Anode Engineering of Highly Efficient Polymer Solar Cells Using Treated ITO

ITO substrates were treated with organic solvent cleaning(OSC), SC1 treatment[V(NH₄OH):V(H₂O₂): V(H₂O)=1:1:5], O₂ plasma and UV ozone, respectively. Combined investigations of atom force microscopy(AFM), water contact angle measurements, ultraviolet photoemission spectroscopy(UPS) and X-ray photoemission spectroscopy(XPS) demonstrated that UV ozone treatment could give rise to the smoothest surface, the most hydrophilic property and the highest work function(WF) of ITO due to the removal of hydrophobic C-O impurity from the ITO surface and the enrichments of more oxygen on the ITO surface. When PEDOT:PSS film[(poly(3,4-ethylenedioxy- thiophene):poly(styrene sulfonate)] was deposited on the ITO substrates treated with UV ozone, it showed a lower root-mean- square roughness in AFM images, a higher transmission in UV-Vis transmission spectra and a higher WF in UPS spectra than the PEDOT:PSS films deposited on the ITO substrates treated by other three methods. As a result, the power conversion efficiency of polymer solar cells(PSCs) based on PTB7:PC₇₁BM as an active layer and ITO treated by UV ozone as an anode can reach 8.48% because of the simultaneously improved short circuit current, open circuit voltage and fill factor compared to the PSCs with ITO treated with other three methods.     

Infrared spectroscopic characterization of the buried interface and surfaces of bonded silicon wafers

Basic investigations have been carried out on the characterization of different processing steps in bond preparation using etched <111> faces of silicon wafers for the incidence of the infrared beam to a multiple internal reflection geometry. The method is very sensitive to the surface coverage and interface. Surface activation by RCA cleaning yields an increase of water coverage and a decrease of SiH and CH groups. The detection limit for an oxide layer between silicon wafers has been found to be about 3 nm. Received: 18 July 1997 / Revised: 15 August 1997 / Accepted: 19 August 1997     

Chemical stability of (NH4)2S-passivated InP(001) surfaces – investigations by XPS and XPD

UV/ozone supported surface oxidation of wet chemically cleaned and sulfurized InP(001) was investigated using XPS in order to study the chemical stability of (NH₄)₂S-passivated surfaces. Sulfur coverages of about one monolayer thickness were not sufficient to completely passivate the InP surface against oxidation. Similar oxides of the substrate components were observed at the surfaces. Evidence for surface passivation was found in the chemical stability of incorporated sulfur (In-S bonds), the lower growth rate of the oxide layer and its reduced thickness at comparably large UV/ozone exposures. The oxide layer was found to be amorphous at all stages of the oxidation process, as was proved by X-ray photoelectron diffraction.     

The role of ions and UV radiation in gallium arsenide etching process

The mechanism of gallium arsenide etching in a chlorine-argon plasma was studied. The absorption-desorption model was proposed which explains an increase in etching rate upon chlorine dilution with argon by enhancement of the efficiency of active site cleaning with plasma UV radiation and ion fluxes. The processes of desorption of etching products from the surface by ions and UV photons were shown to be energetically favored. The amount of active sites cleaned per ion or photon was calculated. The addition of argon was assumed to change the proportion of active sites. Procedures for calculating fluxes of reactive species onto the surface and the probability of ultraviolet light and ion-induced desorption were detailed.     

Determination and confirmation of the amnesic shellfish poisoning toxin, domoic acid, in shellfish from Scotland by liquid chromatography and mass spectrometry

During 1998 and early 1999, shellfish samples from sites in Scotland were found to contain the amnesic shellfish poisoning toxin, domoic acid (DA). Two different techniques, liquid chromatography (LC) with UV diode-array detection and LC with mass spectrometric (MS) detection, were used to detect and confirm DA in shellfish extracts. The LC/UV method was validated for routine monitoring by recovery experiments on spiked mussel and scallop tissues with a certified mussel tissue used as reference material. Crude extracts of selected samples as well as extracts cleaned with strong anion exchange (SAX) were analyzed by both LC/UV and LC/MS. Good correlation (linear regression r2 = 0.996, slope = 0.93) between the 2 methods was found for cleaned extracts. Analyses of crude extracts by LC/UV produced false-positive results in 2 crab samples, whereas LC/MS analyses gave accurate results. It was concluded that LC/UV is a valid approach for routine monitoring of DA in shellfish when cleanup is performed with a SAX cartridge to prevent false positives. A variety of shellfish species were surveyed for DA content, including Pecten maximus (king scallops), Chlamys opercularis (queen scallop), Mytilus edulis (blue mussels), Cancer pugaris (crab), and Ensis ensis (razor fish). The highest concentration of DA was 105 microg/g in Pecten maximus.     

Functionalization of indium tin oxide

The preparation and functionalization of ITO surfaces has been studied using primarily X-ray photoemission spectroscopy and infrared reflection-absorption spectroscopy (IRRAS) and the reagents n-hexylamine and n-octyltrimethoxysilane (OTMS). Particular attention has been paid to characterization of the surfaces both before and after functionalization. Surfaces cleaned by ultraviolet (UV)/ozone treatment and subsequently exposed to room air have approximately 0.5-0.8 monolayers (ML) of adsorbed impurity C. Most is in the form of aliphatic species, but as much as one-half is partially oxidized and consists of C-OH, C-O-C, and/or >C=O groups. The coverage of these species can be reduced by cleaning in organic solvents prior to UV/ozone treatment. The OH coverage on the ITO surfaces studied here is relatively small (approximately 1.0 OH nm-2), based on the Si coverage after reaction with OTMS. A satellite feature in the O 1s XPS spectrum, often suggested to be a quantitative measure of adsorbed OH, receives a significant contribution from sources not directly related to hydroxylated ITO. n-Hexylamine adsorbs, at a saturation coverage of approximately 0.08 ML, via a Lewis acid-base interaction. The particular acid site has not been conclusively identified, but it is speculated that surface Sn sites may be involved. For OTMS, a saturation coverage of about 0.21 ML is found, and the C/Si atom ratios suggest that some displacement of preadsorbed organic impurities occurs during adsorption. The alkyl chain of adsorbed OTMS is disordered, with no preferred stereoisomer. However, the chain appears to lie mainly parallel to the surface with the plane defined by the terminal CH3-CH2-CH2- segment oriented essentially perpendicular to the surface.     

Cleaning requirements for silica‐coated sensors used in optical waveguide lightmode spectroscopy

Optical waveguide lightmode spectroscopy (OWLS), based on the incoupling of laser light into a waveguide sensor by an optical grating, allows for the in situ measurement of protein adsorption. Few reports have described cleaning methods for the surfaces of such sensors, and in this investigation, we compare common methods for cleaning of silica surfaces in relation to their effectiveness for cleaning silica‐coated waveguide sensors used in OWLS. For this purpose, atomic force microscopy (AFM) analysis of surface morphology and OWLS detection of protein adsorption kinetics were used to evaluate waveguide sensors before and after cleaning. While AFM line scans showed a substantial increase in average waveguide peak‐to‐valley height after RCA cleaning relative to all other methods tested, chemical etching owing to the alkaline component of the rolling circle amplification method rendered the waveguide unusable for detection of protein adsorption with OWLS. A revised method, based on replacement of the alkaline step with immersion in sodium dodecyl sulfate, was not only effective at cleaning OWLS waveguides off‐the‐shelf but also showed excellent protein adsorption reproducibility after ex situ cleaning. Moreover, the revised method showed excellent reproducibility when applied in situ, between repeated adsorption‐elution cycles. Copyright © 2013 John Wiley & Sons, Ltd.     

Decomposition reaction of organophosphorus nerve agents on solid surfaces with atmospheric radio frequency plasma generated gaseous species

The decomposition and detoxification of compounds are of great interest in environmental protection and defense-related areas. We report the generation of gaseous excited species by scanning atmospheric radio frequency (rf) plasma and their reactions with two representative organophosphorus nerve agents, paraoxon and parathion, deposited on solid surfaces. The excited gaseous species generated in the Ar and Ar/O2 plasma were identified as atomic oxygen, OH radical, and excited nitrogen molecule from optical emission spectroscopy analysis. The reaction of these species with paraoxon and parathion was monitored with reflection-absorption infrared spectroscopy and compared with the decomposition by UV irradiation and UV/ozone treatments. The decomposition products of the atmospheric rf plasma treatment were similar to those of the UV/ozone treatment. The atomic oxygen and excited OH species generated by the plasma appear to be responsible for the oxidation of paraoxon and parathion. The plasma-induced decomposition process was much faster and more efficient than the UV/ozone process. The complete detoxification of paraoxon and parathion upon a short time exposure to the Ar/O2 plasma was confirmed by the Drosophila melanogaster culture test.     

Cleaning Away the Oleic Acid Contaminant from Glass Surface by Negative Glow Plasma

Glass surfaces are contaminated by exposure to overheated oleic acid vapor and then cleaned by low-pressure plasma of a dc glow discharge in either air or argon. In this study, the oleic acid is used as model for hydrophobic organic contaminant and glass as a model for inorganic hydrophilic substrate. The processes of contamination and plasma cleaning are studied by atomic force microscopy (AFM), which revealed formation of oleic acid nanodroplets during contamination and, then, their removal during a few minutes of plasma cleaning. Water contact angle measurements show a much faster effect of plasma cleaning treatment, the contaminated surface changing from slightly hydrophobic to superhydrophilic in less than 30 s. This effect can be attributed to oxidation and hydroxylation of the oleic acid, as indicated by infrared absorption measurements. Also, the AFM indentation of the oleic acid nanodroplets after short plasma treatment indicates solidification of the remnant contaminant material.     

Surface modification of poly(methyl methacrylate) for improved adsorption of wall coating polymers for microchip electrophoresis

The development of rapid and simple wall coating strategies for high-efficiency electrophoretic separation of DNA is of crucial importance for the successful implementation of miniaturized polymeric DNA analysis systems. In this report, we characterize and compare different methods for the chemical modification of poly(methyl methacrylate) (PMMA) surfaces for the application of wall coating polymers. PMMA surfaces coated with 40 mol% diethylacrylamide and 60 mol% dimethylacrylamide are compared to the PMMA surfaces first oxidized and then coated with hydroxypropylmethyl-cellulose or poly(vinyl alcohol) (PVA). PMMA oxidation was accomplished with UV/ozone or an aqueous solution of HNO(3) to yield hydrogen-bond donors for the spontaneous adsorption of the coating polymers. Contact angle measurements of UV/ozone exposed PMMA surfaces indicate increase in hydrophilicity, and polymer coated surfaces show a strong dependence on the coating polymer and the oxidation method. Fast and repeatable electrophoretic separations of a 10-base and 20-base DNA ladder were performed in PMMA micro CE devices. All analyses were completed in less than 10 min, resulting in the number of theoretical plates as high as 583 000 in a 7.7 cm long separation channel. The duration of UV/ozone treatment was found to have a considerable impact on separation performance. The microchips irradiated with UV for 10 min and coated with PVA as well as the microchips treated with HNO(3) and coated with HPMC were found to have the best separation performance. These results demonstrate facile and robust methods for the surface modification of PMMA enabling low-cost single use devices for electrophoretic DNA separations.     

Determination of halofuginone in bovine plasma by competing-ion high performance liquid chromatography after solid phase extraction

A high performance liquid chromatography (HPLC) method for the determination of the anticoccidial and antitheilerial drug halofuginone in bovine plasma was developed. Samples were diluted with acetic acid (10%, v/v) and cleaned up on a Bond Elut C8 column. The analyte was eluted from the extraction column and chromatographed by reversed-phase HPLC using decylamine as a competing-ion reagent. Detection was by UV at 243 nm. Recovery from plasma was 75%, and within-day and between-day coefficients of variation were 5.23 and 6.35% respectively. The specificity and sensitivity of this method (limit of detection in plasma, 1 ng/mL) were sufficiently high to enable us to characterize the time course of the drug in plasma after oral administration of therapeutic doses to cattle.     

Monomolecular reassembly of a crystalline bacterial cell surface layer (S-layer) on untreated and modified silicon surfaces

Scanning force microscopy was used to investigate the recrystallization of isolated bacterial cell surface layer (S-layer) proteins of Bacillus stearothermophilus NRS 2004/3a variant V1 on untreated, cleaned, silanized and photoresist-coated silicon wafers. With the exception of the hydrophilic surface of cleaned wafers, all other surfaces showed hydrophobic surface characteristics. Recrystallization occurred only at the hydrophobic surfaces, and, with respect to the bacterial cell, the S-layer was always oriented with its more hydrophobic outer face against the interface. Monolayer formation was initiated by crystal growth from several distant randomly oriented nucleation points and terminated by neighbouring, also growing, crystalline areas. The size of the individual crystalline domains formed in this way was in the range of 5–10 μm in diameter. The entire silicon surface was covered by a coherent monolayer after a recrystallization time of approximately 1 h.     

Crystal-face-selective adsorption of Au nanoparticles onto polycrystalline diamond surfaces

Crystal-face-selective adsorption of Au nanoparticles (AuNPs) was achieved on polycrystalline boron-doped diamond (BDD) surface via the self-assembly method combined with a UV/ozone treatment. To the best of our knowledge, this is the first report of crystal-face-selective adsorption on an inorganic solid surface. Hydrogen-plasma-treated BDD samples and those followed by UV/ozone treatment for 2 min or longer showed almost no adsorption of AuNP after immersion in the AuNP solution prepared by the citrate reduction method. However, the samples treated by UV/ozone for 10 s showed AuNP adsorption on their (111) facets selectively after the immersion. Moreover, the sample treated with UV/ozone for 40-60 s showed AuNP adsorption on the whole surface. These results indicate that the AuNP adsorption behavior can be controlled by UV/ozone treatment time. This phenomenon was highly reproducible and was applied to a two-step adsorption method, where AuNPs from different batches were adsorbed on the (111) and (100) surface in this order. Our findings may be of great value for the fabrication of advanced nanoparticle-based functional materials via bottom-up approaches with simple macroscale procedures.     

Application of heat-activated peroxydisulfate process for the chemical cleaning of fouled ultrafiltration membranes

Na Cl O has been widely used to restore membrane flux in practical membrane cleaning processes, which would induce the formation of toxic halogenated byproducts. In this study, we proposed a novel heatactivated peroxydisulfate(heat/PDS) process to clean the membrane fouling derived from humic acid(HA). The results show that the combination of heat and PDS can achieve almost 100% recovery of permeate flux after soaking the HA-fouled membrane in 1 mmol/L PDS solution at 50 °C for 2 h, which is att...     

UF of pulp and paper effluent: membrane fouling-prevention and cleaning

Effluent arriving from the Mondi Kraft paper mill at Piet Retief, South Africa, was filtered through tubular poly(ether sulphone) (PES) ultrafiltration membranes under constant pressure cross-flow conditions. The effluent that was fed into the membranes and permeate produced during filtration were characterised by UV–VIS light-spectroscopy. Substances that absorbed onto membranes during filtration caused changes to the permeability characteristics of the membranes. Changes in membrane performance were monitored by pure-water and product flux (pf) measurements.A colourimetric staining technique was developed to determine the nature of foulants adsorbed onto the membranes. Membrane cleaning solutions were subsequently selected using information obtained from the characterisation studies. In addition, the anti-fouling potential of non-covalently attached coating materials was investigated as a possible membrane pretreatment technique. Results showed that foulants present in the effluent are of phenolic and hydrophobic nature. Increasing the hydrophilic characteristics of membranes prior to filtration could reduce the amount of organic foulants that adsorbed onto the membranes. Membrane pretreatment not only reduced fouling, but also improved the effectiveness of cleaning methods. Membranes were effectively cleaned by a combination of mechanical and chemical cleaning techniques.     

Decomposition of linear dodecylbenzenesulfonate by simultaneous treatment with ozone and ultraviolet irradiation: rapid disappearance of formed mutagens.

The decomposition products and mutagenic activity in Salmonella typhimurium strains TA98, TA100 and TA104 in the presence and absence of S9 mix of linear dodecylbenzenesulfonate (DBS) in aqueous solution after ozone treatment alone or simultaneous treatment with ozone and ultraviolet (UV) irradiation (ozone/UV treatment) were investigated. The decomposed DBS solutions after these treatments for 4 h were mutagenic for strains TA98, TA100 and TA104 both with and without S9 mix, but this mutagenicity disappeared rapidly during further ozone/UV treatment. Mutagenicity of the decomposed solution of DBS, however, was not substantially decreased by treatment with ozone alone. Formaldehyde and glyoxal were identified as the decomposition products of DBS in water by high-performance liquid chromatography after treatment with 2,4-dinitrophenylhydrazine. Although these two compounds were mutagenic for strain TA104 both with and without S9 mix, they disappeared after further ozone/UV treatment but not after ozone treatment alone. These results indicate that ozone/UV treatment is an effective procedure for purifying drinking water.     

Systematic parameter screening for capillary electrophoresis monitoring of surfactants on silicon wafer surfaces by designed experiments

The surface purity of silicon wafers is an important parameter to monitor for yield improvement of semiconductor devices in a production line. Surfactants are used to reduce the surface potential in order to facilitate the removal or cleaning of particles and metals. Traces of surfactant residues from the cleaning bath may still be present on the wafer surface after the final cleaning step. In this report, two capillary electrophoresis (CE) methods for the analysis of dodecylbenzene sulfonate (DBS) are developed for monitoring the surfactant residues in the wafer manufacturing process. One method is developed for the sensitive determination of all DBS homologues and isomers in one single peak. Another method is developed for the fingerprint analysis of the homologues and isomers of DBS. The Taguchi methodology was used as a systematic optimization tool for the DBS analysis by CE. The experiments were evaluated by calculating the signal-to-noise ratio values with four responses. The lowest detection limit for DBS was 15 microg/L at 95% confidence level. The percent recovery of surfactant was between 90% and 110%.     

介孔SBA-15中有机模板剂的紫外/臭氧法脱除

紫外/臭氧法用于脱除有序介孔材料SBA-15中有机模板剂. 该方法是一种非加热光化学降解法, 简单、易操作, 可在温和条件下彻底除去SBA-15中三嵌段共聚物有机模板剂P123. 通过XRD, TEM, FT-IR和BET等对SBA-15经不同方法脱除模板剂前后的详细表征, 表明紫外/臭氧法在彻底脱除SBA-15中有机模板剂后, 保留了很好的骨架有序性, 比表面积更大, 孔道更加开放, 克服了高温焙烧脱除模板剂造成的孔道收缩.     

Ultrathin silica films immobilized on gold supports: fabrication, characterization, and modification

A novel method for covalent attachment of ultrathin silica films (thickness <10 nm) to gold substrates is reported. Silica layers were prepared using spin-coating of sol-gel precursor solutions onto gold substrates that were cleaned and oxidized using UV photo-oxidation in an ozone atmosphere. The gold oxide layer resulting from this process acts as a wetting control and adhesive agent for the ultrathin silica layer. Control of silica layer thickness between approximately 6 and 60 nm through modification of precursor solution composition or by repetitive deposition is demonstrated. Films were characterized using infrared spectroscopy, ellipsometry, atomic force microscopy, and cyclic voltammetry. For the standard deposition parameters developed here, films were determined to be 5.5 +/- 0.75 nm thick, and were stable in aqueous solutions ranging in pH from 2 to 10 for at least 30 min. Films contained nanoscopic defects with radii of 相似文献   

紫外/臭氧法在脱除沸石有机模板剂中的应用

选取LTA, FAU, BETA, MFI和MEL型沸石, 研究紫外/臭氧法在沸石有机模板剂脱除中的应用, 并与传统高温焙烧法比较, 考察两种方法对有机模板剂的脱除能力. 采用XRD, FT-IR, BET等方法对脱除模板剂前后的沸石样品进行表征, 结果表明紫外/臭氧法是一种低温有效除去沸石模板剂的方法. Beta, silicalite-1和silicalite-2沸石在紫外光照后相应的模板剂四乙基氢氧化铵、四丙基氢氧化铵和四丁基氢氧化铵已彻底脱除, A和Y型沸石中分别有27.5和6.2 wt%的四甲基氢氧化铵模板剂残留, 这主要是受其特殊β笼结构的限制而引起的.