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oe1(光电查) - 科学论文

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  • Optical modulation studies of multiwall carbon nanotube dispersed in hydrogen bonded ferroelectric liquid crystal mixture for electro-optic devices

    摘要： Structural, optical and electrical properties of multiwall carbon nano-tubes (MWCNT) dispersed liquid crystalline (LC) mixture is extensively studied for electro-optic devices. A small amount of (0.1%) MWCNT is dispersed in cholesteryl stearate (CHS) and 4-dodecyloxybenzoic acid (12OBA) and its mixture is further characterized. Hydrogen bond between the mesogenic compounds are confirmed using FT-IR. Surface morphology and MWCNT dispersion in hydrogen bonded (HBFLC) mixture is established by SEM ferroelectric liquid crystal the mixture using polarizing optical studies. Optical studies of microscope (POM) is recognized by the induced smectic blue phase and smectic A mesogenic phases. Transition temperatures and its corresponding enthalpy values of induced mesophases are analyzed by differential scanning calorimetry (DSC). An interesting observation of optical modulation in the present MWCNT dispersed HBFLC mixture is reported using dielectric studies. Textural modification with respect to external stimulus (bias voltage) in the present HBFLC mixture is reported. Further the field induced phase transitions and improved dielectric permittivity due to the dispersion of MWCNT is also reported.

    关键词： optical modulation,optical shutter,HBFLC,POM,MWCNT

    更新于2025-09-23 15:21:01

  • Immobilization of C/Ce-codoped ZnO nanoparticles on multi-walled carbon nanotubes for enhancing their photocatalytic activity

    摘要： C/Ce-codoped ZnO nanoparticles immobilized onto multi-walled carbon nanotubes (C/Ce-ZnO@MWCNT) were successfully fabricated via the hydrothermal method for degradation of methylene blue (MB) under visible light irradiation. The prepared C/Ce-ZnO@MWCNT samples were characterized by XRD, XPS, FTIR, FE-SEM, EDX, BET, and diffuse reflectance spectroscopy. The obtained results indicated that the photocatalytic activity of all the MWCNTs-containing samples was higher than those of the bare ZnO and C/Ce-codoped ZnO nanoparticles. Besides, the C/Ce-ZnO@MWCNT composite with 50 wt% MWCNT showed the highest photocatalytic activity with the MB removal efficiency of 96.5% recorded within 90 min under visible light illumination using 1.0 g/L catalyst dosage at pH of 9 and MB concentration of 30 ppm. The degradation mechanism controlled by the charge transfer process in C/Ce-ZnO@MWCNT composite was proposed and discussed in detail. In addition, the long-term-use ability of the photocatalyst was also evaluated through experiments conducted in continuous cycles.

    关键词： visible light,C/Ce-ZnO@MWCNT,photocatalytic activity,multi-walled carbon nanotube,methylene blue

    更新于2025-09-23 15:19:57

  • [IEEE 2018 IEEE SENSORS - New Delhi, India (2018.10.28-2018.10.31)] 2018 IEEE SENSORS - Finite Element Modelling and Computational Analysis of Mechanical Properties of Carbon Composite-Based Love Wave Sensor

    摘要： Structured materials are of interest to emphasize the sensitivity of gas or bio-sensors. This work focuses on carbon-polymer composite (PEDOT:PSS-MWCNT) and additional multiwalled carbon nanotubes (MWCNT), deposited by inkjet printing on Love acoustic wave devices. This combination is studied, both with simulation based on finite element modelling and computational analysis of a reduced model, and experimental measurements. This allows for an estimation of the Young modulus of each material: 70 GPa and 150 GPa for the PEDOT:PSS-MWCNT bilayer composite material (? 450nm) and for the MWCNT bilayer on carbon composite (?140nm), respectively. The value is lower than that obtained in the literature, which has been attributed to the material porosity. An enhanced waveguiding effect is observed, which is interesting for further detection applications.

    关键词： MWCNT,PEDOT:PSS,Gas sensor,FEM,SAW,Bio sensor

    更新于2025-09-19 17:15:36

  • Synergistic effect of β-Bi2O3 and graphene/MWCNT in silicone-based polymeric matrices on diagnostic X-ray attenuation

    摘要： The prolonged exposure of high-energy ionizing radiations during treatment of cancer/tumour and radiological examinations is hazardous to occupational workers and patients. Lead-incorporated composite materials are traditionally used as radiopaque fabrics, but are heavy, bulky and hence often cause inconvenience to users. Therefore, superior radiopaque protective wears that are preferably lead-free, light weight and flexible are being explored. Towards this goal, we study here the synergistic effect of graphene nanoplatelets and multi-walled carbon nanotube (MWCNT) on the X-ray attenuation property of polymer nanocomposites containing β-Bi2O3 nanofillers. The effect of graphene and MWCNT at different concentrations on Bi2O3-based polymer nanocomposites is studied to attain optimal compositions with respect to its X-ray attenuation property and thermal stability. Surface topography and surface roughness of the nanocomposite blocks are studied using an atomic force microscope (AFM). The effect of the density of polymer on the curing, thermal stability and X-ray attenuation property is also studied by using silicone polymers of density 1.7 (G1) and 1.04 g/cm3 (G2). The X-ray attenuation property of nanocomposites with G1 polymer matrix is found to be better than that of G2. The G1-based nanocomposite containing β-Bi2O3 and graphene is found to be better than the one with G1 polymer containing β-Bi2O3 and MWCNT. Thermal stability of multifiller nanocomposites is found to be better than the one without nanofillers. AFM topography images show a variation in surface roughness of nanocomposites with different fillers, which contributes to the different micro- and nano-structural architectures due to polymer–nanofiller interaction, thereby, affecting the X-ray attenuation of the nanocomposites. Our study shows that the multifiller nanocomposite containing β-Bi2O3 and graphene nanoplatelets offer greater potential for the development of efficient radiopaque fabric materials.

    关键词： Nanofillers,Graphene,MWCNT,Nanocomposites,Bi2O3,X-ray attenuation

    更新于2025-09-19 17:15:36

  • Performance analysis for hybrid PV/T system using low concentration MWCNT (water-based) nanofluid

    摘要： This paper presents experimental work on utilising Nano?uid as a working agent for Photovoltaic Thermal Systems (PV/T). PV/T systems are one kind of hybrid systems in energy utilisation. They convert the incident solar radiation into two energy types; electricity and heat. In this research, experimental outdoor tests were directed to assess the execution of PV/T system that utilises water-based Multi Walls Carbon Nano Tubes “MWCNT” as a heat storage/heat absorption agent. The e?ect of varying Nano?uid volume concentration ratio was studied within the range (0%:0.3%) while ?xing the circulation rate at 1.2 l/min. By analysing the experimental results, it can be noted that adding Nano Particles to the base ?uid caused the thermal properties to have a signi?cant increment leading the PV/T system to have a better thermal and electrical e?ciency. The best system e?ciencies were obtained at 0.075% V of MWCNTs – water based Nano?uid. At this concentration, a temperature reduction of 12 °C for the PV panel was attained at maximum incident radiation leading to an overall system e?ciency of 83.26%. Also, an average temperature reduction of 10.3 °C was achieved over the daytime leading to an overall e?ciency of 61.23%.

    关键词： Nano?uids,MWCNT,Solar energy,Hybrid PV/T,Photovoltaic

    更新于2025-09-19 17:15:36

  • Ultrasensitive MWCNT/PDMS composite strain sensor fabricated by laser ablation process

    摘要： Flexible ultrasensitive piezoresistive strain sensors were fabricated by CO2 Laser ablating of the surface of the multiwall carbon nanotube/ polydimethylsiloxane (MWCNT/PDMS) composite film prepared by a coating process. The effects of the MWCNT content and the applied laser power on the electrical and sensing performances of the MWCNT/PDMS composite strain sensor were systematically investigated. It is found that, after laser ablating, the electrical conductivity and the sensing gauge factor of the MWCNT/PDMS film were greatly improved only by the addition of 1.0 wt.% of MWCNT, which is below the percolation threshold of the MWCNT in the PDMS matrix. A novel boscage-like structure at the surface of the film formed by the ablation of the PDMS and the rearrangement of the MWCNT during the laser ablating process was found responsible for the ultrahigh gauge factor of the composite strain sensor, which is about 513 at the strain of 5.0%. The facile and cost-effective fabrication process of the flexible ultrasensitive strain sensor could be simply extended to other polymer composites for the development of new multifunctional and wearable electronic devices.

    关键词： Laser ablation,Strain sensor,PDMS,MWCNT

    更新于2025-09-19 17:13:59

  • Surface modification of aluminum alloys with carbon nanotubes by laser surface melting

    摘要： Carbon nanotubes (CNTs) could be an excellent reinforcement for metal matrix composites, specifically for composites with aluminum or aluminum alloy matrix. Surface modification to improve hardness and other material properties has been performed by laser surface melting (LSM) process, where the laser beam melts the substrate together with alloying elements or reinforcing phase additives. In this work, Multiwalled CNTs (MWCNTs) were mixed by the electrostatic adsorption process with aluminum powder and the resulting mixed powder was laser melted on the surface of a 6061-aluminum alloy substrate. As a result, a modified substrate surface has been obtained from the Al/MWCNT – substrate co-melting, dilution and re-solidification processes. This modified layer was obtained by different LSM parameters and were characterized by Optical (OM) and Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Field Emission Gun Scanning Electron Microscopy (FEG-SEM), X-Ray Diffraction (XRD) and Raman Spectroscopy (RS). The resulting mechanical behavior was evaluated by Vickers microhardness tests. The results showed that the presence of MWCNT in the aluminum powder improves the laser energy absorption, leading to the formation of a deeper modified layer, with segregation of Si particles homogeneously dispersed and improving the hardness. The formation of Al4C3 was not observed, evidencing that the MWCNTs did not react with the molten Al matrix during the LSM process.

    关键词： Laser surface melting,MWCNT,Aluminum alloy

    更新于2025-09-16 10:30:52

  • [IEEE 2019 IEEE 9th International Nanoelectronics Conferences (INEC) - Kuching, Malaysia (2019.7.3-2019.7.5)] 2019 IEEE 9th International Nanoelectronics Conferences (INEC) - ITO Islands as Floating Electrodes to Deposit Aligned Carbon Nanotubes for Photovoltaic Applications

    摘要： Recently transparent conductive electrodes (TCEs) have attracted the interest of researchers due to their outstanding optical and electrical properties. Indium tin oxide (ITO) is an oxide material that combines the criteria of high conductance and transmittance. However, ITO is a non-flexible, brittle and expensive material. TCEs are commonly embedded in solar cells to perform high photon absorption and electron collection instantaneously. In this paper, an optimized TCE network is proposed to maintain TCEs’ conductivity and transparency and to improve their flexibility and ability to handle mechanical forces. The network is designed by aligning multi-walled carbon nanotubes (MWCNTs) on ITO speckled surface to form ITO-CNT through grid. The alignment mechanism is achieved by dielectrophoretic (DEP) force, where an electric field of 10V and 105 Hz is subjected to an ethanol/ MWCNT suspension to assemble the CNT across ITO’s floating electrodes.

    关键词： Alignment,DEP,Thin film solar cell,TCEs,MWCNT

    更新于2025-09-12 10:27:22

  • Multi-walled carbon nanotubes /boron oxide composite using plasmonic Ag nanoparticles: Synthesis and SERS characterization

    摘要： In this work, by applying a straightforward and easy technique B2O3 doped MWCNTs synthesized using laser ablation in liquid environment (LALE) method. The plasmonc properties of Ag NPs prepared via Lee-Meisel technique was used to prepare high quality substrates for Surface – enhanced Raman scattering (SERS) measurements The size of Ag NPs was acknowledged by UV/Vis/NIR absorption spectroscopy and SEM imaging (< 50 nm). A rather powerful SERS signal was created due to the plasmonic effect and the presence of Ag NPs. Furthermore, SERS spectra were collected in all the synthesized samples. The concentration level down to 10?4 molar (M) of boron oxide (B2O3) doped samples were detected. The recorded data reveals that an enhancement factor (EF) SERS factor of about 105 can be easily achieved applying this method.

    关键词： SERS,Ag NPs,Boron oxide,MWCNT

    更新于2025-09-11 14:15:04