共查询到20条相似文献,搜索用时 15 毫秒
1.
Nari N. Talaty Kristina Beck Helene Citeau Kristin Kirschbaum Dean M. Giolando Prof. Dr. 《无机化学与普通化学杂志》2009,635(1):53-63
A new single‐source precursor, [SnCl4{OC(H)OC2H5}2], prepared by treating tin tetrachloride with ethyl formate (1:2 ratio) was developed for the deposition of tin oxide thin films on glass substrates. The compound [SnCl4{OC(H)OC2H5}2] is highly volatile and provides very high growth rates (up to 100Å s?1 at 560 °C) in an atmospheric pressure chemical vapor deposition (APCVD) reactor. More significantly, the compound does not decompose to tin oxide below 320 °C, thereby minimizing the formation of particles in the vapor above the growing tin oxide film. To prepare highly conducting fluorine doped tin oxide (SnO2:F) films 2,2,2‐trifluoroethyl trifluoroacetate was used as the source of fluoride. High quality SnO2:F films were deposited at 560 °C with a flow rate of 2 mL fluoride reagent hr?1; typical film properties are resistivity of 5.9 X 10?4 Ω cm, Hall mobility of 27.3 cm2 V?1 s?1, carrier concentration of 3.9 X 1020 cm?3 and percent transmission ranging from 86 to 88 %. The best films of SnO2:F possess transparencies as high as 90 % (750 nm), sheet resistances as low as 7 Ω sq?1 and Haacke's figure of merit as high as 29 X 10?3 (750 nm). The newly developed APCVD reactor and the chemistry were optimized with respect to structural, electrical and optical properties of the films by adjusting the substrate temperature, gas flow rates and the amount of fluoride present in the vapor stream. Growth rates with respect to deposition time, substrate temperature and flow rates of precursors were found to be similar for both undoped (SnO2) and doped (SnO2:F) samples. The SnO2:F films possess larger grains than the SnO2 which may account for the lower resistivity and the higher mobility in the SnO2:F samples. 相似文献
2.
C. J. Diliegros-Godines R. Castanedo-Pérez G. Torres-Delgado O. Zelaya-Ángel 《Journal of Sol-Gel Science and Technology》2014,70(3):500-505
Transparent and conducting tin doped cadmium oxide thin films were obtained by mixing cadmium oxide and tin oxide precursor solutions by the sol–gel method. Different tin contents in solution were studied: 0, 0.5, 1, 2, 3, 5 and 10 at.%. The films were sintered at 550 °C and, after that, annealed in N2/H2 gas mixture, in order to decrease their resistivity. X-ray diffraction patterns showed that doping of tin diminishes the [111] light preferred orientation of films and provokes a decrease of the average crystallite size from 30 to 12 nm. Atomic force microscopy images revealed morphological changes with the addition of tin content. All the films showed a high transmission around 75 % in the 600 < λ < 1,700 nm range and a shift of the absorption edge towards the blue region as the tin concentration was increased. The cadmium oxide films doped with 1 at.% of tin showed the lowest resistivity of 5.7 × 10?4 Ω cm and a band gap energy value of 2.7 eV. For their characteristics, these CdO:Sn films are good candidates as transparent conductive electrodes in CdS/CdTe and CdS/CIGS type solar cells. 相似文献
3.
Electrical conducitivities of both ferricytochrome c and ferrocytochrome c anhydrous films were measured at physiological temperatures. A film-casting method was applied to prepare the films. Rather low values of resistivities (55°C) of 6.5 × 1010 Ω cm for ferrocytochrome c in comparison with the previously reported value of 1011 Ω cm (127°C) were obtained. Apparent activation energies for the above conductivities, 0.6 eV, were the same in both samples. 相似文献
4.
Siu‐Ming Yuen Chen‐Chi M. Ma Chin‐Lung Chiang Yao‐Yu Lin Chih‐Chun Teng 《Journal of polymer science. Part A, Polymer chemistry》2007,45(15):3349-3358
Precursor of polyimide, polyamic acid has been prepared sucessfully. Acid‐modified carbon nanotube (MWCNT) was grafted with soluble polyimide then was added to the polyamic acid and heated to 300 °C to form polyimide/carbon nanotube composite via imidation. Morphology, mechanical properties and electrical resistivity of the MWCNT/polyimide composites have been studied. Transmission electron microscope microphotographs show that the diameter of soluble polyimide‐grafted MWCNT was increased from 30–60 nm to 200 nm, that is a thickness of 70–85 nm of the soluble polyimide was grafted on the MWCNT surface. PI‐g‐MWCNT was well dispersed in the polymer matrix. Percolation threshold of MWCNT/polyimide composites has been investigated. PI‐g‐MWCNT/PI composites exhibit lower electrical resistivity than that of the acid‐modified MWCNT/PI composites. The surface resistivity of 5.0 phr MWCNT/polyimide composites was 2.82 × 108 Ω/cm2 (PI‐g‐MWCNT) and 2.53 × 109 Ω/cm2 (acid‐modified MWCNT). The volume resistivity of 5.0 phr MWCNT/polyimide composites was 8.77 × 106 Ω cm (PI‐g‐MWCNT) and 1.33 × 1013 Ω cm (acid‐modified MWCNT).Tensile strength and Young's modulus increased significantly with the increase of MWCNT content. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3349–3358, 2007 相似文献
5.
Yanwei Huang Dezeng Li Jiahan Feng Guifeng Li Qun Zhang 《Journal of Sol-Gel Science and Technology》2010,54(3):276-281
Transparent conductive tungsten-doped tin oxide (SnO2:W) thin films were synthesized on quartz glass substrates by sol–gel dip-coating method. It was found that the films were highly transparent and the average optical transmission was about 90% in the visible and near infrared region from 400 to 2,500 nm. The optical band gap is about 4.1 eV. The lowest resistivity of 5.8 × 10?3 ohm cm was obtained, with the carrier mobility of 14.2 cm2 V?1 s?1 and carrier concentration of 7.6 × 1019 cm?3 in 3 at.% W-doping films annealed at 850 °C in air. The structural properties, surface morphology and chemical states for the films were investigated. 相似文献
6.
《Solid State Sciences》2012,14(6):705-710
Transparent conducting undoped and tin doped ZnO multilayer films were deposited by sol-gel method. Effect of open air annealing on different parameters like grain size, carrier density, band gap, resistivity, refractive index and extinction coefficient were investigated. Films were deposited on glass and silicon substrate by keeping doping concentration 4 at%. It was observed that tin doping reduces resistivity from 194.6 Ω cm to 3.11 Ω cm. Optical transmission spectra exhibit transmittance above 88% in visible range. Maximum carrier density of 11.9 × 1018 cm−3 and band gap of 3.24 eV was estimated at 375 °C. Scanning Electron Microscopy showed homogenous worm like morphology. Atomic force microscopy revealed pyramid shaped nanostructure of tin doped ZnO. 相似文献
7.
《高分子科学杂志,A辑:纯化学与应用化学》2013,50(9):933-944
A new class of polyethers has been prepared by the Mitsunobu coupling of poly(4-vinyl phenol), P4VP, with low molecular weight poly(ethylene glycol)methyl ether. These comb-like polymers, having ca. 20–30% residual phenols, were characterized by IR, DSC, and TGA. Results of thermal analysis on the polymers suggest thermal stability to at least 300°C and a glass transition temperature in the range ?30 to ?40°C. Complexes with LiPF6 gave conductivities of ca. 1 × 10?5 S/cm at room temperature. The polymers were blended with plasticized poly(vinylidene fluoride) (PVDF) to prepare porous films and subsequently infiltrated with lithium salts and ethylene and ethyl methyl carbonate. Ionic conductivities of these hybrid films were measured from ?20°C to 40°C. Conductivities as high as 2.4 × 10?3 S/cm are observed at room temperature. The electrochemical stability of hybrid materials was studied by cyclic voltammetry. 相似文献
8.
采用旋涂法用浓度分别为0.05,0.10和0.25 mol·L-1的氧化锌前躯体溶液制备了氧化锌薄膜,并且制备了基于氧化锌多层膜的顶栅极晶体管器件,其中以利用光刻工艺刻蚀的氧化铟锡为源漏电极。通过原子力显微镜(AFM)和X-射线衍射(XRD)分别表征了薄膜的形貌以及结晶情况,并且讨论了前躯体的浓度顺序对氧化锌多层膜的影响。按照浓度从大到小的顺序依次旋涂前躯体溶液制备的氧化锌薄膜表现出了较高的载流子迁移率(7.1×10-3 cm2·V-1·s-1),而按照浓度从小到大的顺序依次旋涂前躯体溶液制备的氧化锌薄膜的载流子迁移率为5.2×10-3 cm2·V-1·s-1。文中通过对两种多层薄膜的形貌和结晶性能的分析表明影响顶栅极薄膜晶体管性能的主要因素是薄膜的粗糙度。平整的薄膜有利于形成较好的半导体层/绝缘层接触界面,从而有利于提高器件的载流子迁移率。 相似文献
9.
Poly(p-phenylene biphenyltetracarboximide) films with various thicknesses were prepared from the poly(amic acid) precursor by thermal imidization at 230–400°C for 1–10 h under a nitrogen atmosphere. The water sorption in the films was measured at 25°C over 22–100% relative humidity using a Cahn microbalance as a function of film thickness and thermal imidization history. The water diffusion in all the films followed nearly Fickian process despite the morphological heterogeneity due to the ordered and less ordered phases. The diffusion coefficient and water uptake varied in 0.85 × 10?10 ? 7.50 × 10?10 cm2/s and 0.12–2.4 wt %, respectively, depending upon humidity, film thickness, and imidization history. Both diffusion coefficient and water uptake increased with increasing humidity, but decreased as imidization temperature and time increased. With increasing film thickness, the diffusion coefficient increased whereas the water uptake decreased. The water sorption behavior was interpreted with the consideration of morphological variations, such as polymer chain order, in-plane orientation, and intermolecular packing order due to the film thickness and imidization history. © 1995 John Wiley & Sons, Inc. 相似文献
10.
Liang Zhao Xiaoru Zhao Jinming Liu An Zhang Danhong Wang Bingbo Wei 《Journal of Sol-Gel Science and Technology》2010,53(2):475-479
Anatase Ti0.94Nb0.06O2 (TNO) films were fabricated on glass substrates by sol–gel method using a dip-coating technique. The annealing treatment
was separated into two steps, first in air at 350–550 °C for 1 h and then in vacuum of 4.0 × 10−4 Pa at 550 °C for 1 h. The influence of vacuum annealing treatment to the electrical and optical properties was discussed.
Especially, the role of air annealing treatment from 350 to 550 °C on the crystallization and the structure of the films was
analyzed. It is proved that the films annealed at 550 °C in air and then 550 °C in vacuum exhibited the minimum resistivity
of 19.3 Ω·cm and the average optical transmittance of about 75% in the visible range, indicating that the sol–gel method is a feasible
and promising method to fabricate TNO films. 相似文献
11.
Thermo‐stable 2‐(arylimino)benzylidene‐9‐arylimino‐5,6,7,8‐tetrahydro cyclohepta[b]pyridyliron(II) precatalysts toward ethylene polymerization and highly linear polyethylenes
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Fang Huang Tongling Liang Xinquan Hu Wen‐Hua Sun 《Journal of polymer science. Part A, Polymer chemistry》2017,55(5):830-842
A series of 2‐(arylimino)benzylidene‐9‐arylimino‐5,6,7,8‐tetrahydrocyclohepta[b] pyridyliron(II) chlorides was synthesized and characterized using FT‐IR and elemental analysis, and the molecular structures of complexes Fe3 and Fe4 have been confirmed by the single‐crystal X‐ray diffraction as a pseudo‐square‐pyramidal or distorted trigonal‐bipyramidal geometry around the iron core. On activation with methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all iron precatalysts exhibited high activities toward ethylene polymerization with a marvelous thermo‐stability and long lifetime. The Fe4 /MAO system showed highest activity of 1.56 × 107 gPE·mol?1(Fe)·h?1 at 70 °C, which is one of the highest activities toward ethylene polymerization by iron precatalysts. Even up to 80 °C, Fe3 /MAO system still persist high activity as 6.87 × 106 g(PE)·mol?1(Fe)·h?1, demonstrating remarkable thermal stability for industrial polymerizations (80–100 °C). This was mainly attributing to the phenyl modification of the framework of the iron precatalysts. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 830–842 相似文献
12.
Masahiro Teraguchi Toshio Masuda 《Journal of polymer science. Part A, Polymer chemistry》1999,37(24):4546-4553
Three disubstituted acetylenes with an adamantyl group—1-(p-adamantylphenyl)-2-chloroacetylene (ClpAdPA), 1-(p-adamantylphenyl)-1-propyne (pAdPP), and 1-(p-adamantylphenyl)-2-phenylacetylene (pAdDPA)—polymerized in good yields in the presence of MoCl5- or TaCl5-based catalysts. The highest weight-average molecular weights of poly(ClpAdPA), poly(pAdPP), and poly(pAdDPA) reached 3.6 × 105, 1.1 × 106, and 6.0 × 106, respectively. The polymers were yellow to white solids and completely soluble in toluene, chloroform, and so forth. These polymers thermally were fairly stable, and the onset temperatures of weight loss in air were over 360 °C. Poly(pAdPP) and poly(pAdDPA) provided free-standing films by solution casting, and their oxygen permeability coefficients (PO2) at 25 °C were 8.6 and 55 barrers [1 barrer = 1 × 10−10 cm3 · (STP) · cm/(cm2 · s · cm Hg)], respectively, which are relatively small compared to those of other substituted polyacetylenes. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4546–4553, 1999 相似文献
13.
Zhi Ma Hang Wang Jiaoming Qiu Demin Xu Youliang Hu 《Macromolecular rapid communications》2001,22(15):1280-1283
A novel highly active catalyst 2,6‐bis[1‐(2‐methylnaphthylimino)ethyl]pyridineiron(II) chloride ( 1 ) is reported for ethylene polymerization. Compared with 2,6‐bis[(1‐naphthylimino)ethyl]pyridineiron(II) chloride ( 2 ) reported recently, catalytic activities of this new complex are high with maximum activity 6.51×106 g PE·mol–1·Fe·h–1·bar–1 at 40°C. The activity of the catalyst, and the molecular weight and melting temperature of the polymers depend on the methylaluminoxane/ 1 molar ratio and polymerization temperature. 相似文献
14.
This paper presents measurements of the ionic conductivity in single crystals of β″-alumina (0.84 M2O · 0.67 MgO · 5.2 Al2O3, M = Na, K, Ag). Single crystals of sodium β″-alumina were grown from a melt of Na2O, MgO, and Al2O3 at 1660 to 1730°C. Selected crystals were converted to the other isomorphs by ion exchange. The conductivity of sodium β″-alumina varies from 0.18 to 0.01 (ohm · cm)?1 at 25°C depending upon crystal growth conditions. Potassium β″-alumina has the unusually high room temperature conductivity of 0.13 (ohm · cm)?1. Silver β″-alumina has a slightly lower conductivity, 4 × 10?3 (ohm · cm)?1 at 25°C. The activation energies of sodium and potassium β″-alumina decrease with increasing temperature, while that of silver β″-alumina is constant from ?80 to 450°C. 相似文献
15.
Juan Peng Chenhang Sheng Jifeng Shi Xifeng Li Jianhua Zhang 《Journal of Sol-Gel Science and Technology》2014,71(3):458-463
In this paper, high-k titanium–aluminum oxide (ATO) dielectric film has been realized by using organic–inorganic hybrid precursor solution. X-ray diffraction pattern revealed that the ATO films (Ti content less than 67 at%) remain amorphous phase for annealing treatment at 400 °C. And all of the amorphous ATO films had very smooth and uniform surface with root mean square (RMS) roughness of less than 0.5 nm. Meanwhile, the results showed that the ATO film (Ti:Al = 1:8) had the best performance, including RMS roughness of 0.33 nm, relative permittivity of 15, and leakage current density of 1.41 × 10?6 A/cm2 at 1 MV/cm. 相似文献
16.
Li Gang Zhu Xuebin Lei Hechang Jiang Haifeng Song Wenhai Yang Zhaorong Dai Jianming Sun Yuping Pan Xu Dai Songyuan 《Journal of Sol-Gel Science and Technology》2010,53(3):641-646
CuAlO2 thin films were prepared on quartz glass and sapphire substrates by chemical solution deposition method using copper acetate
monohydrate, aluminum nitrate nonahydrate and 2-methoxyethanol as starting precursor and solvent. The effects of annealing
temperature on the structural, morphological, electrical and optical properties have been studied. Via the optimized annealing
treatment condition, CuAlO2 film annealed at 850 °C in nitrogen flow of 400sccm under atmosphere pressure exhibits the best performance with the lowest
room temperature resistivity of 3.6 × 102 Ω cm and the highest optical transmission in the visible region (>70% at around 600 nm wavelength). CuAl2O4 and CuO phases, not CuAlO2 phase are obtained when annealing temperature is lower than 850 °C. However, a further increase of annealing temperature
weakens the crystallization quality and deteriorates the surface morphology of CuAlO2 films as the annealing temperature exceeds 850 °C, leading to an increase in the resistivity and a decrease of the optical
transmission in the visible region of CuAlO2 films. 相似文献
17.
The mass transport and charge transfer kinetics of ozone reduction at Nafion coated Au electrodes were studied in 0.5 mol/L H2SO4 and highly resistive solutions such as distilled water and tap water. The diffusion coefficient and partition coefficient of ozone in Nafion coating are 1.78×10-6 cm2·s-1 and 2.75 at 25℃ (based on dry state thickness), respectively. The heterogeneous rate constants and Tafel slopes for ozone reduction at bare Au are 4.1×10-6 cm·s-1, 1.0×10-6 cm·s-1 and 181 mV, 207 mV in 0.5 mol/L H2SO4 and distilled water respectively and the corresponding values for Nafion coated Au are 5.5×10-6 cm·s-1, 1.1×10-6 cm·s-1 and 182 mV, 168 mV respectively. The Au microelectrode with 3 μm Nafion coating shows good linearity over the range 0-10 mmol/L ozone in distilled water with sensitivity 61 μA·ppm-1 ·cm-2, detection limit 10 ppb and 95% response time below 5 s at 25℃. The temperature coefficient in range of 11-30℃ is 1.3%. 相似文献
18.
Time-consuming fusion and pyrohydrolysis methods for quantifying fluoride and tin in fluoride-doped tin oxide films on glass are replaced by a simple electrolytic reduction for sample preparation. The unusual conductivity of these films enables solutions to be produced in which fluoride can be quantified by ion chromatography. Tin is quantified in the original sample by x-ray fluorescence spectrometry. Electrolytic reduction and the fusion/pyrohydrolysis methods are compared for films with Sn/F ratios of 10–40 (71–183 μg cm?2 tin and 0.54–2.8 μ cm?2 fluoride). The Sn/F ratios and precision are similar for the two methods. The older method only yields the tin/fluoride ratio; the electrolytic method gives results as mass per unit area and requires much less time per sample. 相似文献
19.
H. M. Tong K. L. Saenger C. J. Durning 《Journal of Polymer Science.Polymer Physics》1989,27(3):689-708
Using laser interferometry, we have determined in situ the thickness increase with time of thin supported polyimide films (4–8 μm in initial thickness) immersed in n-methyl-2-pyrrolidone (NMP) as a function of NMP temperature (22–120°C). Similar experiments were also performed in dimethyl sulfoxide (DMSO) at 22°C with polyimide films of 4.1 μm in thickness. For NMP, the equilibrium fractional thickness increase (about 20%) is independent of initial polyimide thickness and temperature. The time scale for reaching equilibrium sharply decreases with temperature from 2–3 days at 22°C to 30–60 min at 120°C. Compared with NMP, the rate of DMSO sorption is considerably faster, reaching equilibrium swelling of about 28% in about 5 h at 22°C. To describe the transport process, we applied a phenomenological model proposed by Astarita and Sarti1 but reformulated in polymer fixed frame to enable straightforward comparison with the thickness data. Our analysis indicated that the transport of NMP is best described as anomalous, that is, intermediate between diffusion controlled and case II transport. The effective diffusion coefficient Deff and the front velocity U0 at 22°C were found to be 3–6 × 10?12 cm2/s and 8 × 10?9 cm/s, respectively. Our front velocity is in good accord with the value of 6 × 10?9 cm/s obtained for a similar polyimide based on gravimetric measurements.2 Both Deff and U0 show an activation energy of ~56 kJ/mol. For DMSO, however, the transport is clearly case II. The front velocity at 22°C was found to be about 6 × 10?8 cm/s, which is about four times that obtained by Rutherford back-scattering spectrometry.3 相似文献
20.
Ying Li Gaoyang Zhao Yang Ren Dichun Chen 《Surface and interface analysis : SIA》2011,43(9):1199-1202
The technique for ITO (Tin‐doped indium oxide) thin films by sol‐gel process is presented in this paper. After annealing at 500° for 15 min, ITO gel films get transformed into nanocrystallined indium tin oxide films. We studied the microstructure of ITO thin film which is closely related to optical and electrical properties. The microstructure of ITO thin film can be observed through high‐resolution transmission electronic spectroscopy (HRTEM) and the Fast Fourier Transform (FFT) technique. The film is nanocrystallite with grain sizes about 20 nm. Also, the surface chemical components were studied by XPS spectra. The transmission and the resistivity of ITO films is 97.0% and 3.5 × 10?3 Ω?cm, respectively. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献