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1.
Highly ordered TiO2 nanotube arrays (TNAs) fabricated by anodization are very attractive for use in dye-sensitized solar cells (DSSCs), because of their superior charge percolation and slow charge recombination. Highly ordered, vertically aligned TNAs have been prepared by three-step anodic oxidation. In this work, we investigated such strategies for improving the efficiency of DSSCs. Based on one of these approaches, oxide semiconductors in the form of a TNA were used as a novel method for improving electron transport through a film. A solution containing an appropriate amount of TiO2 nanoparticles was prepared, and the mixed slurry was spin-coated on a TNA film. The coated film provided a large surface area for dye adsorption. The DSSCs achieved a light-to-electric energy conversion efficiency of 5.91% under simulated solar irradiation at 100 mW/cm2 (AM 1.5).  相似文献   

2.
Abstract

The aim of this research is to investigate the photodegradation of Methylene Blue with Fe3O4/ZnO core-shells. Fe3O4/ZnO core-shells were synthesized by a simple two-step chemical method (co-precipitation and precipitation) using a molar variation of Zn-acetate precursor. We found that the presence of Fe2O3 plays an important role in enhancement of photocatalytic activity due to the existence of higher concentration of surface oxygen vacancies and the suppressing effect of the Fe2+ ions on the recombination of photoinduced electron-hole pairs. The core-shell photocatalyst can be easily separated by using a commercial magnet without reduces photocatalytic efficiency within three times of recycling process.  相似文献   

3.
The photvoltaic performance of polymer solar cell (PSC) with a three-component active layer was studied. The incorporation of 4-cyano-4’-octylbiphenyl (8CB) as an additive to a P3HT [poly(3-hexylthiophene)]:PC61BM [[6,6]-phenyl-C61-butyric acid methyl ester] blend film led to a higher absorbance, larger crystal size, closer packing of P3HT, and hence enhanced hole mobility. The power conversion efficiency of the PSC with the three-component active layer (P3HT: PC61BM:8CB blend film) was improved by over 30% compared to that of the reference device without 8CB, due to an enhancement in all parameters such as short circuit current, open circuit voltage and fill factor.  相似文献   

4.
ABSTRACT

TiO2, ZnO and ZnO/TiO2 thin films have been prepared by radio frequency magnetron sputtering method under different temperatures. Their photo catalytic activities have been investigated. The structural of the thin films were characterized by X-ray diffraction and Raman spectroscopy. The photo catalytic activities of TiO2 and ZnO/TiO2 samples were evaluated by the photo decomposition of methylene blue. We note that the structural proprieties of the thin films showed a perfect crystallization along the (002) for ZnO, Rutile (110) for TiO2 and Anatase (101) for TiO2. The experimental results show that the bilayer ZnO/TiO2 were the most efficient photo catalysts compared to the layer of TiO2. This increased catalytic effect can attributed to the interface between the ZnO layer and the TiO2 one, which modify significantly the chemical potential of the bilayer.  相似文献   

5.
The Fe2O3/Ag core-shell composite nanoparticles were successfully prepared via a simple method at low temperature. X-ray diffraction data revealed the formation of core-shell composite nanoparticles, with Fe2O3 as the core and silver as the shell. The results from the transmission electron microscopy and scan electron microscopy further indicated that the composite nanoparticles were spherical with a core diameter and shell thickness of 26.0 nm and 13.5 nm, respectively. Magnetic measurements showed that the composite nanoparticles exhibited a typical ferromagnetic behavior, a specific saturation magnetization of 0.95 emu/g and an intrinsic coercivity of 104.0 Oe at room temperature. For a standard two-probe analysis at room temperature, the composite nanoparticles showed a typical conductive behavior and its conductivity was about 3.41 S/m. Moreover, this present synthesis method of Fe2O3/Ag core-shell composite nanoparticles shows an easy processing and does not need high-temperature calcining to attain the final product, which can be applied in a variety of areas, including catalysis, medicine, photonics, and new functional device assemblies.  相似文献   

6.
Abstract

TiO2 intercalated H4Nb6O17 has been synthesized by the reactions of H4Nb6O17 with a titanyl acylate complex followed by UV irradiation. The gallery height, specific surface area and Ti content of the sample synthesized by using titanyl acylate complex were larger than that using TiO2 sol solution. Furthermore, the photocatalytic activity of the TiO2 pillared H4Nb6O17 prepared using a titanyl acylate precursor was twice larger than that fabricated using a TiO2 sol solution.  相似文献   

7.
Syntheses and single-crystal X-ray structural results are reported for three new mixed diphosphates of the family AI 2BII 3(P2O7)2; Ag2Co3(P2O7)2 (I), Ag2Mn3(P2O7)2 (II), and Na2Cd3(P2O7)2 (III). All crystallize in the triclinic system, space group P1 bar: (I) a = 5.351(4), b = 6.375(4), c = 16.532(4) Å, = 80.83(6) = 81.45(4), = 72.87(5)°, V = 528.9(6) Å3, Z = 2, D calc = 4.649 mg/m3, R/Rw = 0.0428/0.0548 for 3949 obs. reflns; (II) a = 5.432(7), b = 6.619(6), c = 16.51(3) Å, = 80.78(8) = 82.43(9), = 72.82(7)°, V = 557.7(13) Å3, Z = 2, D calc = 4.338 mg/m3, R/Rw = 0.0679/0.1303 for 2100 obs. reflns and (III) a = 5.67(3), b = 7.08(4), c = 7.90(4) Å, = 77.0(2), = 82.5(2), = 67.8(2)°, V = 286(3) Å3, Z = 2, D calc = 4.249 mg/m3, R/Rw = 0.0307/0.0342 for 1945 obs. reflns. (I) and (II) are isostructural but (III) is of a different type. All three structures are characterized by layers of P2O7 groups alternating with layers of mixed metal atoms. Differences are seen in the conglomerate bonding patterns of B atoms and in the irregular geometry of Ag in (I) and (II) compared to the octahedral bonding seen for Na in (III). The differences in structure may be understood in terms of the ratios of the ionic radii of A and B atoms.  相似文献   

8.
陈阔  李长久  贾阳  俞琳  姜宏 《人工晶体学报》2016,45(12):2778-2784
采用高温熔融法和两步法微晶热处理制备了MgO-Al2O3-SiO2系堇青石微晶玻璃和铁尖晶石微晶玻璃.利用DSC分析、X射线衍射、FTIR和扫描电子显微镜等手段研究了Fe2O3对玻璃的析晶性能、显微结构和物理性能的影响.结果表明,Fe2 O3的加入可有效降低析晶活化能,促进晶体的析出.当Fe2O3含量达到7.44;时,主晶相由堇青石变为铁尖晶石.Fe2O3掺杂使样品的介电常数由3.2增大至5.8、热膨胀系数由1.941× 10-7增大至7.74×10-6、维氏硬度由7.131GPa增大至11.655 GPa,同时介电损耗由0.05降低至0.015.  相似文献   

9.
Abstract

Electrical conductivity and thermoelectric power measurements (77–300K) of both the pure and electrochemically doped with lithium Bi2Sr2CaCu2O8 system, are presented. Clear correlation between transport and electrochemical properties of LixBi2Sr2CaCu2O8 was shown.  相似文献   

10.
ABSTRACT

TiO2:SnO2 thin films were deposited on glass substrates, by using sol gel spin coating method with different ratio (3%, 5% and 7%) at 3200 rpm, to study their effect on different properties of TiO2: SnO2 thin films. The structural and optical properties of films have studied for different ratio. These deposited films have been characterized by various methods such as X-Ray Diffraction (XRD), Ultra Visible spectroscopy. The (XRD) can be used to identify crystal structure of as deposited films. The Transmission spectra have shown the transparent and opaque parts in the visible and UV wavelengths.  相似文献   

11.
N. Baizura 《Journal of Non》2011,357(15):2810-2815
Tellurite 75TeO2-(10 − x)Nb2O5-15ZnO-(x)Er2O3; (x = 0.0-2.5 mol%) glass system with concurrent reduction of Nb2O5 and Er2O3 addition have been prepared by melt-quenching method. Elastic properties together with structural properties of the glasses were investigated by measuring both longitudinal and shear velocities using the pulse-echo-overlap technique at 5 MHz and Fourier Transform Infrared (FTIR) spectroscopy, respectively. Shear velocity, shear modulus, Young's modulus and Debye temperature were observed to initially decrease at x = 0.5 mol% but remained constant between x = 1.0 mol% to x = 2.0 mol%, before increasing back with Er2O3 addition at x = 2.5 mol%. The initial drop in shear velocity and related elastic moduli observed at x = 0.5 mol% were suggested to be due to weakening of glass network rigidity as a result of increase in non-bridging oxygen (NBO) ions as a consequence of Nb2O5 reduction. The near constant values of shear velocity, elastic moduli, Debye temperature, hardness and Poisson's ratio between x = 0.5 mol% to x = 2.0 mol% were suggested to be due to competition between bridging oxygen (BO) and NBO ions in the glass network as Er2O3 gradually compensated for Nb2O5. Further addition of Er2O3 (x > 2.0 mol%) seems to further reduce NBO leading to improved rigidity of the glass network causing a large increase of ultrasonic velocity (vL and vS) and related elastic moduli at x = 2.5 mol%. FTIR analysis on NbO6 octahedral, TeO4 trigonal bipyramid (tbp) and TeO3 trigonal pyramid (tp) absorption peaks confirmed the initial formation of NBO ions at x = 0.5 mol% followed by NBO/BO competition at x = 0.5-2.0 mol%. Appearance of ZnO4 tetrahedra and increase in intensity of TeO4 tbp absorption peaks at x = 2.0 mol% and x = 2.5 mol% indicate increase in formation of BO.  相似文献   

12.
Abstract  [Na(H2O)2(C18H15O6SO3)]2 was synthesized by sulfated 5-hydroxy-6,7,4′-trimethoxyisoflavone with concentrated sulfuric acid. Single-crystal X-ray diffraction study indicates that it is a dimeric centrosymmetric species. The coordination polyhedron of each Na(I) atom exhibits a distorted trigonal bipyramidal geometry. The dimeric units are linked by intermolecular hydrogen bonds C–H⋯π, C–H⋯O and O–H⋯O to result in a three-dimensional framework. Graphical Abstract  [Na(H2O)2(C18H15O6SO3)]2 was synthesized by sulfated 5-hydroxy-6,7,4′-trimethoxyisoflavone with concentrated sulfuric acid. The coordination polyhedron of each Na(I) atom exhibits a distorted trigonal bipyramidal geometry. The dimeric centrosymmetric units are linked by intermolecular hydrogen bonds C–H⋯π, C–H⋯O and O–H⋯O to result in a three-dimensional framework. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

13.
为改善CuCr2O4黑色颜料呈色性能,将Fe3+掺杂进入CuCr2O4晶体中,采用共沉淀法制备CuCr2-xFexO4(x=0,0.04,0.05,0.06,0.07),并对所制备样品进行TG-DTA、XRD、SEM、Raman、XPS、UV-Vis吸收光谱和色度值的测试与表征.结果表明,Fe以三价态固溶进入Cr3+位...  相似文献   

14.
ABSTRACT

In the present work, to build a water splitting system using only a neutral electrolyte solution and light source, we investigated the photoelectrochemical properties and interface resistances of an IrO2-coated TiO2 photoanode in Z-scheme configuration. The photoelectrochemical cell was connected to the perovskite solar cell with to realize the system with no need for an external electrical bias. Photoanodes with IrO2 were found to support hole transport and to reduce the overpotential, therefore increasing the current density of the system consisting of photoelectrochemical cells. A maximum solar-to-hydrogen efficiency of 8.2% was achieved in a neutral electrolyte.  相似文献   

15.
Min Wang  Jiao Jin  Jiwei Zhai 《Journal of Non》2011,357(3):1160-1163
A sol-gel method was used to prepare CaO-B2O3-SiO2 (CBS) glass powder for making low-temperature cofired ceramics. This paper was focused on the mechanism of hydrolysis and polymerization and also on the structural evolution of xerogel at various temperatures. The xerogel was transformed into glass ceramics containing CaSiO3 and CaB2O4 crystalline phases through nucleation and crystallization processes. The results indicated that the xerogel exhibits [BO4] or [SiO4] based three-dimensional network structure whose interstices Ca ions fill in, which becomes more orderly and stable after heat treatments. The CBS glass ceramics through controlled crystallization have a potential as electronic packaging materials.  相似文献   

16.
An important question in the manufacture of superconducting electronics is how to control the two-level systems found in amorphous insulators. The present article shows that hydrogen has a marked impact on the two-level systems in thin films of reactively sputtered Al2O3, a standard tunnel oxide for Josephson junctions. The magnitude of dielectric relaxation current in Al2O3 films, believed to be caused by two-level systems, is shown to increase monotonically with the flow rate of H2 into the chamber during deposition. This points toward a potential need for controlling hydrogen during the manufacture of superconducting electronics utilizing Al2O3.  相似文献   

17.
Abstract

In this work we prepared the stable photocatalyst by the incorporation of lithium into TiO2 host. Lithium hydroxide was used as the modifier. Titanium host material was in two forms: commercial titanium dioxide (anatase. Police Chemical Factory, Poland) and titanium slurry that was slightly crystallized. The prepared materials have been characterized by XRD. FTIR and UV-Vis/DR methods. The XRD analysis showed that the main component of these samples was lithium titanate—Li2TiO3. The photocatalytic activity of prepared materials was tested in the photocatalytic reactions of oil and phenol decomposition in water. It was found that both oil and phenol undergo the photocatalytic decomposition over lithium-TiO2 and the activity of these materials was higher in comparison with that of pure anatase host.  相似文献   

18.
Polydimethylsiloxane (PDMS)-based organic-inorganic hybrids have been studied because of their high dielectric strength, heat resistivity, and flexibility. In this study, we fabricated Al2O3 coatings on metal substrates with sufficient electrical insulation, heat conductivity, and thermal stability by electrophoretic deposition (EPD) using PDMS-based hybrid binders. The scratch hardness, thermal conductivity, and electrical breakdown strength of the Al2O3 coating before and after heat treatment at 300 °C for 500 h were 2.0 N, 3.1 W/mK, and 60 kV/mm, respectively. These results demonstrate the usefulness of EPD using PDMS-based hybrid binders for fabricating flexible heat dissipative substrates used in high-temperature environments.  相似文献   

19.
ABSTRACT

The slow rate of the oxygen reduction reaction (ORR) and the instability of Pt based catalysts are two of the most important issues which must be solved in order to make proton exchange membrane fuel cells (PEMFCs) a reality. Here, we present a new approach by exploring robust non-carbon Ti0.7In0.3O2 used as a novel functionalised co-catalytic support for Pt. This approach is based on the novel nanostructure Ti0.7In0.3O2 support with “electronic transfer mechanism” from Ti0.7In0.3O2 to Pt that can modify surface electronic structure of Pt, owing to a shift in the d-band centre of the surface Pt atoms. The 20 wt% Pt/Ti0.7In0.3O2 catalyst shows high activity than that of that of the commercial 20 wt% Pt/C (E-TEK). Our data suggest this enhancement is a result of both the electronic structure change of Pt upon its synergistic interaction with Ti0.7In0.3O2 and the inherent structural and chemical stability and the corrosion-resistance of the Ti0.7In0.3O2 in acidic and oxidative environments.  相似文献   

20.
The pseudo-binary NdBa2Cu3Ox–Ba3Cu10O13 phase diagrams and the crystallization of NdBa2Cu3Ox have been in situ observed using high-temperature optical microscope under three different oxygen atmospheres namely 1%, 0.1% and 0.0097% oxygen in argon. It has been observed that the liquidus line becomes narrower both in composition and temperature with decreasing oxygen pressure. This result suggested that under reduced oxygen atmosphere, the NdBa2Cu3Ox crystals could only be grown from a peritectic melt consisting of Nd4Ba2Cu2O10 and liquid. The crystallization temperature of NdBa2Cu3Ox was found to decrease logarithmically with decreasing oxygen content in the atmosphere.  相似文献   

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