Nickel oxide (NiO) thin films were prepared by electrodeposition technique onto the fluorine doped tin oxide (FTO) coated glass substrates in one step deposition at 20, 30, 40 and 50
min deposition ...times respectively. The effect of film thickness (thereby microstructural changes) on their structural, morphological, optical and electrochromic properties was investigated. The mass change with potential and cyclic voltammogram was recorded in the range from +0.3 to −0.8
V versus Ag/AgCl. One step deposition of polycrystalline cubic phase NiO was confirmed from X-ray diffraction study. Optical absorption study revealed direct band gap energy of 3.2
eV. The optical transmittance of the film decreased with increase in film thickness. A uniform granular and porous morphology of the films deposited for 20
min was observed. The film becomes more compact and devoid of pores when deposition time was increased to 30
min. Thereafter severe cracks are observed. All the films exhibit anodic electrochromism in OH
− containing electrolyte (0.1
M KOH). The maximum coloration efficiency of 107
cm
2/C and electrochemical stability of up to 10
4 colour/bleach cycles were observed for the films deposited for 20
min (film thickness of 104
nm).
Storm events dominate riverine loads of dissolved organic carbon (DOC) and nitrate and are expected to increase in frequency and intensity in many regions due to climate change. We deployed three ...high‐frequency (15 min) in situ absorbance spectrophotometers to monitor DOC and nitrate concentration for 126 storms in three watersheds with agricultural, urban, and forested land use/land cover. We examined intrastorm hysteresis and the influences of seasonality, storm size, and dominant land use/land cover on storm DOC and nitrate loads. DOC hysteresis was generally anticlockwise at all sites, indicating distal and plentiful sources for all three streams despite varied DOC character and sources. Nitrate hysteresis was generally clockwise for urban and forested sites, but anticlockwise for the agricultural site, indicating an exhaustible, proximal source of nitrate in the urban and forested sites, and more distal and plentiful sources of nitrate in the agricultural site. The agricultural site had significantly higher storm nitrate yield per water yield and higher storm DOC yield per water yield than the urban or forested sites. Seasonal effects were important for storm nitrate yield in all three watersheds and farm management practices likely caused complex interactions with seasonality at the agricultural site. Hysteresis indices did not improve predictions of storm nitrate yields at any site. We discuss key lessons from using high‐frequency in situ optical sensors.
Key Points
An improved hysteresis index revealed remarkable variation in storm dynamics for 126 storms in watersheds with varied land use/land cover
Seasonality influenced storm nitrate loading; interactions between farm practices and seasonal dynamics were captured by sensors
Sites had generally anticlockwise storm hysteresis for DOC, though storm nitrate hysteresis direction varied by land use/land cover
WO3 thin films were deposited on indium doped tin oxide (ITO) substrates by R.F. sputtering and investigated for their electrochromic properties. Iono-optical studies were performed in a ...three-electrode electrochemical cell to deduce information about the intercalation kinetics. Addition of acetonitrile (AN) to the non-aqueous electrolyte is found to modify the electrolyte properties and increase the diffusion coefficient by almost two orders. The device shows a coloration efficiency (C.E.) of 46.45cm2C−1 and reversibility of 98%. The variation in color with applied potential has been plotted on xy-chromaticity diagram and chromic contrast of the device has been calculated using L*a*b* values.
Nickel oxide/polypyrrole (NiO/PPy) thin films were deposited by a two step process in which the NiO layer was electrodeposited potentiostatically from an aqueous solution of NiCl
2·6H
2O at pH 7.5 on ...fluorine doped tin oxide (FTO) coated conducting glass substrates, followed by the deposition of polypyrrole (PPy) thin films by chemical bath deposition (CBD) from pyrrole mixed with ammonium persulfate (APS). The NiO/PPy films were further characterized for their structural, optical, morphological and electrochromic properties. X-ray diffraction study indicates that the films composed of polycrystalline NiO and amorphous PPy. Infrared transmission spectrum reveals chemical bonding between NiO and PPy. Rectangular faceted grains were observed from scanning electron microscopy results. The electrochromic (EC) property of the film was studied using cyclic voltammogram (CV), chronoamperometry (CA) and optical modulation. The NiO/PPy presents superior EC properties than their individual counterparts. The coloration/bleaching kinetics (response time of few ms) and coloration efficiency (358
cm
2/C) were found to be improved appreciably. The dramatic improvement in electrochemical stability (from about 500 c/b cycles for PPy to 10,000 c/b cycles for NiO/PPy) was observed. This work therefore demonstrates a cost-effective and simple way of depositing highly efficient, faster and stable NiO/PPy electrodes for EC devices.
•Synthesis of ZnO thin films onto glass substrates at 450°C from aqueous zinc acetate solution.•The multifunctionality of spray deposited ZnO thin films was investigated.•Gas sensing performances ...toward three gases (ethanol, propanol and acetone) were investigated.
Simple and economical spray pyrolysis technique (SPT) was employed for synthesis of multifunctional zinc oxide (ZnO) thin films onto glass substrates. The synthesized material was composed of Zn2p and O1s, as confirmed from X-ray photoelectron spectroscopy (XPS). Field emission scanning electron microscopy (FESEM) image revealed the uniform distribution of grains of about 80–90nm. The film shows superhydrophobic nature with contact angle (CA) value 154°. The deposited film was specular and highly transparent with average transmittance of about 85%. The optical transmittance spectrum shows sharp band edge at 381nm, corresponding to band gap energy of 3.25eV. Film exhibits room temperature photoluminescence (PL) with a strong ultraviolet emission at 398nm with weak green emission at 520nm, confirms the less defect density in the samples. The gas sensing performance of the spray deposited ZnO films toward to reducing gases like ethanol, propanol and acetone was also studied. We examined here the viability of SPT in order to deposit such multifunctional ZnO thin films on glass substrates, which can be useful for various applications.
Nickel oxide thin films were grown onto FTO-coated glass substrates by a two-step process: electrodeposition of nickel sulphide and their thermal oxidation at 425, 475 and 525
°C. The influence of ...thermal oxidation temperature on structural, optical, morphological and electrochromic properties was studied. The structural properties undoubtedly revealed NiO formation. The electrochromic properties were studied by means of cyclic voltammetry. The films exhibited anodic electrochromism, changing from a transparent state to a coloured state at +0.75
V versus SCE, i.e. by simultaneous ion and electron ejection. The transmittance in the coloured and bleached states was recorded to access electrochromic quality of the films. Colouration efficiency and electrochromic reversibility were found to be maximum (21
mC/cm
2 and 89%, respectively) for the films oxidized at 425
°C. The optical band gap energy of nickel oxide slightly varies with increase in annealing temperature.
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► We investigated WO
3 and PANI dual and complementary device for smart window application. ► We studied its limitations in terms of inorganic–organic electrochromic. ► The change in ...transmittance of WO
3 film was found to be 63.92%. PANI film showed an optical attenuation of 50.69% while the transmission change through the IOECD was equal to 57%. ► Also noted that even though the coloration efficiency increases with respect to the working electrode, it decreases with reference to the counter electrode. ► Charge unbalanced of dual complementary device, the coloration efficiency is always less than that of one of the constituent electrodes.
Inorganic tungsten oxide (WO
3) and organic polyaniline (PANI) films were used as the cathodic and anodic electrodes of an inorganic–organic electrochromic device (IOECD). WO
3 was deposited by sputtering while PANI films were electrodeposited on transparent Indium doped Tin Oxide (ITO) glass substrates, respectively. Optical and electrochemical studies were performed to find the optical attenuation, coloration efficiencies, reversibility and response time separately for the individual films as well as for the assembled IOECD. The change in transmittance of WO
3 film was found to be 63.92%. PANI film showed an optical attenuation of 50.69% while the transmission change through the IOECD was equal to 57%. Colorimetric analysis was done to define the colors in the bleached and colored states in terms of
L*
ab values and
xy chromaticity diagram. Factors limiting the performance of an IOECD were analyzed. It was found that in a charge unbalanced dual complementary IOECD, the coloration efficiency is always less than that of one of the constituent electrodes.
▶ Nano-crystalline zinc oxide thin films were electrosynthesized from an aqueous zinc acetate Zn(CH
3COO)
2·2H
2O solution onto FTO coated conducting glass substrates using two different ...electrochemical routes, namely (i) without an organic surfactant and (ii) with an organic surfactant, viz. PVA (poly-vinyl alcohol) or SDS (sodium dodecyl sulfate). ▶ The reproducibility of the catalytic activity of the SDS and PVA surfactants in the modification of the morphologies was observed. ▶ Vertically aligned nest-like and compact structures were observed from the SDS and PVA mediated films, respectively, while the grain size in the ZnO thin films without an organic surfactant was observed to be ∼150
nm. ▶ The dye sensitized ZnO electrodes displayed excellent properties in the conversion process from light to electricity. The efficiencies of the surfactant mediated nanocrystalline ZnO thin films, viz. ZnO:SDS and ZnO:PVA, sensitized with ruthenium-II (N3) dye were observed to be 0.49% and 0.27%, respectively.
Nano-crystalline zinc oxide thin films were electrosynthesized with an aqueous zinc acetate Zn(CH
3COO)
2·2H
2O solution on to FTO coated glass substrates. Two different electrochemical baths were used, namely (i) without an organic surfactant and (ii) with an organic surfactant, viz. PVA (poly-vinyl alcohol) and SDS (sodium dodecyl sulfate). The organic surfactants played an important role in modifying the surface morphology, which influenced the size of the crystallites and dye-sensitized solar cell (DSSC) properties. The vertically aligned thin and compact hexagonal crystallites were observed with SDS mediated films, while the grain size in the films without an organic surfactant was observed to be ∼150
nm. The conversion efficiencies of the ZnO:SDS:Dye and ZnO:PVA:Dye thin films were observed to be 0.49% and 0.27%, respectively.
Mammalian cells contain potent activity for removal of 3′-phosphoglycolates from single-stranded oligomers and from 3′ overhangs of DNA double strand breaks, but no specific enzyme has been ...implicated in such removal. Fractionated human whole-cell extracts contained an activity, which in the presence of EDTA, catalyzed removal of glycolate from phosphoglycolate at a single-stranded 3′ terminus to leave a 3′-phosphate, reminiscent of the human tyrosyl-DNA phosphodiesterase hTdp1. Recombinant hTdp1, as well asSaccharomyces cerevisiae Tdp1, catalyzed similar removal of glycolate, although less efficiently than removal of tyrosine. Moreover, glycolate-removing activity could be immunodepleted from the fractionated extracts by antiserum to hTdp1. When a plasmid containing a double strand break with a 3′-phosphoglycolate on a 3-base 3′ overhang was incubated in human cell extracts, phosphoglycolate processing proceeded rapidly for the first few minutes but then slowed dramatically, suggesting that the single-stranded overhangs gradually became sequestered and inaccessible to hTdp1. The results suggest a role for hTdp1 in repair of free radical-mediated DNA double strand breaks bearing terminally blocked 3′ overhangs.
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