- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Template growth of Au/Ag nanocomposites on phosphorene for sensitive SERS detection of pesticides
摘要： We report template growth and dense packing of noble metallic nanoparticles on few-layer phosphorene for sensitive SERS detection. Phosphorene obtained by electrochemical exfoliation serves as both the template and reductant in the fabrication of noble metallic nanoparticles which are dispersed on phosphorene without aggregation or pile-up. The BP/Ag/Au and BP/Au/Ag nanocomposites with a nanogap structure exhibit excellent SERS sensitivity and reproducibility with respect to Rhodamine 6G (R6G). The BP/Au/Ag nanocomposite is further utilized as the SERS substrate for the detection of two fungicides, thiabendazole and thiram, and detection limits of 10-7 and 10-8 M are achieved. Template growth of Au/Ag nanocomposites is demonstrated to be a green strategy for the fabrication of SERS substrates and has large potential in applications such as pesticide detection.
关键词： template growth,nanocomposites,phosphorene,SERS
更新于2025-11-21 11:01:37
-
G‐C3N4‐SiC‐Pt for Enhanced Photocatalytic H2 Production from Water under Visible Light Irradiation
摘要： The g-C3N4 and SiC has drawn increasing attention for application to visible light photocatalytic hydrogen evolution from water splitting due to their unique band structure and high physicochemical stability. In this study, g-C3N4-SiC heterojunction with loaded noble metal was constructed. The g-C3N4-SiC-Pt composite photocatalysts were successfully prepared by the combination method of a bio-reduction, sol-deposition and calcination. The layers of g-C3N4 were thinned and the SiC and Pt nanoparticles simultaneously were tightly bound to g-C3N4 by calcination in the process of preparing the g-C3N4-SiC-Pt. The heterojunction formed in the interface of SiC and g-C3N4 enhances the separation efficiency of the photogenerated electron-hole pairs. These composite photocatalysts achieve a high hydrogen evolution rate of 595.3 μmol·h-1·g-1 with a 1wt% of deposited Pt, 3.7- and 2.07-fold higher than g-C3N4-bulk and g-C3N4-SiC under visible-light irradiation with a quantum efficiency of 2.76% at 420 nm, respectively.
关键词： visible light,g-C3N4-SiC-Pt photocatalysts,hydrogen evolution,photocatalysis
更新于2025-11-21 11:01:37
-
Highly sensitive and selective room-temperature NO2 gas-sensing characteristics of SnOX-based p-type thin-film transistor
摘要： The high-performance p-type metal-oxide-semiconductor (MOS)-based gas sensor is an important subject of research in the field of gas-sensing technology. In this work, we demonstrated a p-type MOS-based thin-film transistor (TFT) nitrogen dioxide (NO2) gas sensor that used tin oxide (SnOX) for both the channel and sensing layers. The crystalline status, surface morphology, and atomic-bonding configuration of the thin-film were examined using X-ray diffraction, field emission-scanning electron microscopy, and X-ray photoelectron spectroscopy. The results indicated that the deposited thin-film was mainly composed of polycrystalline SnO with a tetragonal structure. The fabricated p-type SnOX TFT showed a maximum response value of 19.4-10 ppm NO2 at room temperature (RT, 25 °C) when operated in the subthreshold region, which was significantly higher than that of 2.8–10 ppm NO2 obtained from a p-type SnOX thin-film chemiresistor at RT. In addition, the SnOX TFT gas sensor showed significantly higher sensitivity to NO2 gas than to other target gases such as NH3, H2S, CO2, and CO at RT. To the best of our knowledge, this is the first study to a p-type MOS-based field-effect transistor-type gas sensor. Our experimental results demonstrate that the p-type SnOX TFT is a promising gas sensor that can operate at RT with high sensitivity and selectivity to NO2 gas.
关键词： SnO,Thin-film transistor,NO2 gas sensing,SnOX,P-type metal oxide semiconductor
更新于2025-11-21 11:01:37
-
Alignment of liquid crystals using Langmuir?Blodgett films of unsymmetrical bent-core liquid crystals
摘要： The properties of the thin films of liquid crystal (LC) molecules can be governed easily by external fields. The anisotropic structure of the LC molecules has a large impact on the electrical and optical properties of the film. The Langmuir monolayer (LM) of LC molecules at the air–water interface is known to exhibit a variety of surface phases which can be transferred onto a solid substrate using the Langmuir?Blodgett (LB) technique. Here, we have studied the LM and LB films of asymmetrically substituted bent-core LC molecules. The morphology of LB film of the molecules is found to be a controlling parameter for aligning bulk LC in the nematic phase. It was found that the LB films of the bent-core molecules possessing defects favour the planar orientation of nematic LC, whereas the LB films with fewer defects show homeotropic alignment. The defect in LB films may introduce splay or bend distortions in the nematic near the alignment layer which can govern the planar alignment of the bulk LC. The uniform layer of LB film facilitates the molecules of nematic to anchor vertically due to a strong van der Waals interaction between the aliphatic chains leading to a homeotropic alignment.
关键词： field emission scanning electron microscope,atomic force microscope,Langmuir?Blodgett film,liquid crystals,Brewster angle microscopy,Langmuir monolayer
更新于2025-11-21 11:01:37
-
Effects of Sn doping on the optoelectronic properties of reactively evaporated In4Se3 thin films
摘要： Polycrystalline In4Se3: Sn thin films are prepared on glass substrate by reactive evaporation under a vacuum of 10?5 mbar. The characterizations of the samples are done using XRD, FESEM, XPS and UV-Vis-NIR spectrophotometer. The optical band gap shift of the sample, above the carrier concentration of 1.833 × 1017 cm?3, is well described by Burstein-Moss model. The resistivity of the samples is found to decrease as a result of Sn incorporation. Our results show that in all samples, impurity scattering and lattice vibration scattering are the main factors affecting the electrical properties. Photoconductivity studies at room temperature show that visible photoresponsivity of the films increases with increase in Sn concentration. These improvements in optoelectronic properties facilitate the usefulness of such films in device applications.
关键词： Sn doped In4Se3 thin films,Reactive evaporation,Burstein-moss effect
更新于2025-11-21 11:01:37
-
Fabrication of Fe-doped SrTiO3 photocatalyst with enhanced dinitrogen photofixation performance
摘要： SrTiO3 as semiconducting photocatalyst has been extensively investigated due to its band edges meeting the thermodynamic requirements for water splitting, but a few attention has been concentrated on its application in the NH3 synthesis via N2 photofixation process. Herein, Fe-doped SrTiO3 (FexSr1-xTiO3) products (0 ≤ x ≤ 0.20) were synthesized via a hydrothermal process followed by calcination at 700oC. All FexSr1-xTiO3 products (0.03 ≤ x ≤ 0.20) deliver an enhanced N2 fixation ability, and FexSr1-xTiO3 (x = 0.10) achieves the best NH3 production activity of 30.1 μmol g-1 h-1, which is 3.2-hold higher than that of SrTiO3 alone. Once the x value is higher than 0.10, FexSr1-xTiO3 will transform into composites containing Fe-doped SrTiO3 and α-Fe2O3, which acts as charge recombination sites, thus causes a decreased N2 fixation activity. Further investigations demonstrate that the surface Fe3+-doped sites can not only chemisorb and activate N2 molecules, but also promote the interfacial electron transfer from Fe-doped SrTiO3 to N2 molecules, and thus significantly improve the N2 fixation ability. The present Fe-doped SrTiO3 products exhibit characteristic features such as stable and efficient N2 fixation ability as well as simultaneous realization of N2 reduction and H2O oxidation without co-catalyst, which are of significance in artificial photosynthesis with H2O as electron and proton sources.
关键词： Photocatalysis,Fe-doped SrTiO3,Dinitrogen photofixation,N2 molecule activation
更新于2025-11-21 11:01:37
-
Near-Infrared Light-Driven Controllable Motions of Gold-Hollow-Microcone Array
摘要： Micro/nanomotors can effectively convert other forms of energy into mechanical energy, which have been widely used in microscopic fields. However, it is still challenging to integrate the micro/nanomotors to perform complex tasks for broad applications. Herein, a new mode for driving the collective motion behaviors of integrated micro/nanomotors in a liquid by plasmonic heating is reported. The integrated micro/nanomotors, constituted by gold hollow microcone array (AuHMA), are fabricated via colloidal lithography. Owing to the excellent plasmonic-heating property of AuHMA, the integrated micro/nanomotors can generate vapor bubbles in the liquid as exposure to near-infrared (NIR) irradiation, therefore inducing versatile motions via on/off NIR irradiation. The floating-diving motions are reversible for at least 60 cycles without fatigue. In addition, precise manipulation of the coordinated motion behaviors, including bending, convex, and jellyfish-like floating motions, can be realized by adjusting the irradiated positions of incident NIR light together with the sizes and shapes of AuHMA films. Moreover, the AuHMA film can act as a robust motor to drive a foam craft over 57 folds of its own weight as exposure to NIR irradiation. Our investigation into the NIR-driven AuHMA film provides a facile approach for obtaining integrated micro/nanomotors with controllable collective motions, which holds promise in remotely controlled smart devices and soft robotics in liquids.
关键词： motor,plasmonic heating,gold hollow microcone,controllable motions,light-driven
更新于2025-11-21 11:01:37
-
SEM Image Distortion Measurement Based on Silver Nanowires
摘要： In scanning electron microscopy, electromagnetic distortion is one of the main causes of pattern distortion. This distortion typically manifests as periodic vibration at high frequency scanning speeds. The article establishes a model for describing the pattern distortion when the edge of the sample is inconsistent with the scanning direction. As the basis for distortion solutions.
更新于2025-11-21 11:01:37
-
Post-synthesis phase and shape evolution of CsPbBr3 colloidal nanocrystals: The role of ligands
摘要： The surface chemistry of colloidal cesium lead bromide (CsPbBr3) nanocrystals is decisive in determining the stability and the final morphology of this class of materials, characterized by ionic structure and a high defect tolerance factor. Here, the high sensitivity of purified colloidal nanocubes of CsPbBr3 to diverse environmental condition (solvent dilution, ageing, ligands post synthetic treatment) in ambient atmosphere is investigated by means of a comprehensive morphological (electron microscopy), structural (θ/2θ X-ray diffraction (XRD) and grazing incidence wide angle scattering (GIWAXS)), and spectroscopic chemical (1H nuclear magnetic resonance (NMR), nuclear Overhauser effect spectroscopy (NOESY), absorption and emission spectroscopy) characterization. The aging and solvent dilution contribute to modify the nanocrystal morphology, due to a modification of the ligand dynamic. Moreover, we establish the ability of aliphatic carboxylic acids and alkyl amines ligands to induce, even in a post preparative process at room temperature, structural, morphological and spectroscopic variations. Upon post synthesis alkyl amine addition, in particular of oleyl amine and octyl amine, the highly green emitting CsPbBr3 nanocubes effectively turn into one-dimensional (1D) thin tetragonal nanowires or lead halide deficient rhombohedral zero-dimensional (0D) Cs4PbBr6 structures with a complete loss of fluorescence. The addition of an alkyl carboxylic acid, as oleic and nonanoic acid, produces the transformation of nanocubes into still emitting orthorombic two-dimensional (2D) nanoplates. The acid/base equilibrium between the native and added ligands, the adsorbed/free ligands dynamic in solution and the ligand solubility in non-polar solvent contribute to render CsPbBr3 particularly sensitive to environmental and processing conditions and, therefore prone to undergo to structural, morphological and, hence spectroscopic, transformations.
关键词： lead halide perovskite nanocrystals,surface chemistry,ligands equilibria,long term stability
更新于2025-11-21 11:01:37
-
Role of chamber pressure on crystallinity and composition of silicon films using silane and methane as precursors in hot-wire chemical vapour deposition technique
摘要： Hot-wire chemical vapour deposition is a versatile technique to deposit a-Si:H and nc-Si films at higher deposition rate (~5-10 ?/sec) as compared to Plasma enhanced chemical vapour deposition (1-2 ?/sec). We report the deposition of highly crystalline Si films at very high deposition rate (≥ 40?/sec) by adding methane to silane during thermal/catalytic decomposition. A series of films were deposited by varying the chamber pressure between 10-100 Pa at a substrate temperature of 300 °C and filament temperature 2000 °C. The hydrogen diluted silane (10% silane in hydrogen) and pure methane were used as precursors and gas flow rate ratio was kept constant at 10. Films prepared at lower pressure (≤ 20 Pa) were more crystalline and do not contain any trace of carbon atoms. Bandgap was found to increase from 1.24-1.63 eV when pressure was increased. It was observed that chamber pressure plays a key role in determining the crystallinity, disorder and composition of these films. Addition of methane to hydrogen diluted silane increased deposition rate and crystallinity of Si films at low pressure (≤ 20 Pa). Above 20 Pa pressure, carbon atoms signature was obtained. SiC films were obtained when pressure was > 100 Pa.
关键词： Deposition rate,Si films,Crystallinity,Hot-wire chemical vapour deposition
更新于2025-11-21 11:01:37