of photovoltaic property on Ti precursor concentration is closely related to the charge transfer resistance at the blocking layer/electrolyte interface, where the electron loss at near FTO substrate is effectively protected by the blocking layer with the maximum charge transfer resistance.

A highly viscous liquid electrolyte is prepared by adding a small amount of amylopectin into dimethylsulfoxide solvent. By using this viscous electrolyte, a dye-sensitized solar cell (DSSC) enhances the short-circuit photocurrent density and solar-to-electricity conversion efficiency by 22% and 8.4%, respectively, compared to those obtained with the reference cell without amylopectin. Furthermore, the stability of the DSSC is enormously improved by the addition of amylopectin. Polarization curves indicate that amylopectin is a reasonable corrosion inhibitor for silver metal in the electrolyte containing I 3 − /I − couple.

The performance of a Ru(II) dye-sensitized nanocrystalline TiO 2 solar cell (DSSC) with both Triton X-100 and water as additives in 3-methoxypropionitrile solutions is described. In the presence of these additives, the open-circuit voltage ( V oc ), fill factor and stability of the cell increased, while the short-circuit photocurrent density decreased compared to those found in their absence. Based on these changes, the DSSC yielded a higher solar-to-electricity conversion efficiency of 5.9%, compared to 5.3% for the cells fabricated without the additives. Furthermore, the addition of Triton X-100 to the water-added electrolyte was found to render the Ag metal corrosion resistant.

A novel ionic electrolyte, 3-(iodohexyl)-1-(3-(triethoxysilyl)propylcarbamoyl)-1H-benzo[d]imidazol-3-ium iodide (SSBI) was prepared through the reaction of N-[3-(triethoxy-4-silyl)propyl]-1H-benzimidazole-1-carboxamide with 1,6-diiodohexane for the quasi-solidification of the electrolytic solution of a dye-sensitized solar cell (DSSC). The SSB-containing electrolyte, the sol electrolyte, in a DSSC was converted to a gel by heating it at 60 °C for 30 min in an oven. The DSSC consisting of the gel electrolyte showed a solar-to-electricity conversion efficiency comparable to that of the cell with the reference liquid electrolyte, and consistently higher stability than that of the reference cell. The performances of the DSSCs containing the reference, sol and gel electrolytes were discussed by scanning electron microscopy (SEM), impedance and chronoamperometric measurements, ionic conductivity, and UV–vis absorption spectroscopy.

Plasma-polymerized fluorine-containing thin films were fabricated by five different plasma methods, viz. inductively coupled plasma (ICP), pulsed-plasma (PP), capacitively coupled plasma (CCP), self-ignition plasma (SIP), and plasma source ion implantation/inductively coupled plasma (PSII/ICP). Octafluoropropane (C3F8) was mixed with acetylene (C2H2) to investigate the effect of different plasma techniques on the films. The properties of the plasma polymers, viz. hydrophobic properties, binding structure, deposition rate, and chemical composition, varied considerably depending on the plasma polymerization method. The plasma-polymerized thin films made by the different methods were characterized using surface analytical instruments: field-emission scanning electron microscope (FE-SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS), and time-of-flight secondary ion mass spectrometry (TOF-SIMS). Cross-section images from FE-SEM revealed that the deposition rate of the polymer film in the case of using CCP plasma was higher while that for PSII/ICP and self-ignition plasma, respectively, was lower compared with the deposition rate of the ICP and pulsed-plasma. The water contact angle measurement showed that the ICP and PSII/ICP techniques produced more hydrophobic surfaces. XPS and TOF-SIMS analyses indicated that the ICP and PSII/ICP methods produced more F-containing functional groups, especially CF2 and CF3 groups. Also, the NEXAFS results revealed that the ICP and PSII/ICP techniques provide more fluorine species on the plasma polymer surface compared with other techniques.

The identification of the colorants used on ancient textiles provides a historical pathway to the understanding of the processes associated with one of the oldest of chemical technologies, namely textile dyeing. In this paper, time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to detect dyes on textiles avoiding the time-consuming and destructive extraction procedures necessary for the spectrophotometric and chromatographic methods previously used. The plant dyes investigated belong to a variety of chemical groups, which include curcumin, crocin, carthamin, purpurin, alizarin, brazilin, shikonin, and indigo. Reference textile samples were prepared with dye extracts of plants and were characterized by TOF-SIMS. TOF-SIMS spectra for the dyed textiles showed element ions from metallic mordants, specific fragment ions, and molecular ions from organic dyes. Remnant dyes on excavated textiles have also been identified using TOF-SIMS. The ancient textile sample showed the presence of indigo clearly, although the fiber itself had degraded badly. From the results, it was concluded that most of plant dyes can be identified with TOF-SIMS and it is a very promising technique for the archaeology field.

Spherical rutile TiO 2 particles (14–20 nm) and their corresponding well-defined round clusters (500–600 nm) were obtained by using a cationic surfactant cetyltrimethylammonium bromide (CTAB). The surfactant was employed in two stages, i.e., in the hydrolysis of TiCl 4 and then in the precipitation of the corresponding Ti(IV) polymers at approximately 46 °C. On the other hand, without CTAB in the hydrolyzing solution, irregular clusters consisting of typical ellipsoidal TiO 2 particles were produced. The advantage of such spherical rutile TiO 2 particles and clusters was examined in terms of photovoltaic characteristics of a dye-sensitized solar cell (DSSC). Significantly higher overall solar energy conversion efficiency was obtained for a DSSC using the film of these spherical rutile TiO 2 particles, compared with that of a cell using a TiO 2 film of ellipsoidal particles. A mechanism for the formation of these spherical rutile particles and clusters is proposed.

Platycosides extracted from Platycodi Radix were analyzed by HPLC coupled with electrospray ionization multistage tandem mass spectrometry (HPLC/ESI-MS(n)). Predominant [M+Na](+) ions in positive mode and [M-H](-) ions in negative mode in the direct ESI-MS spectra of extract provided information on molecular weights, but minor components and isomers could not be discriminated. However, combining HPLC and ESI-MS(n), allowed eleven platycosides, including four acetylated platycodin isomers and two prosapogenines to be analyzed. During MS(2) analysis conducted to elucidate the structures of platycosides, fragment ions provided information on sugar moieties attached at C-28 of triterpene structure of the platycosides. Glycosidic bond cleavages at C-3 were revealed by fragment ions in MS(3) spectra. Some characteristic fragment ions not related to sugar bond cleavage revealed that an esterified triterpene is linked to sugars at C-28. The only sugar ring-cross cleavage corresponding to 90 Da in the negative MS(2) spectrum took place at an arabinosyl sugar moiety. By using HPLC/ESI-MS(n), three acetylated platycosides in Platycodi Radix extract were newly identified.

A counter electrode was prepared for a dye-sensitized solar cell (DSSC) through electrochemical deposition of mesoporous platinum on fluorine-doped tin oxide glass in the presence of a structure-directing nonionic surfactant, octaethylene glycol monohexadecyl ether (C 16 EO 8 ). The DSSC fabricated with the electrochemically deposited Pt (ED-Pt) counter electrode rendered a higher solar-to-electricity conversion efficiency of 7.6%, compared with approximately 6.4% of the cells fabricated with the sputter-deposited or most commonly-employed thermal deposited Pt counter electrodes. This enhanced efficiency is attributed to the higher short-circuit photocurrent arising from the increases in the active surface area and light reflection as well as the decrease in the sheet resistance of the ED-Pt film, relative to those of the Pt films prepared by the other two deposition methods. The sputter-deposited Pt film yielded almost the same photovoltaic characteristics as the thermal deposited Pt film. The Pt films were characterized by FE-SEM, AFM, cyclic voltammetry, chronoamperometry, electrochemical impedance spectroscopy, sheet resistance measurements, adhesion tests, and light reflection tests.

The effects of low-temperature O2 plasma treatment of a TiO2 film are studied with the objective of improving the performance of dye-sensitized solar cells (DSSCs). X-ray photoelectron spectra (XPS) reveal that the ratio of titanium dioxide to titanium sub-oxides is increased in the O2 plasma-treated TiO2 film, compared with that of the untreated TiO2 film. This increase suggests that the oxygen vacancies in the film are effectively reduced. The near-edge X-ray absorption fine structure (NEXAFS) spectra results agree with the XPS result. It is proposed that there is a correlation between the shifts of the peaks in the NEXAFS spectra and the adsorption of N719 dye on the TiO2 particles. A DSSC having an O2 plasma-treated, 4 μm thick TiO2 film electrode renders a short-circuit photocurrent of 7.59 mA cm−2, compared with 6.53 mA cm−2 for a reference cell with an untreated TiO2 electrode of the same thickness. As a result of these changes, the solar-to-electricity conversion efficiency of the O2 plasma-treated cell is found to be 4.0% as compared with 3.5% for the untreated cell. This improvement in the performance is rationalized on the basis of increased N719 dye adsorption on to the TiO2, due to the reduction in the number of oxygen vacancies caused by the oxygen plasma treatment.

Network hybrid gel prepared with tetraethyl orthosilicate, 3-aminopropyltrimethoxysilane (APS) and poly(ethylene glycol) was used as an electrolyte matrix in a quasi-solid state dye-sensitized solar cell (DSSC). Change in pH of this hybrid gel by varying the composition of APS was found to have remarkable effects on the photoelectrochemical performance of the cell. The hybrid gel matrix, having silane polymer backbones with free amine functionality, was characterized by FT-IR spectra and FE-SEM images, and the assembled DSSC by photocurrent-voltage and incident photon to current conversion efficiency curves. The unsealed, quasi-solid state DSSC with the hybrid gel has shown an increase in the open-circuit voltage ( V oc ) and a steady decrease in the short-circuit photocurrent ( J sc ), with increase in the content of APS. A maximum conversion efficiency of 4.5% was obtained for a DSSC by using 20% of APS in its hybrid gel at a light intensity of 100 mW cm −2 . Upon replacing the amino group of APS by bulkier aniline and benzophenoaniline groups, conversion efficiencies of the corresponding DSSCs were reduced. Variations in the V oc and J sc are explained in terms of shift of the flat band potential of TiO 2 and a complex formation between I 3 − and −NH 2 of APS of the electrolyte.

Summary A synthetic route was developed to link N3 dye to polyacrylic acid (PAA) using ethylenediamine (en) as the linker. The resulting complex, PAA–en–N3, was then coated onto a TiO2 film. The modified TiO2 film electrode (hereafter PAA–en–N3/TiO2), when used as the photoanode in a dye-sensitized solar cell (DSSC), exhibited enhanced solar energy conversion efficiency compared with that of the usual DSSC with the N3/TiO2 film electrode. The increase in efficiency was attributed to the increased open-circuit voltage (Voc) and short-circuit photocurrent (Jsc). The increase in Voc was attributed to the formation of a hydrophobic PAA–en–N3 layer on the TiO2/electrolyte interface, while the increase in Jsc was attributed to the additional dye acquired by the TiO2 film from the PAA–en–N3 complex.

The microscale pyrolysis of a mixture of 2,4,6-tribromophenol (2,4,6-TBP) and 2,4,6-trichlorophenol (2,4,6-TCP) was investigated. Several pyrolyzed products resulting from the gas phase reactions were analyzed by gas chromatography/mass spectrometry (GC/MS). Some products, including tetrabromo- and tetrachloro-dibenzo- p -dioxins, were identified by comparison of their retention times and mass spectra with those of products obtained from the pyrolysis of the corresponding 2,4,6-TBP and 2,4,6-TCP. 1,3,6,8- and 1,3,7,9-halogen substituted dioxin isomers were produced as major products via the condensation of phenoxyphenol radicals. The condensation of 2,4,6-TBP led to the more rapid production of tetrabromodibenzo- p -dioxins (TBDDs) than of tetrachlorodibenzo- p -dioxins (TCDDs) from 2,3,6-TCP due to the weaker C–Br than C–Cl bond strength. In the study of a mixture of 2,4,6-TCP and 2,4,6-TBP, the most abundant congeners were dibromo-dichlorodibenzo- p -dioxins. On the basis of the pyro-products analysis, the thermal decay of 2,4,6-TCP and 2,4,6-TBP, and the formation of halogenated dioxins as a function of the pyrolysis temperature were also investigated. The increased reactivity can be explained by the hypothesis that “dibromophenoxy radical are formed more easily by debromination of 2,4,6-TBP than that of 2,4,6-TCP, which rapidly reacts with 2,4,6-TCP and 2,4,6-TBP at low temperatures”. The formation distribution of tetra-bromochlorodibenzo- p -dioxins (tetra-BCDDs) indicated that more chlorinated dioxins were produced at low temperatures, but more brominated dioxins were formed at high temperatures.

In a novel approach, fullerene, C 60 was attached to N3 dye ( cis -bis(4,4′-dicarboxy-2,2′-bipyridine)dithiocyanato ruthenium(II)) via diaminohydrocarbon linkers (L) with different carbon chain lengths. The resulting complexes (each designated as N3-L-C 60 ) were characterized by FT-IR spectra, FE-SEM images, and EDX analysis. The short-circuit photocurrent density ( J sc ) of the dye-sensitized solar cells (DSSCs) using the fullerene-attached sensitizers varied markedly depending on the chain length of the linker. In the case of the linker 1,6-diaminohexane, the J sc , V oc and conversion efficiency of the pertaining cell were found to be 11.75 mA/cm 2 , 0.70 V and 4.5%, respectively, as against the values of 10.55 mA/cm 2 , 0.68 V and 4.0%, respectively, for a DSSC with ordinary N3 dye. The J sc variations are discussed on the basis of effective dye adsorptions on TiO 2 films. The possible favorable effects for V oc enhancement, caused by hydrophobic atmosphere around the TiO 2 particles due to diaminohydrocarbon chains and by the negative shift of the flat band potential of TiO 2 by NH groups, are offset by the mediation of back electron transfer by C 60 ; this phenomenon is seen as the reason for minimal V oc changes.

A ZnO-covered TiO2 (denoted as ZnO/TiO2) film was prepared by incorporating a small quantity of particulate ZnO in a TiO2 matrix by thermal chemical vapor deposition. When used in a dye-sensitized solar cell, an enhancement was observed in both short-circuit photocurrent (Jsc) and open-circuit voltage (Voc) by 12% and 17%, respectively, relative to those of a cell containing a bare TiO2 film. The observed Jsc enhancement is attributed to the increase in the surface area of the ZnO/TiO2 film, and the Voc enhancement to the formation of a potential barrier by ZnO at TiO2/electrolyte interface. The films were characterized by FE-SEM, EDX, and XRD.

Plasma source ion implantation (PSII) technique was used for the ion implantation and deposition of copper film on the polyimide. In PSII–EIAMAD (energetic ion assisted mixing and deposition) process, a polyimide film was immersed in a plasma, and high negative voltage pulses were applied to accelerate ions into the substrate resulting in the mixing effect of copper atoms with polyimide layers. This method was used to improve the adhesion between Cu layer and polyimide film depending on ion species, ion energy, and treatment time. The adhesion strength was determined by the 90° peel test. The deposited-copper surface was investigated by SEM and AFM, and the interface between Cu film and polyimide was characterized by AES. Enhancement of adhesion for PSII–EIAMAD treated copper film was observed and its interface was very gradient in AES depth profile. The Cu-deposited layers are adherent and reasonably stable after heat treatment of 24 h at 100 °C.

Anatase TiO2 nanorods and nanotubes were produced from hydrolyzed TiCl4 using an anodic alumina membrane (AAM) as template. SEM analysis indicated that the form of nanostructures depends on the pore size of the membrane, and their diameters are almost same regardless of nominal pore sizes. When the nanorods were incorporated at about 10 wt% level in a P25 TiO2 film electrode of a dye-sensitized solar cell, its solar energy conversion efficiency was enhanced by about 42% as a result of a higher short-circuit photocurrent, compared with that of a cell fabricated with bare P25. The nanostructures were characterized by SEM, energy dispersive X-ray spectroscopy and Raman spectroscopy. Reasons for the invariance of sizes of nanostructures, and for the enhancement of the solar energy conversion efficiency are discussed. These explanations are supported by SEM, dye-adsorption measurements and light scattering findings.

An efficient flexible dye-sensitized solar cells (DSSCs) using stainless steel supporting substrate for fabricating nanocrystalline TiO2 film electrodes were developed, intending to improve the photoelectrochemical properties of plastic substrate-based DSSCs. The most important advantage of a stainless steel-based TiO2 film electrode over a plastic-based electrode lies in its high-temperature sinterability. Optimal photovoltaic properties were obtained with a cell where the TiO2 film was coated on both ITO- and SiOx-sputtered stainless steel (denoted as TiO2/ITO/SiOx/StSt). The photocurrent of the flexible cells with a TiO2/ITO/SiOx/StSt electrode increased significantly, leading to a much higher overall solar conversion efficiency η of 4.2% at 100 mW/cm2, based on short-circuit photocurrent density, open-circuit voltage and fill factor of 11.2 mA/cm2, 0.61 and 0.61 V, respectively, than those reported for cells with plastic substrates.

We report a record high continuous wave (CW) output power of 250 mW for the 780 nm band AlGaAs laser. The selectively buried ridge (SBR) structure was used and each layer of the laser was designed to have the lowest defect density by using the deep level transient spectroscopy (DLTS) analyses. The laser operated at a peak wavelength of 783 nm with a threshold current of 38 mA. The stable fundamental transverse mode was observed at 100 mW, 70 °C for more than 3000 h. The far-field aspect ratio, a ratio of far-field vertical angle over far-field parallel angle to the junction plane, was measured to be 1.8, which is small enough for the high density CD-R system.

A new strategy involving the introduction of the common cationic surfactant cetyltrimethylammonium bromide (CTAB) for the cathodic deposition of titanium dioxide from hydrolyzed TiCl4 and TiCl3 solutions by cyclic voltammetry has been developed. Crack-free and non-transparent anatase TiO2 films were obtained for the first time and characterized with the aid of Raman spectra and SEM. Selection of TiCl4 as the precursor for the electrodeposition is quite a novel approach for the research in the area of dye-sensitized solar cells (DSSCs). It is noted that NO3− ion is essential for such a deposition. Under the same conditions, a thicker TiO2 film was obtained by adding CTAB into KNO3 electrolyte, compared with the case without it. The CTAB-promoted film led to an increased energy conversion efficiency of the corresponding DSSC. Mechanisms are proposed for the electrochemical deposition and the beneficial role of CTAB.

An analytical method has been developed for measuring 24 chlorinated pesticides in fish tissue samples. Extraction of chlorinated pesticides was carried out by ultrasonication using an acetone-n-hexane (5:2, v/v) mixture. Most of the lipids in the extract were eliminated by freezing-lipid filtration, prior to solid-phase extraction (SPE) cleanup. During freezing-lipid filtration, about 90% of the lipids extracted from the fish samples were easily removed without any significant losses of chlorinated pesticides. For purification, SPE using Florisil was shown to be more effective than silica. Quantification was performed using gas chromatography-mass spectrometry in the selected ion monitoring mode. Spiking experiments were carried out to determine the recovery, precision, and limits of detection (LODs) of the method. The overall recovery was above 80% in the spiked fish tissue sample at 100 ng/g level. The detection limits for chlorinated pesticides were ranged from 0.5 to 5 ppb, except for endosulfan I and II which was 20 ppb. The newly developed method is demonstrated to give efficient recoveries and LODs for detecting chlorinated pesticides spiked into fish tissue with high lipid content.

The promotional effect of CO 2 in the liquid phase oxidation of ethylbenzene to acetophenone (AP) with the Co/Mn/Br (MC-type) catalyst system has been investigated. Significant enhancement of catalytic activity was found in the presence of CO 2 and thus selectivity toward acetophenone was increased as well. UV-visible investigations of the MC-type catalyst system in the oxidation of ethylbenzene reveal that Mn(III) is more easily formed in the presence of CO 2 ; such formation would be associated with the CO 2 promotional effect.

The surface resistivity of several polymers such as poly(styrene/butadiene copolymer), modified poly(phenyleneoxide), poly(ethylene terephthalate), and polyimide was improved by the argon gas plasma source ion implantation (Ar-PSII) technique equipped with a mesh-type conducting grid. With the grid, the surface resistivities of the modified polymers decreased up to 11 orders of magnitudes at a high ion dose, and remained nearly at the same values after 3 months. The PSII treated polymer sample with the grid provided more uniformly modified surface and lower surface resistivity than that treated without the grid. The extent of the decrease in surface resistivity depended on the polymer structures and physical properties. However, the surface resistivity was independent of the sample thickness, the grid size, and the grid height. Surface analyses using scanning electron microscopy, time-of-flight secondary ion mass spectrometry, and Raman spectroscopy provided the useful information on modified surfaces.

Time-dependent change in the concentrations of some aromatic hydrocarbons with TiO2-based catalysts under irradiation was monitored by absorption spectroscopy. Titanium silicalite-2 with higher crystallinity (TS-2h) showed greater photodegradation efficiency than titanium silicalite-2 (TS-2). The greater efficiency was attributed to the increased adsorptivity based on the larger distribution coefficient arising from the more hydrophobic nature in the TS-2h cavity than in TS-2. The distribution coefficient correlates well with the slope of the Langmuir–Hinshelwood equation, and can be a useful index for the relative photodegradation efficiency of the aromatic hydrocarbon.

The mechanism of photocurrent decay with time of illumination of PbS-coated TiO2 (PbS/TiO2) photoelectrochemical cells in S2− and SO32− solution was investigated. The photocurrent decay at short circuit can primarily be attributed to the formation of PbSO4 on the surface of PbS, followed by the dissolution of PbSO4 into the aqueous solution. In the presence of pyridine or ethanol in the solution, the Jsc decay with time of illumination is reduced due to the suppression of the PbSO4 formation.

Influence of an electrodeposited overlayer and a spin-coated underlayer of TiO 2 electrode on the cell performance was studied. The effect of annealing TiO 2 electrode in O 2 atmosphere was also investigated. XRD analysis made on TiO 2 by the sol-gel method showed a pure anatase phase. Electrodeposited TiO 2 film showed two times larger surface area and O 2 annealed TiO 2 showed three times larger surface area than untreated TiO 2 , Electrodeposition of TiO 2 resulted in sub-particles on base TiO 2 and increased the surface area and the short-circuit current (J sc ) For an underlayer, TiCl 4 treatment caused no noticeable changes in current-voltage characteristics. Annealing in O 2 atmosphere did not cause any apparent changes in bonding characteristics judging from XPS measurement. A conversion efficiency up to 5.8% was obtained.

The effect of Cl− ions on the photodecomposition of 4-chlorophenol (4-CP) was investigated with and without titanium silicalite-2 (TS-2) catalyst as a function of pH by absorption spectroscopy. In the absence of TS-2, chloride ions enhance the photodegradation of 4-CP in acidic and neutral solutions under UV illumination, with a faster photodegradation in acidic solutions. In the presence of TS-2, however, chloride ions enhance the photodegradation only in acidic solutions. The results reveal that chloride ions should be in close proximity to 4-CP in order to enhance photodegradation. The enhancement can be attributed to the reaction of chloride ions with chloride radicals that are abstracted from 4-CP either by absorption of the light or by reaction with hydroxyl radicals.

The photocatalyzed degradation of 4-chlorophenol (4-CP) in water is comparatively examined with TiO 2 powder, TiO 2 /CdS powder, TiO 2 thin film electrodes and TiO 2 /CdS thin film electrodes in the initial stages of the reaction. The apparent intermediates of 4-CP photodegradation with TiO 2 and TiO 2 /CdS powders in suspensions are found to be 1,4-benzoquinone (BQ) and hydroquinone (HQ), with HQ rapidly converting into BQ with TiO 2 and TiO 2 /CdS electrodes at an applied anodic potential of 0.6 V vs Ag/AgCl. The apparent reaction rate constants using the Langmuir–Hinshelwood equation with TiO 2 /CdS powder and the TiO 2 /CdS electrode are obtained to be about 90% and 33% larger than with TiO 2 powder and the TiO 2 electrode, respectively, indicating that the TiO 2 /CdS catalysts have more photocatalytic activities than the TiO 2 catalysts in the initial stages. The adsorption coefficient ( K ) of 4-CP on TiO 2 /CdS powder is one and a half times larger than that on TiO 2 powder. With the electrode catalysts at 0.6 V, the value of K increases several times with respect to the corresponding powder catalysts and shows essentially no difference between the TiO 2 /CdS electrode and the TiO 2 electrode. Thus, the value of K may strongly depend on the electrostatic interaction between 4-CP and the electrode surface, but not very much on the type of electrode surface.

Ultrasonic agitation was applied during the chemical bath deposition of CdS thin films. Ultrasonication resulted in a dramatic difference in surface morphology, growth rate, and optical properties of CdS films. There were virtually no colloidal particles adsorbed on the surface. The surface roughness measured by atomic force microscopy was reduced by a factor of two. Band gap energy increased to 2.39 eV from 2.37 eV. X-ray patterns showed that the preferred orientation changed from hexagonal(002)/cubic(111) to hexagonal(101). Optical transmission improved in the wavelength range longer than 520 nm. The chemical reaction for CdS formation started at a lower temperature under ultrasonication, and dense films were obtained even when the chemical composition of the aqueous solution deviated far from the optimum conditions.

TiO 2 thin films were prepared on electrochemically etched porous Si by anodic oxidative hydrolysis of TiCl 3 for the purpose of solar cell application. We compared electrochemical and photoelectrochemical properties of the TiO 2 -deposited porous Si electrodes (TiO 2 /porous Si) with those of a porous Si electrode. The TiO 2 /porous Si showed prolonged stability of photoluminescence and enhancements of photovoltage and photocurrent by 0.13 V and 67% increase, respectively, in comparison with porous Si due to the reduction of surface traps for charge carriers in the presence of TiO 2 thin layer. Li + and Na + ions exhibited intercalation and deintercalation through the electrodeposited TiO 2 film.

Chemiluminescence (CL) from fluorophores generated by the reaction of bis(2,4-dinitrophenyl)oxalate (DNPO), H 2 O 2 , and several bases have been examined for the identification of multiple pathways. When the intensity of PO-CL (peroxyoxalate chemiluminescence) vs. time was measured under low base concentration in acetonitrile, two distinctive emission maxima, a fast decaying peak and a slowly decaying peak, were observed. The fast decaying first peak was predominant over the slowly varying peak at high concentration of DNPO and H 2 O 2 and at low base concentration, and might be formed by the direct reaction of hydroperoxy oxalate ester (X) and fluorophore. When another set of the intensity vs. time was measured at high base concentration in ethylacetate containing 5% tert -butylalcohol, there also appeared two different peaks, a slowly decaying peak and a sharply decaying peak. The slowly decaying peaks in both sets of experiments were produced by base-catalyzed nucleophilic reaction of DNPO with X. The sharply decaying peak in the latter experiment could be dependent on the relative basicity of the donor, X, and acceptor, base. Based on the those observations a scheme is suggested that describes three reaction pathways.

The electrochemical behavior of polypyrrole (PPy) electropolymerized within poly(acrylonitrile-co-butadiene) (PAB) was compared with that of PPy deposited on Pt in terms of cyclic voltammetry, chronoamperometry, and chronopotentiometry in acetonitrile. The PAB coating was not removed after the PPy deposition. The reduction peak potentials of a PPy ¦PAB¦Pc electrode occurred at more negative potentials than those of a PPy ¦ Pt electrode. For both electrodes anodic and cathodic peak currents were proportional to the scan rate below 100 mV s−1, but to the square root of the scan rate beyond 200 mV s−1. The apparent diffusion coefficient of ClO4− in the PPy + PAB was estimated to be 1.6 times larger than that in the PPy. The more porous and rougher structure of the PPy film grown within the PAB layer had higher anodic and cathodic currents, faster charging and discharging rates and a larger capacity.

The luminescence properties of PSMA-Ln(III) (Ln = Sm, Dy, Tb, Gd, Yb, Eu) in aqueous solution were investigated. Upon excitation of the styrene subunit, energy migrates from the PSMA polymer to Ln 3+ ions, and luminescence enhancements of Tb 3+ , Eu 3+ , Sm 3+ and Dy 3+ were observed. In PSMA-Eu 3+ , the effect of environment around the metal ion largely contributes to the luminescence enhancement. Fluorescence from PSMA in PSMA-Ln 3+ complexes was also measured. PSMA fluorescence intensity was enhanced upon coordination to Ln(III) (Ln = Sm, Dy, Tb, Gd), and λ em,max was blue-shifted due to Ln(III) association to the polymer chain and the reduced chain mobility of PSMA. In the presence of Eu 3+ and Yb 3+ , however, PSMA luminescence intensity was decreased. Compared to Tb 3+ , the unlikely low efficiency of energy transfer from styryl moieties in PSMA−Eu 3+ and diminished PSMA fluorescence intensities are attributed to the possibility of a deactivating charge transfer state due to the low reduction potentials of Eu 3+ and Yb 3+ .

The effect of inserting a PEDOT interlayer between the MEHPPV layer and the Au electrode of a nanocrystalline ITO/TiO2/MEHPPV/Au heterojunction device on the photovoltaic characteristics of the device has been studied. The MEHPPV layer has both a light-sensitizing role and a hole-transporting function. The overall conversion efficiency of the device with a PEDOT layer is better by more than 80% than that obtainable without a PEDOT layer. The modified device shows improved photocurrent density–voltage (J–V) characteristics, in that there is a strong reduction of the roll-over behavior in the forward bias region, and an increase in the fill factor. These improvements are due to the reduction of junction resistance across the MEHPPV/Au interface in the presence of the PEDOT interlayer, which results in improved hole injection.

In a hybrid photovoltaic device of ITO/TiO 2 /polymer/Au, the photocurrent was characterized with different temperature by using regio-random (P3HT) and regular (RP3HT) poly(3-hexyl thiophene)s. RP3HT showed a constant photocurrent at temperatures higher than 195 K. On the other hand, the photocurrent of the P3HT device decreased gradually below room temperature. The drift charge mobility of both types of devices was calculated by the space charge limited current (SCLC) theory using dark J-V characteristics. The phtotocurrent began to decrease below a critical mobility range of 10 -5 cm 2 /V.s.

We studied the photovoltaic device with the heterojunction hybrid structure of n-type semiconductor TiO 2 and p-type conducting polymer. poly(2-methoxy, 5-(2'-ethyl-hexoxy)-1,4-phenylenevinylene) (MEHPPV). The polymer layer has both light sensitizing and charge transporting functions. PEDOT layer inserted in the structure of [TO/TiO 2 /MEHPPV/PEDOT/Au improved the fill factor as well as the conversion efficiency The PEDOT modified device showed that the J sc , V oc , FF and η ρ were 0.64 mA/cm 2 , 0.75 V. 0.54 and 0.49%. repectively, under the illumination of 50 mW/cm 2 (AM1.5).