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oe1(光电查) - 科学论文

42 条数据
?? 中文(中国)
  • Seed Free Growth of Aligned ZnO Nanowire Arrays on AZO Substrate

    摘要: In the absence of commonly used seed layer, we can still successfully synthesized aligned ZnO nanowire arrays by the hydrothermal method. By using aluminum-doped zinc oxide (AZO) glass as a substrate, high-density and vertically aligned ZnO nanowires were synthesized directly on the substrate in the absence of the ZnO seed layer. The current-voltage curve indicated that the sample grown on AZO glass substrate in the absence of seed layer possesses better conductivity than that synthesized on FTO glass substrate with ZnO seed layer. Thus, a simplified, seed-free and low-cost experimental protocol was reported here for large-scale production of high quality ZnO nanowire arrays with promoted conductivity.

    关键词: conductivity,ZnO nanowire arrays,seed layer free,AZO substrate

    更新于2025-09-23 15:23:52

  • Photostable coumarin containing azo dyes with multifunctional property

    摘要: A series five coumarin azo disperse dyes with thiophene bridge are synthesized using diazotized aniline derivatives which are confirmed by FT-IR, 1H NMR, 13C NMR, and CHN analysis. The dyes are applied on polyester and nylon material. The multifunctional properties (lightfastness, washing fastness, sublimation fastness, K/S, UPF, and antimicrobial activity) of the dyed fabric are determined. The dye 3a (-NO2) show red shifted absorption (649 nm) and blocking 95.5-97.4% of UV radiations with 96% antimicrobial property. The geometries of all the azo dyes are optimized using Density Functional Theory (DFT). The Global Reactivity Descriptors (GRD) are evaluated at the same method of theory. The GRD obtained shows a linear relation with lightfastness and UPF ratings. The antimicrobial activity of all synthesized dyes are determined by AATCC 100 test method and it is correlated with the HOMO-LUMO energy band gap.

    关键词: UPF,fastness property,Coumarin-azo dyes,global reactivity descriptors,HOMO-LUMO gap,antimicrobial activity

    更新于2025-09-23 15:23:52

  • Sequential anaerobic and electro-Fenton processes mediated by W and Mo oxides for degradation/mineralization of azo dye methyl orange in photo assisted microbial fuel cells

    摘要: The intensification of the degradation and mineralization of the azo dye methyl orange (MO) in contaminated water with simultaneous production of renewable electrical energy was achieved in photo-assisted microbial fuel cells (MFCs) operated sequentially under anaerobic - aerobic processes, in the presence of Fe(III) and W and Mo oxides catalytic species. In this novel process, the W and Mo oxides deposited on the graphite felt cathodes accelerated electron transfer and the reductive decolorization of MO. Simultaneously, the mineralization of MO and intermediate products was intensified by the production of hydroxyl radicals (HO?) produced by (i) the photoreduction of Fe(III) to Fe(II), and by (ii) the reaction of the photochemically and electrochemically produced Fe(II) with hydrogen peroxide, which was produced in-situ during the aerobic stage. Under anaerobic conditions, the reductive decolorization of MO was driven by cathodic electrons, while the partial oxidation of the intermediates proceeded through holes oxidation, producing N,N-dimethyl-p-phenylenediamine. In contrast, under aerobic conditions superoxide radicals (O2?-) were predominant to HO?, forming 4-hydroxy-N,N-dimethylaniline. In the presence of Fe(III) and under aerobic conditions, the oxidation of the intermediate products driven by HO? superseded that of O2?-, yielding phenol and amines, via the oxidation of 4-hydroxy-N,N-dimethylaniline and N,N-dimethyl-p-phenylenediamine. These sequential anaerobic and electro-Fenton processes led to the production of benzene and significantly faster oxidation reactions, compared to either the anaerobic or the aerobic operation in the presence of Fe(III). Complete degradation and mineralization (96.8 ± 3.5%) of MO (20 mg/L) with simultaneous electricity production (0.0002 kWh/kg MO) was therefore achieved with sequential anaerobic (20 min) - aerobic (100 min) operation in the presence of Fe(III) (10 mg/L). This study demonstrates an alternative and environmentally benign approach for efficient remediation of azo dye contaminated water with simultaneous production of renewable energy.

    关键词: azo dye,decolorization,photo-assisted microbial fuel cells,electro-Fenton,mineralization

    更新于2025-09-23 15:23:52

  • Highly Conductive and Transparent AZO Films Fabricated by PLD as Source/Drain Electrodes for TFTs

    摘要: Aluminum-doped ZnO (AZO) has huge prospects in the field of conductive electrodes, due to its low price, high transparency, and pro-environment. However, enhancing the conductivity of AZO and realizing ohmic contact between the semiconductor and AZO source/drain (S/D) electrodes without thermal annealing remains a challenge. Here, an approach called pulsed laser deposition (PLD) is reported to improve the comprehensive quality of AZO films due to the high energy of the laser and non-existence of the ion damage. The 80-nm-thick AZO S/D electrodes show remarkable optical properties (transparency: 90.43%, optical band gap: 3.42 eV), good electrical properties (resistivity: 16 × 10?4 ?·cm, hall mobility: 3.47 cm2/V·s, carrier concentration: 9.77 × 1020 cm?3), and superior surface roughness (Rq = 1.15 nm with scanning area of 5 × 5 μm2). More significantly, their corresponding thin film transistor (TFT) with low contact resistance (RSD = 0.3 M?) exhibits excellent performance with a saturation mobility (μsat) of 8.59 cm2/V·s, an Ion/Ioff ratio of 4.13 × 106, a subthreshold swing (SS) of 0.435 V/decade, as well as good stability under PBS/NBS. Furthermore, the average transparency of the unpatterned multi-films composing this transparent TFT can reach 78.5%. The fabrication of this TFT can be suitably transferred to transparent arrays or flexible substrates, which is in line with the trend of display development.

    关键词: PLD,TFT,AZO,transparency,source/drain electrodes

    更新于2025-09-23 15:23:52

  • 141 Induction Heating of TiO 2 Coating on SS Substrate for Photocatalysis 2016 60 3 Induction Heating Consolidation of TiO 2 Sol-Gel Coating on Stainless Steel Support for Photocatalysis Applications

    摘要: A high-frequency induction heater was used to sinter titanium dioxide thin film on stainless steel plates with the aim of being used as photo-electrodes in wastewaters treatment. To validate the use of this sintering technique, the electrodes were prepared using sol-gel and dip-coating, followed by two different annealing processes for comparison: a conventional furnace and a high-frequency induction heating. To characterize the electrodes, X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical and photocatalysis tests were performed. Anatase and rutile phases were obtained for both annealing techniques. A more regular surface morphology was achieved via the induction heating (IH) treatment at 300 oC. The impedance study showed a lower resistance of IH samples, representing an improvement in the charge carrier separation and its fast transfer to the surface of the electrode. The photo-oxidation of methylene blue exhibited a higher degradation compared with the conventional furnace samples prepared in this study.

    关键词: Photocatalysis,Azo dye,Coatings,Electrochemical techniques,Titanium dioxide,Induction heating sintering

    更新于2025-09-23 15:23:52

  • Influence of lateral methyl and terminal substituents on the mesophase behaviour of four rings azo-ester liquid crystal compounds

    摘要: The effect of introducing a lateral methyl substitution into the previously investigated laterally neat four-ring analogues, 4-substituted phenylazo phenyl 4?-(4?-alkoxyphenylazo) benzoates (Ina–e), on their mesophase behaviour was investigated for the newly prepared five homologous series of 4-substituted phenylazo phenyl 4?-(3?-methyl-4?-alkoxyphenylazo) benzoates (IIna–e). Within each homologous series, the alkoxy group varies between 6, 8, 10, 12, 14, and 16 carbons, while the substituent, X, is a polar group that alternatively changes between the electron-donating (CH3O and CH3) groups, and the electron-withdrawing (Br and NO2) groups, including the unsubstituted homologues (IInc). Their mesophase stabilities were determined by DSC and phases identified by PLM. The results showed that independent of the alkoxy-chain length or the polarity of the substituent X, the nematic phase is predominant with relatively high stability and wide temperature ranges. All compounds show a good thermal stability in the mesophases domain, except the nitro and Br substituted derivatives bearing short alkoxy chain length. Comparison of the mesophase behaviour was also made between the present series and corresponding three-ring laterally CH3-substituted azo/ester analogues. UV-vis absorption spectra revealed that derivatives with electron donating or an electron withdrawing groups exhibited redshifts of the π→π* transition compared with unsubstituded derivative.

    关键词: optical properties,polarisability anisotropy,mesophase stability,Four-ring azo/ester/azo derivatives,lateral-methyl substitution

    更新于2025-09-23 15:22:29

  • Synthesis and photochromic properties of azobenzene-derived glycomacrolactones Chaoqi Lin,[a] Stéphane Maisonneuve,[a] Cyril Theulier,[a] and Juan Xie*[a]

    摘要: Reversible photocontrol of glycosides and glycoconjugates structures is a very attractive approach to modulate, in a spatiotemporal way, the various properties and biological activities of carbohydrates. We have synthesized three new azobenzene-derived glycomacrolactones from thioglycopyranosides. The synthesized cyclic glycoazobenzenes can be reversibly photoisomerized between E and Z isomers with high fatigue resistance. 1H NMR study shows that E→Z isomerization of glycomacrocycles induces large conformational change of the macrocyclic structures, without changing sugar 4C1 chair conformation. The Z-glycoazobenzenes can be thermally converted back to the E-isomers. Interestingly, these 16 to 17-membered Z-glycomacrolactones display higher thermal stability than the reported macrocyclic azobenzenes, with the half-life varied from 37 to 72 days. The excellent photoswitching property and bi-stability of the synthesized glycoazobenenes open a new opportunity for the convergent synthesis of diastereomers of glycomacrocycles. Furthermore, chiroptical properties have been observed for both E and Z glycomacrolactones. The geometry of different isomers of macrocycles has been optimized with DFT calculations. Theoretical CD spectra obtained by TD-DFT suggest that the E and Z glycomacrocycles adopt preferentially (P) helical structure for the azobenzene moiety.

    关键词: photochromism,azo compounds,carbohydrates,macrolactones,chirality

    更新于2025-09-23 15:22:29

  • Optical and Structure Analysis of ZnO:Al Film

    摘要: ZnO and ZnO:Al are wide-bandgap semiconductors which have many applications, mainly as transparent conducting films. Thin films of these compounds were deposited onto glass and silicon substrates by RF magnetron sputtering for the investigation of structural and optical characteristics. The XRD results show that the films present wurtzite structure. The formation of a polycrystalline film having a preferential crystallographic orientation in the plane (002) is observed in the doped samples. The Al incorporated films exhibited optical transmittance above 80% in the visible spectrum and a clear absorption band in the infrared due to free carriers. Additionally, the optical band gap around 3.48 eV is significantly above intrinsic ZnO (3.25 eV). Photoluminescence (PL) measurements showed a broad emission band in the visible region. In addition, PL emission lines at 3.32 and 3.37 eV showed up in Al incorporated films, and were related to excitonic emissions. The results show that the Burstein-Moss effect plays a central role in determining the optical characteristics of the doped material.

    关键词: AZO,Zinc Oxide,Burstein-Moss

    更新于2025-09-23 15:21:21

  • Electronic structure and UV–Vis spectra simulation of square planar Bis(1-(4-methylphenylazo)-2-naphtol)-Transition metal complexes [M(L)2]x (M?=?Ni, Pd, Pt, Cu, Ag, and x?=???1, 0, +?1): DFT and TD-DFT study

    摘要: DFT/B3LYP calculations with full geometry optimizations have been carried out on 1-phenylazo-2-naphthol and their metal complexes of formula M(MePhNap)2 (M = Ni, Pd, Pt, Cu, Ag, and MePhNap = 1-(? 4-methylphenylazo)-2-naphtol) in their neutral, oxidized, and reduced forms. The predicted structures provide to the M(II) metal ions the square planar geometry and distorted azo ligand. The TD-DFT theoretical study performed on the optimized geometry allowed us to predict the UV–Vis spectra and to identify quite clearly the spectral position and the nature of the different electronic transitions according to their molecular orbital localization. Large HOMO-LUMO gaps are calculated for all optimized structures suggesting good chemical stabilities, hence, reproducing the available UV–Vis spectra and compared to that of free ligand. The electronic spectra obtained in DMSO and ethanol polar solvents predict more important red shifts than those obtained in hexane as nonpolar one.

    关键词: Electronic transitions,Molecular orbital localization,Metal-ligand coordination,Azo dye

    更新于2025-09-23 15:21:21

  • 4-{(Z)-[4-(Diethylamino)phenyldiazenyl]}phthalonitirle and Phthalocyanines Thereof

    摘要: 4{(Z)-[4-(Diethylamino)phenyldiazenyl]}phthalonitrile was synthesized by diazotization and azo coupling and used to prepare tetrakis-4-(4-{(Z)-[4-(diethylamino)phenyl]diazenyl})phthalocyanine and its cobalt, nickel, zinc and magnesium complexes by template synthesis. The spectral properties of the synthesized compounds were studied.

    关键词: azo chromophore,4-aminophthalonitrile,electronic absorption spectra,metal phthalocyanines

    更新于2025-09-23 15:21:21