The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Jaime C. Grunlan - One of the best experts on this subject based on the ideXlab platform.
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shift Time polyelectrolyte multilayer assembly fast film growth and high gas barrier with fewer layers by adjusting Deposition Time
ACS Macro Letters, 2014Co-Authors: David A Hagen, Brendan Foster, Bart Stevens, Jaime C. GrunlanAbstract:In an effort to reduce Deposition Time and number of layers needed to achieve high gas barrier, multilayer films were deposited using 1 s exposures for the first four bilayers (BLs) and 1 min for subsequent dips. Thin-film assemblies of polyethylenimine (PEI) and poly(acrylic acid) (PAA) were deposited onto poly(ethylene terephthalate) [PET] using the layer-by-layer Deposition process. Varying the exposure Time of PET to polyelectrolyte solutions (i.e., dip Time) significantly alters the growth rate of the multilayer thin films. The PEI/PAA system grows linearly with 1 s dip Times and exponentially with longer Times. Eight bilayers (650 nm) were required to achieve an undetectable oxygen transmission rate (<0.005 cm3/(m2·day)) using 1 min Deposition steps, but this barrier was obtained with only 6 BLs (552 nm) using 1s Deposition of the initial layers, reducing total Deposition Time by 73%. This “shift-Time” concept makes layer-by-layer assembly much faster and more commercially feasible.
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improving the gas barrier property of clay polymer multilayer thin films using shorter Deposition Times
ACS Applied Materials & Interfaces, 2014Co-Authors: Fangming Xiang, Ping Tzeng, Justin S. Sawyer, Oren Regev, Jaime C. GrunlanAbstract:Relatively fast exposure Times (5 s) to aqueous solutions were found to improve the gas barrier of clay–polymer thin films prepared using layer-by-layer (LbL) assembly. Contrary to the common belief about Deposition Time (i.e., the longer the better), oxygen transmission rates (OTRs) of these nano-brick-wall assemblies are improved by reducing exposure Time (from 1 min to 5 s). Regardless of composition, LbL films fabricated using shorter Deposition Time are always thicker in the first few layers, which correspond to greater clay spacing and lower OTR. A quadlayer (QL) assembly consisting of three repeat units of branched polyethylenimine (PEI), poly(acrylic acid) (PAA), PEI and montmorillonite (MMT) clay is only 24 nm thick when deposited with 1 min exposure to each ingredient. Reducing the exposure Time of polyelectrolytes to 5 s not only increases this film thickness to 55 nm but also reduces the oxygen transmission rate (OTR) to 0.05 cm3/(m2 day atm), which is 2 orders of magnitude lower than the same...
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influence of Deposition Time on layer by layer growth of clay based thin films
Industrial & Engineering Chemistry Research, 2010Co-Authors: Youhao Yang, Frank A Malek, Jaime C. GrunlanAbstract:The influence of Deposition Time on film growth of montmorillonite (MMT) or laponite (LAP) clay paired with branched polyethylenimine (BPEI) is studied here using layer-by-layer (LbL) assembly. Deposition Times from 5 to 300 s in each ingredient were evaluated with respect to thickness, mass deposited, film structure, and oxygen barrier. Ellipsometry and quartz crystal microbalance show the BPEI/LAP system to be more dip-Time dependent than the BPEI/MMT system because LAP platelets have a much smaller aspect ratio than MMT. Similar thickness is achieved for all recipes when only the BPEI Deposition Time is varied. Cross-sectional TEM images confirm thicker growth of BPEI/LAP in 300 s relative to 10 s. X-ray diffraction (XRD) suggests the gallery spacing between clay layers is insensitive to dip Time, which is a key structural parameter linked to both mechanical and transport properties of these types of films. Additionally, oxygen transmission rates (OTR) are below the detection limit of commercial instru...
F Gode - One of the best experts on this subject based on the ideXlab platform.
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synthesis structural optical electrical and thermoluminescence properties of chemically deposited pbs thin films
Journal of Luminescence, 2014Co-Authors: F Gode, Emine Guneri, Fatih Mehmet Emen, Emir V Kafadar, S UnluAbstract:Abstract PbS thin films with Deposition Times of 100, 115, 130 and 145 min were prepared by chemical bath Deposition method at room temperature. Their crystal structures were characterized by X-ray diffraction. All films were polycrystalline with a cubic rock salt structure. The morphological properties of the films were investigated by scanning electron microscopy. The optical properties of the films were studied using the absorbance, transmittance and reflectance spectra. The optical band gap of the films decreased from 2.65 eV to 2.50 eV with increasing Deposition Time. The optical parameters of the materials such as refractive index, extinction coefficient and dielectric constants were also determined. The electrical conductivity of the PbS film increased from 1.791×10 −6 to 1.655×10 −3 (Ω cm) −1 with increasing Deposition Time. Thermoluminescence intensity of the films was measured after irradiating the films with a β source for 15 min at room temperature and the kinetic parameters were obtained by using the computer glow curve deconvolution method.
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effect of Deposition Time on structural electrical and optical properties of sns thin films deposited by chemical bath Deposition
Applied Surface Science, 2010Co-Authors: Emine Guneri, C Ulutas, F Kirmizigul, G Altindemir, F Gode, C GumusAbstract:The effect of Deposition Time on the structural, electrical and optical properties of SnS thin films deposited by chemical bath Deposition onto glass substrates with different Deposition Times (2, 4, 6, 8 and 10 h) at 60 ◦C were investigated. The obtained films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and optical absorption spectra. All deposited films were polycrystalline and had orthorhombic structure with small crystal grains. Their microstructures had changed with Deposition Time, and their compositions were nearly stoichiometric. Electrical parameters such as resistivity and type of electrical conduction were determined from the Hall Effect measurements. Hall Effect measurements show that obtained films have p-type conductivity and resistivity values of SnS films have changed with Deposition Time. For allowed direct, allowed indirect, forbidden direct and forbidden indirect transitions, band gap values varied in the range 1.30–1.97 eV, 0.83–1.36 eV, 0.93–1.49 eV and 0.62–1.23 eV, respectively. © 2010 Elsevier B.V. All rights reserved.
Mardali Yousefpour - One of the best experts on this subject based on the ideXlab platform.
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structural and corrosion characterization of hydroxyapatite zirconium nitride coated az91 magnesium alloy by ion beam sputtering
Applied Surface Science, 2017Co-Authors: Seyed Rahim Kiahosseini, A Afshar, M M Larijani, Mardali YousefpourAbstract:Abstract The adhesion of hydroxyapatite (HA) as a coating for the AZ91 magnesium alloy substrate can be improved by using the sputtering method and an intermediate layer, such as ZrN. In this study, HA coatings were applied on ZrN intermediate layers at a temperature of 300 °C for 180, 240, 300, 360, and 420 min by ion beam sputtering. A profilometer device was used to study the HA coating thickness, which changed from 2 μm for the 180-min Deposition to 4.7 μm for 420-min Deposition. The grazing incidence X-ray diffraction analysis method and the Williamson–Hall analysis were used for structural investigation. As the Deposition Time increased, the crystalline size increased from 50 nm to 690 nm. However, given sufficient Time for stress relief on the coating structure, the lattice strain values were close to zero. Energy-dispersive X-ray spectroscopy results showed that the Ca/P ratio ranged from 1.73 to 1.81. The external indentation method was used to evaluate the coating adhesion to the substrate. The slope of curve for applied force changes versus the radius of cracks in the coating (dP/dr) varied in the range of 0.2–0.07 by the Deposition Time, indicating that the adhesion increased with the increase in coating thickness. The potentiodynamic polarization technique was used to study the corrosion behavior. With increasing Deposition Time, the corrosion potential of samples did not show a significant change, and the corrosion potential of all samples (coated and uncoated substrates) was more positive than approximately 55 mV. When the Deposition Time increased to 360 min, the corrosion current density decreased from 5.5 μA/cm2 to 0.33 μA/cm2. After 420 min of Deposition, the current density increased to 8.2 μA/cm2. Scanning electron microscopy images of the HA surface layer after 420 min clearly showed cracks on the coating surface, which led to the increase in corrosion current density.
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nano crystalline growth of electrochemically deposited apatite coating on pure titanium
Journal of Electroanalytical Chemistry, 2006Co-Authors: Mardali Yousefpour, Abdollahe Afshar, Xiudong Yang, B C Yang, Jiyong Chen, Xingdong ZhangAbstract:Abstract Hydroxyapatite (HA) coatings were deposited on commercially pure titanium plates using a hydrothermal–electrochemical Deposition method in an electrolyte containing calcium and phosphate ions. The Deposition conditions used in this study were the followings: electrolyte temperature (33–80 °C), current density (1–8 mA/cm 2 ), and Deposition Time (10–120 min). Needle-like and granular crystals of apatite coating were created with different concentrations of calcium (0.0021–0.042 M) and phosphate (0.00125–0.025 M) salts. The size of HA crystals of the coating was considerably changed with different concentration of calcium and phosphate salts, temperature of the electrolyte, and Deposition Time. The shape of HA crystals of the coating remarkably was altered by changing the concentration of calcium and phosphate salts, and current density. Multivariate analysis revealed that both size and shape of the hydroxyapatite crystals had been regulated accurately by systematic control of those above factors. These results, showed that hydrothermal–electrochemical Deposition of apatite coating takes place in two steps: nucleation and crystal growth, which strongly depended on the current density, concentrations of calcium and phosphate salts, the temperature of electrolyte, Deposition Time. Also it was revealed that preferential growth direction there is along the (0 0 2) planes of nano-scale and columnar structures of the electrochemical deposited apatite coating on titanium substrate. The cell culture experiment showed the cell adherence on the coatings was well. No floating cells were observed after 4 days. The HA Deposition was of benefit to the cell proliferation on the surface of titanium substrate.
Jin Hyeok Kim - One of the best experts on this subject based on the ideXlab platform.
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fabrication of sputtered deposited cu2sns3 cts thin film solar cell with power conversion efficiency of 2 39
Journal of Alloys and Compounds, 2017Co-Authors: A C Lokhande, Inyoung Kim, Uma V Ghorpade, M P Suryawanshi, Jin Hyeok KimAbstract:Abstract Cu 2 SnS 3 (CTS) thin film solar cell with power conversion efficiency (PCE) of 2.39% is fabricated using sputtered metallic Cu/Sn stacked precursors subjected to sulfurization. The crystal structure, phase purity, atomic composition, oxidation state, external quantum efficiency, optical and electrical properties of the thin films are characterized in detail using X-ray diffraction (XRD), Raman spectroscopy, X-ray fluorescence (XRF) spectroscopy, X-ray photoelectron spectroscopy (XPS), a quantum efficiency study, UV–visible and a hall measurement system, respectively. The influence of various Cu Deposition Time on the structural, compositional and microstructural properties as well as on the device performance of CTS thin films are evaluated. It is found that the properties of CTS thin films are strongly dependent on the Cu Deposition Time during the sputtering process. The Cu Deposition Time is varied from 2812 s to 3212 s, and the film deposited at 2812 s showed the highest power conversion efficiency (PCE) of 2.39% with an open circuit voltage (V oc ) of 208 mV, a short circuit current density (J sc ) of 28.92 mA/cm 2 and a fill factor (FF) of 39.7%.
V. J. Fulari - One of the best experts on this subject based on the ideXlab platform.
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Galvanostatic synthesis of MnCo_2O_4 nanoflakes like thin films: effect of Deposition parameter on supercapacitive performance
Ionics, 2021Co-Authors: Nagesh Maile, S. K. Shinde, A. V. Fulari, D. S. Lee, V. J. FulariAbstract:Different nanostructures of active material have an imperative impact on its supercapacitive performance. Here, the nanoflakes like MnCo_2O_4 thin films have been synthesized by electrochemical method in constant current mode. By varying Deposition parameters such as current density and Deposition Time, structural evolution has been studied. Formation of spinel MnCo_2O_4 has been confirmed by XRD, FT-RAMAN, XPS and EDS analysis. Electrochemical studies suggested that the change in Deposition parameters has an evident effect on the supercapacitive performance of MnCo_2O_4. The optimized current density of − 0.8 mA cm^−2 and the Deposition Time of 40 min evaluated nanoflakes like MnCo_2O_4 thin films, exhibiting a maximum specific capacitance of 52.6 F g^−1.
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effect of different electrolytes and Deposition Time on the supercapacitor properties of nanoflake like co oh 2 electrodes
Ultrasonics Sonochemistry, 2019Co-Authors: N C Maile, A. V. Fulari, Surendra Shinde, R R Koli, D Y Kim, V. J. FulariAbstract:Abstract The effect of ultrasonic treatment and Deposition Time on nanoflake-like Co(OH)2 thin films were prepared using the potentiostatic mode of electroDeposition method on stainless steel substrates by a nitrate reduction reaction. After ultrasonic treatment, we used stainless steel substrates for Deposition of the nanoflakes like Co(OH)2 thin films. The effect of Deposition Times and electrolytes on different physico-chemical properties of Co(OH)2 was investigated in detail, such as X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), and electrochemical testing. After ultrasonic treatment Co(OH)2 thin films had devolvement of the uniform and interconnected formation of nanoflakes nanostructures. Supercapacitor performance of the Co(OH)2 electrodes suggest that, specific capacitance are depends on the surface morphology, and Co(OH)2 electrodes after ultrasonic treatment exhibited higher performance than without ultrasonication. The maximum specific capacitance of the 30 min. deposited Co(OH)2 nanoflakes exceeded 276 Fg−1 in 0.5M KOH electrolyte at 5 mVs−1 scan rate.
