Sb2S3纳米粒子修饰ZnO纳米片微纳分级结构的光电化学性能

采用恒电位方法,选择氯化钾和乙二胺(EDA)为添加剂,在氧化铟锡(ITO)导电玻璃上制备了高度有序的ZnO纳米片阵列,通过二次电沉积得到了ZnO纳米片上生长纳米棒的微纳分级结构.利用化学浴沉积法在ZnO基底上沉积Sb₂S₃纳米粒子制备出了Sb₂S₃/ZnO纳米片壳核结构和Sb₂S₃/ZnO微纳分级壳核结构.利用扫描电子显微镜(SEM)、X射线衍射(XRD)、紫外-可见(UV-Vis)吸收光谱、瞬态光电流等对其形貌、结构组成和光电化学性能进行了表征和分析.结果表明, Sb₂S₃/ZnO纳米片上生长纳米棒分级壳核结构的光电流明显高于Sb₂S₃/ZnO纳米片壳核结构.在Sb₂S₃/ZnO纳米片壳核结构和Sb₂S₃/ZnO微纳分级壳核结构的基础上旋涂一层P3HT薄膜形成P3HT/Sb₂S₃/ZnO复合结构,以上述复合结构薄膜为光活性层组装成杂化太阳电池,其中, P3HT/Sb₂S₃/ZnO分级壳核结构杂化太阳电池的能量转换效率最高,达到了0.81%.     

Electrochemistry-assisted self-assembly of oriented zinc oxide and long-chain alkyl amine surfactant multilamellar nanostructures

Highly oriented ZnO-surfactant multilamellar nanostructures were fabricated by Electrochemistry-Assisted Self-Assembly on silicon substrates from the solution containing zinc nitrate and dilute surfactant hexadecylamine at 60 °C. The co-absorption of inorganic ions with surfactant on the electrode surface implied that the unique growth mechanism depended strongly on the environmental change of cathodic electrode area under the electric field. The ZnO nanosheets (～2.3 nm) were produced. Comparing with pure ZnO film by electrodeposition, the multilamellar nanostructures consisting of the dielectric organic barriers and the semiconducting inorganic well layers give rise to 2-dimensional quantum confinement. This kind of organic–inorganic hybrid materials may be a potential candidate in practical applications.     

Cadmium selenide-sensitized upright-standing mesoporous zinc oxide nanosheets for efficient photoelectrochemical H_2 production

Cadmium selenide(Cd Se)-sensitized upright-standing mesoporous zinc oxide(ZnO) nanosheets were prepared via a chemical bath deposition followed by annealing and electrochemical deposition of Cd Se quantum dots(QDs). The Cd Se QDs absorb visible photons under sunlight illumination, promoting electrons from the valence band to the conduction band of Cd Se, which then quickly transfer to ZnO followed by the external load to the Pt counter electrode for water reduction. The as-prepared Cd Se/ZnO nanosheets show promising photoelectrochemical activities for hydrogen generation.     

Electrical-optical properties of nanofiber ZnO film grown by sol gel method and fabrication of ZnO/p-Si heterojunction

Electrical and optical properties of the ZnO film prepared by sol-gel dip coating were investigated and ZnO film was deposited onto p-type silicon to obtain Ag/ZnO/p-Si heterojunction diode. Two dimensional atomic force microscopy images indicate that the ZnO film is formed from the fibers consisted from nanoparticles with grain size of 250-350 nm. The electrical conductivity mechanism of the ZnO film was varied from extrinsic to intrinsic conductivity. The calculated optical band gap of the ZnO film was found to be 3.22 eV. The Ag/ZnO/p-Si diode exhibit a non-linear behavior with ideality factor of n = 4.17 and barrier height of ?_B = 0.79 eV. The electrical properties of the Ag/ZnO/p-Si diode were investigated by current-voltage, capacitance-voltage-frequency and conductance-voltage-frequency measurements.     

Controlled synthesis of ZnO with adjustable morphologies from nanosheets to microspheres

The synthesis of ZnO with different morphologies (hexagonal prisms, nanosheets, microspheres and quasi-flowers) was realized through a solvothermal method. During the synthetic procedure, the decomposition of hexamethylenetetramine at the temperature ≥100 °C provided (OH)⁻¹ ions at the rate of good distribution, and sodium dodecyl sulfate was used as templates. By adjusting the basicity in the synthetic system, ZnO nanosheets, or microspheres with nanosheet assemblies were obtained. Adjusting the concentration of surfactant, ZnO hexagonal crystals were formed; by adjusting the synthetic temperature, ZnO quasi-flowers with some nanosheet assemblies were produced. Based on experimental observation and analysis, the forming mechanism was discussed.     

Preparation and characterization of nanocomposite ZnO–Ag thin film containing nano-sized Ag particles: influence of preheating,annealing temperature and silver content on characteristics

Nanocomposite ZnO–Ag thin film containing nano-sized Ag particles have been grown on glass substrate by spin-coating technique using zinc acetate dihydrate as starting precursor in 2-propanol as solvent and monoethanolamine as stabilizer. Silver nanoparticles were added in the ZnO sol using silver nitrate dissolved in ethanol-acetonitrile. Their structural, electrical, crystalline size and optical properties were investigated as a function of preheating, annealing temperature and silver content. The results indicated that the crystalline phase was increased with increase of annealing temperature up to 550 °C at optimum preheating temperature of 275 °C. Thermal gravimetric differential thermal analysis results indicated that the decomposition of pure ZnO and nanocomposite ZnO–Ag precursors occurred at 225 and 234 °C, respectively with formation of ZnO wurtzite crystals. The scanning electron microscopy and atomic force microscopy revealed that the surface structure (the porosity and grain size) of the ZnO–Ag thin film (the film thickness is about 379 nm) was changed compared to pure ZnO thin film. The result of transmission electron microscopy showed that Ag particles were about 5 nm and ZnO particles 58 nm with uniform silver nanoclusters. Optical absorption results indicated that optical absorption of ZnO–Ag thin films decreased with increase of annealing temperature. Nanocomposite ZnO–Ag thin films with [Ag] = 0.068 M and [Ag] = 0.110 M showed an intense absorption band, whose maximum signals appear at 430 nm which is not present in pure ZnO thin films. The result of X-ray photoelectron spectroscopy revealed that the binding energy of Ag 3d_5/2 for ZnO–Ag shifts remarkably to the lower binding energy compared to the pure metallic Ag due to the interaction between Ag and ZnO.     

Microstructure and spatial distribution of corrosion products anodically grown on zinc in chloride solutions

Zinc substrates were electrochemically oxidized in NaCl solution to produce corrosion patinas. XRD, XPS and Raman analyses enabled the identification of simonkolleite and zinc oxide as the patina constituents. FIB-SEM imaging shows that the upper part of the patinas is a network of simonkolleite nanosheets with an open microstructure that is unlikely to act as a significant barrier for corrosion processes. STEM investigations and Raman mapping measurements reveal the presence of a ca. 20–400 nm thin nanoporous ZnO-rich film below the simonkolleite and covering the zinc substrate. Under potentiostatic conditions, the reduced cathodic activity of the patina-covered zinc electrodes is assigned to this nanoporous ZnO layer.     

Facile synthesis of PtSnZn nanosheet thin film at oil–water interface by use of organometallic complexes: An efficient catalyst for methanol oxidation and p‐nitrophenol reduction reactions

PtSnZn nanosheet thin film with stable and high activity towards methanol electro‐oxidation was synthesized via a simple reduction of organometallic precursors including [PtCl₂(cod)] (cod = cis,cis‐1,5‐cyclooctadiene) and [Sn(CH₃)₄] complexes, in the presence of [Zn(acac)₂] (acac = acetylacetonate) complex at toluene–water interface. Catalytic activities of PtSnZn nanosheets were investigated in the p‐nitrophenol (p‐Nip) reduction and methanol oxidation reactions. The obtained results demonstrate that PtSnZn nanosheets exhibit a good electrocatalytic performance for methanol oxidation reaction, the catalytic activity of the PtSnZn nanosheets being at least 3.5 times higher than that of Pt nanoparticle thin film. Also, the apparent rate constant obtained for p‐Nip reduction with the PtSnZn nanosheets is at least 2.3 times higher than that for Pt nanoparticle thin film due to the appropriate interaction between platinum, tin and zinc metals and geometric properties of PtSnZn nanosheet thin film. Nanosheets are highly favourable for superior catalytic performances due to their geometric properties. A facile and efficient route was used to synthesize trimetallic alloy thin film at oil–water interface.     

Influence of Mn incorporation on the structural and optical properties of sol gel derived ZnO film

Undoped and manganese doped ZnO (ZnO:Mn) films were prepared by sol gel method using spin coating technique. The effect of Mn incorporation on the structural and optical properties of the ZnO film has been investigated. The crystalline structure and orientation of the films have been investigated by using their X-ray diffraction spectra. The films exhibit a polycrystalline structure. Mn incorporation led to substantial changes in the structural characteristics of the ZnO film. The scanning electron microscopy (SEM) images of the films showed that the surface morphology of the ZnO film was affected by the Mn incorporation. The transparency of the ZnO film decreased with the Mn incorporation. The optical band gap and Urbach energy values of the ZnO and ZnO:Mn films were found to be 3.22, 3.19 eV and 0.10, 0.23 eV, respectively. The optical constants of these films, such as refractive index, extinction coefficient and optical dielectric constants were determined using transmittance and reflectance spectra. The refractive index dispersion curve of the films obeys the single oscillator model with dispersion parameters. The oscillator energy, E _o , and dispersion energy, E _d, of the films were determined 5.30 and 16.26 eV for ZnO film and 5.80 and 12.14 eV for ZnO:Mn film, respectively.     

Enhanced β‐phase in PVDF polymer nanocomposite and its application for nanogenerator

Harvesting energy from the ambient mechanical energy by using flexible piezoelectric nanogenerator is a revolutionary step toward achieving reliable and green energy source. Polyvinylidene fluoride (PVDF), a flexible polymer, can be a potential candidate for the nanogenerator if its piezoelectric property can be enhanced. In the present work, we have shown that the polar crystalline β‐phase of PVDF, which is responsible for the piezoelectric property, can be enhanced from 48.2% to 76.1% just by adding ZnO nanorods into the PVDF matrix without any mechanical or electrical treatment. A systematic investigation of PVDF‐ZnO nanocomposite films by using X‐ray diffractometer, Fourier transform infrared spectroscopy, and polarization‐electric field loop measurements supports the enhancement of β‐phase in the flexible nanocomposite polymer films. The piezoelectric constant (d₃₃) of the PVDF‐ZnO (15 wt%) film is found to be maximum of approximately −1.17 pC/N. Nanogenerators have been fabricated by using these nanocomposite films, and the piezoresponse of PVDF is found to enhance after ZnO loading. A maximum open‐circuit voltage ~1.81 V and short‐circuit current of 0.57 μA are obtained for 15 wt% ZnO‐loaded PVDF nanocomposite film. The maximum instantaneous output power density is obtained as 0.21 μW/cm² with the load resistance of 7 MΩ, which makes it feasible for the use of energy harvesting that can be integrated to use for driving small‐scale electronic devices. This enhanced piezoresponse of the PVDF‐ZnO nanocomposite film‐based nanogenerators attributed to the enhancement of electroactive β‐phase and enhanced d₃₃ value in PVDF with the addition of ZnO nanorods.     

ZnO-聚苯胺复合膜的制备和性能研究

利用溶胶-凝胶法在Au膜、聚苯胺膜(PANI)和ITO(导电玻璃)基体上制备ZnO纳米微粒膜,初步研究了该微粒膜的形貌,结构和紫外-可见吸收等性质.结果表明,PANI的孔洞结构抑制了ZnO颗粒的团聚,因此,ZnO-PANI复合膜的紫外-可见吸收光谱和荧光光谱相对于ZnO-Au微粒膜有一定程度的蓝移.光电流谱研究同时表明,ZnO-聚苯胺复合膜有望在光电化学方面得到应用.     

The effects of oxygen concentration on ultraviolet luminescence of ZnO films by sol–gel technology and annealing

ZnO thin films were successfully deposited on SiO₂/Si substrate using the sol–gel technique and annealed in various annealing atmospheres at 900 °C by rapid thermal annealing (RTA). X-ray diffraction revealed the (002) texture of ZnO thin films. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that the grains of the ZnO thin film were enlarged and its surface was smoothed upon annealing in oxygen. PL measurement revealed two ultraviolet (UV) luminescence bands at 375 and 380 nm. The intensity of the emission peak at 380 nm became stronger as the concentration of oxygen in the annealing atmosphere increased. The X-ray photoelectron spectrum (XPS) demonstrated that a more stoichiometric ZnO thin film was obtained upon annealing in oxygen and more excitons were generated from the radiative recombination carriers consistently. Additionally, the UV intensity increased with the thickness of ZnO thin film.     

Physical properties of suspension ZnO nanoparticles prepared by wet chemical method: Comparison study

In this work a suspension of Nano-crystalline of ZnO particle is prepared by wet chemical at different temperature and concentration. From FTIR spectral exhibit present of Zn–O bond which indicate to formation ZnO particles. While all suspension and nano films exhibit a high transmittance in visible region about 90% which falls sharply in the UV region. The particle size is measured by using effective mass approximation (EMA), which was approximation (1.7–1.96 nm), and the band gap changes from 3.95 to 4.52eV for nanoparticles in suspension, and change from 3.76 to 3.94 eV for nanoparticles in ZnO film, which is change as function of concentration, temperature and aging time. Hall Effect measurements for ZnO films exhibit n-type conductivity for films deposited with activation energy 0.742eV at high temperature and 0.178eV at low temperature which is different as prepared sample conditions. Also the nanoparticle suspension and nanoparticle film could be implemented as a filter with variable cut off (8.9 × 10¹⁴–1.28 × 10¹⁵) H_Z.     

Preparation of nitrogen doped zinc oxide nanoparticles and thin films by colloidal route and low temperature nitridation process

Nitrogen doped zinc oxide (ZnO) nanoparticles have been synthesized using a colloidal route and low temperature nitridation process. Based on these results, 200 nm thick transparent ZnO thin films have been prepared by dip-coating on SiO₂ substrate from a ZnO colloidal solution. Zinc peroxide (ZnO₂) thin film was then obtained after the chemical conversion of a ZnO colloidal thin film by H₂O₂ solution. Finally, a nitrogen doped ZnO nanocrystalline thin film (ZnO:N) was obtained by ammonolysis at 250 °C. All the films have been characterized by scanning electron microscopy, X-ray diffraction, X-Ray photoelectron spectroscopy and UV–Visible transmittance spectroscopy.     

Preparation of ZnO nanoparticles and characteristics of dye-sensitized solar cells based on nanoparticles film

ZnO nanoparticles were synthesized by hydrolization method and the effects of zinc nitrate concentration and reaction temperature on the resulted particle properties were studied. The transmission of the as-prepared and calcined films and their optical band gaps are measured and calculated respectively. Furthermore, as an application of the ZnO nanoparticles film, dye-sensitized solar cells based on it were successfully fabricated and the cell performances were characterized. The short circuit current for ZnO nanoparticles film DSSCs is 1.35 mA cm^?2, which indicates good value of the prepared film using this technique.     

TiO2/ZnO薄膜电极中光生电子的传输及其在太阳电池中的应用

制备了TiO2纳米颗粒和ZnO纳米棒混合的多孔薄膜电极, 利用瞬态光电压技术研究了染料敏化TiO2/ZnO薄膜中光生载流子的传输特性. 实验结果表明, ZnO纳米棒增加了薄膜中自由电子扩散速率, 减小了复合几率, 改善了能量转换效率.     

Broad spectrum antibacterial zinc oxide-reduced graphene oxide nanocomposite for water depollution

Antimicrobial-resistance (AMR) is a global health challenge arising from the evolution of bacteria, viruses, fungi, and parasites, such that pathogenic microorganisms no longer respond to classical therapies. AMR and the rise of so-called ‘superbugs’ requires innovative nanomaterials and biostatic strategies. Here we report a broad spectrum, antimicrobial nanomaterial integrating light-responsive ZnO nanoparticles (NP) and reduced graphene oxide (rGO) into a heterojunction semiconductor nanocomposite for water depollution. Simultaneous chemical reduction of Zn sulphate and GO sheets yields a low concentration (0.5 mol%) of 10 nm ZnO nanoparticles decorating fragmented rGO nanosheets, with a total surface area of 12 m²/g and optical band gap of 1.6 eV. Antimicrobial performance of the ZnO-rGO nanocomposite was evaluated against methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli 0157:H7 and Salmonella typhimurium bacteria, which are prevalent in contaminated aquatic systems; antimicrobial efficacy against these organisms was 96%, 97%, and 73%, respectively, for a loading of 2 mg/mL, evidencing a strong synergy compared with pure ZnO or rGO components. ZnO-rGO was also an effective photocatalyst for the aqueous degradation of Malachite Green dye, suggesting that its mode of antibacterial action reflects the production of reactive oxygen species under ambient illumination.     

Green synthesis of graphene nanosheets/ZnO composites and electrochemical properties

A green and facile approach was demonstrated to prepare graphene nanosheets/ZnO (GNS/ZnO) composites for supercapacitor materials. Glucose, as a reducing agent, and exfoliated graphite oxide (GO), as precursor, were used to synthesize GNS, then ZnO directly grew onto conducting graphene nanosheets as electrode materials. The small ZnO particles successfully anchored onto graphene sheets as spacers to keep the neighboring sheets separate. The electrochemical performances of these electrodes were analyzed by cyclic voltammetry, electrochemical impedance spectrometry and chronopotentiometry. Results showed that the GNS/ZnO composites displayed superior capacitive performance with large capacitance (62.2 F/g), excellent cyclic performance, and maximum power density (8.1 kW/kg) as compared with pure graphene electrodes. Our investigation highlight the importance of anchoring of small ZnO particles on graphene sheets for maximum utilization of electrochemically active ZnO and graphene for energy storage application in supercapacitors.     

Improving performance of ZnO Schottky photodetector by inserting MXenes modified-layer

The development of low-cost and high-performance ZnO Schottky photodetectors (PDs) has drawn intensive attention, but still a challenge due to their poor conductivity and low light utilization efficiency. Here, we introduce Ti₃C₂T_X into ZnO films to fabricate Schottky UV PDs via facile spin-coated method. The fabricated ZnO/Ti₃C₂T_X/ZnO compound film shows outstanding performance on photocurrent, responsivity, noise equivalent power (NEP), normalized detection rate (D*), and linear dynamic region (LDR), compared with the original ZnO device. The photocurrent is significantly increased by 466%, and the responsivity is improved by one order of magnitude. In addition, it exhibits relatively low NEP (5.99 × 10⁻¹¹ W), strong D* (2.53 × 10⁹ Jones), and high LDR (28 dB). The superior performance is ascribed to the enhanced conductivity and light absorption of ZnO film after introduction of Ti₃C₂T_X modification layer, leading to simultaneously faster electron transfer, lower the radiation recombination of electron and holes on the ZnO/Ti₃C₂T_X/ZnO compound film. This work provides a facile way to develop low-cost and high-performance ZnO Schottky PDs.     

Chemical bath deposition of CdS quantum dots on vertically aligned ZnO nanorods for quantum dots-sensitized solar cells

Formation of CdS quantum dots (Q dots) on the vertically aligned ZnO nanorods electrode was carried out by chemical bath deposition. The diameter and thickness of ZnO nanorods are ～100–150 nm and ～1.6 μm, respectively, and CdS Q dots on ZnO nanorods have a diameter of smaller than 15 nm. In application of the Q dots-sensitized solar cells, composite film exhibited a power conversion efficiency of 0.54% under air mass 1.5 condition (80 mW/cm²), and incident-photon-to-current conversion efficiency showed 18.6%.