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Nanotube mode-locked, wavelength and pulsewidth tunable thulium fiber laser
摘要： Mode-locked oscillators with highly tunable output characteristics are desirable for a range of applications. Here, with a custom-made tunable filter, we demonstrate a carbon nanotube (CNT) mode-locked thulium fiber laser with widely tunable wavelength, spectral bandwidth, and pulse duration. The demonstrated laser’s wavelength tuning range reached 300 nm (from 1733 nm to 2033 nm), which is the widest-ever that was reported for rare-earth ion doped fiber oscillators in the near-infrared. At each wavelength, the pulse duration can be regulated by changing the filter’s bandwidth. For example, at ~1902 nm, the pulse duration can be adjusted from 0.9 ps to 6.4 ps (the corresponding output spectral bandwidth from 4.3 nm to 0.6 nm). Furthermore, we experimentally and numerically study the spectral evolution of the mode-locked laser in presence of a tunable filter, a topic that has not been thoroughly investigated for thulium-doped fiber lasers. The detailed dynamical change of the mode-locked spectra is presented and we observed gradual suppression of the Kelly sidebands as the filter’s bandwidth is reduced. Further, using the polarization-maintaiing (PM) cavity ensures that the laser is stable and the output laser’s polarization extinction ratio is measured to exceed 20 dB.
关键词： thulium fiber laser,spectral bandwidth,polarization-maintaiing cavity,Kelly sidebands,tunable wavelength,pulse duration,Mode-locked oscillators,carbon nanotube
更新于2025-11-28 14:23:57
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Rapidly self-heating shape memory polyurethane nanocomposite with boron-doped single-walled carbon nanotubes using near-infrared laser
摘要： In this study, boron-doped single-walled carbon nanotubes (SWCNTs) were synthesized by high-temperature heat treatment (1300 °C) with a boric acid precursor and SWCNTs instead of the conventional chemical doping process. Then, these boron-doped single-walled carbon nanotubes (B-SWCNTs) were added to polyurethane to prepare polyurethane nanocomposites having excellent thermal and mechanical properties. Changes in properties that occurred due to structural changes inside the composite were investigated as the added amount of nanofiller was increased. In particular, a near-infrared (NIR) laser (808 nm) was directly irradiated on the nanocomposite film to induce photothermal properties on the surface of the B-SWCNTs. In the case of the PU nanocomposite film with a filler content of 3 wt%, a self-heating film material that rapidly heated to 250 °C within 10 s was developed. The newly developed material can be applied to electronic devices and products as a heat-generating coating material, de-icing of airplane, a heat sink, for bio-sensing, etc., using a moulding process.
关键词： boron-doping,photothermal,thermoelectrics,carbon nanotube,polyurethane
更新于2025-11-25 10:30:42
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A carbon nanotube-iron (III) oxide nanocomposite as a cathode in dye-sensitized solar cells: Computational modeling and electrochemical investigations
摘要： Here is the evaluating result on the applicability of the multi-walled carbon nanotube (MWCNT) and a-iron (III) oxide (a-Fe2O3) nanocomposite as a cathode material in dye-sensitized solar cells (DSCs). The morphology and the structure of the MWCNT/a-Fe2O3 nanocomposite have characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray elemental mapping analysis. Moreover, the electrochemical performance of the nanocomposite has studied toward the activity of Iˉ/I3ˉ redox couple which represents high current density, low peak-to-peak separation, low charge-transfer resistance, and almost 100% stable response signal. Furthermore, the computational modeling employing the molecular mechanics (MM) and the restricted-Hartree Fock/semiempirical parameterization (RHF/PM6) methods reveals that the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), and the HOMO-LUMO energy gap of the modeled nanocomposite are as (cid:1)6.88, (cid:1)3.62, and 3.26 eV, respectively. These properties match with the electronic-level domino of the DSC structure. Finally, the DSC device has fabricated using N719-sensitized TiO2 photoanode and MWCNT/a-Fe2O3 counter electrode, presenting the open-circuit potential, the short-circuit current density, and the power-conversion ef?ciency of 0.7 V, 20.37 mA cmˉ2, and 6.0%, respectively. This study successfully approves the potential of the nanocomposite as a cathode material in iodine-based dye-sensitized solar cells.
关键词： Dye-sensitized solar cell,Nanocomposite,Carbon nanotube,Molecular mechanics,RHF/PM6,Iron (III) oxide
更新于2025-11-21 11:18:25
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Ultra-selective fiber optic SPR platform for the sensing of dopamine in synthetic cerebrospinal fluid incorporating permselective nafion membrane and surface imprinted MWCNTs-PPy matrix
摘要： Surface plasmon resonance (SPR) based dopamine sensor is realized using the state-of-art technique of molecular imprinting over an optical fiber substrate. Polypyrrole (PPy) is depicted as an effective polymer for the imprinting of dopamine through a green synthesis approach. Sensitivity of the probe is enhanced by the augmenting effect of surface imprinting of dopamine in polypyrrole over multiwalled carbon nanotubes (MWCNTs). To ensure the permselectivity of the probe towards dopamine molecules, a cation exchange polymer, nafion, is utilized as a membrane over imprinted sites to reduce the interference from anionic analytes like ascorbic acid and uric acid at physiological pH. The probe is characterized for a wide range of dopamine concentration from 0 to 10-5 M in artificial cerebrospinal fluid. Various probe parameters are varied to maximize the sensitivity of the sensor. The sensor possesses 18.9 pM as the limit of detection (LOD) which is lowest of those reported in the literature. The manifestation of sensing probe over an optical fiber along with the improved LOD makes the approach highly advantageous in terms of stability, repeatability, online remote monitoring, fast response, and miniaturization for its in vivo/in vitro applications in clinical sensing of dopamine.
关键词： surface plasmon,dopamine,Optical fiber,polypyrrole,nafion,molecular imprinting,sensor,multiwalled carbon nanotube
更新于2025-10-22 19:40:53
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Liquid Crystals - Self-Organized Soft Functional Materials for Advanced Applications || Binary Mixture Composed of Nematic Liquid Crystal and Carbon Nanotubes: A Theoretical Description
摘要： Based on the phenomenological model first presented by van der Schoot et al., which predicts the alignment of carbon nanotube (CNT) dispersions in thermotropic nematic liquid crystals, we present the extensive results concerning the phase diagram and the orientational properties of the mixture in this chapter.
关键词： phase transition,liquid crystal,carbon nanotube
更新于2025-09-23 15:23:52
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Low-power-consumption Fiber-optic Anemometer based on Long-period Grating with SWCNT Coating
摘要： We report a low-power-consumption fiber-optic 'hot wire' anemometer (HWA) based on long-period grating (LPG) with single-wall carbon nanotubes (SWCNTs) coating. A uniform SWCNT film is deposited on a bare LPG acting as both light coupling and sensing element. By carefully selecting the order of the cladding mode and operating wavelength, the LPG shows a much higher temperature sensitivity than that of a regular fiber Bragg grating (FBG). Besides, SWCNT is a single-wall cylindrical nanostructure material with excellent absorption in the infrared range and high thermal conductivity. Due to these two features, the proposed sensor has extremely low power consumption and simple operation by utilizing a broadband light source (BBS) as both heating source and probing light source. A sensitivity of 102.5 pm/(m/s) at the wind speed of 1 m/s was obtained experimentally with 1.6-μm-thick SWCNT film.
关键词： Temperature.,Fiber-optic anemometer,long-period fiber grating,Carbon nanotube
更新于2025-09-23 15:23:52
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Carbon Nanotube-Supported Cu <sub/>3</sub> P as High-Efficiency and Low-Cost Cocatalysts for Exceptional Semiconductor-Free Photocatalytic H <sub/>2</sub> Evolution
摘要： Developing an inexpensive and high-efficiency hydrogen-production cocatalyst to replace the noble metal Pt remains a big challenge in the fields of sustainable photocatalytic hydrogen evolution. Herein, we report the exploration of a high-efficient binary noble metal free Cu3P-CNT H2-evolution cocatalyst by direct high-temperature phosphatizing of Cu(OH)2-CNT. Impressively, combining the advantages of noble metal free Cu3P and carbon nanotube (CNT), the binary Cu3P-CNT cocatalysts show high-efficient photocatalytic H2 evolution in Eosin Y(EY)-contained semiconductor-free photocatalytic systems. The maximum visible-light H2-generation rate for promising EY-Cu3P-CNT systems was 17.22 mmolg-1h-1. The highest apparent quantum efficiency (AQE) could reach 10.23% at 500 nm. More importantly, we found that the separation of photogenerated electrons and holes in the Eosin Y, the efficiency of electron transfer from EY to the active edge sites of Cu3P, and the electrocatalytic H2-evolution activity of Cu3P, could be simultaneously boosted via readily adding the conductive CNT, thus achieving the significantly improved photocatalytic H2 evolution. This work provides a simple and facile strategy to design highly efficient semiconductor-free photocatalytic proton-reduction systems using high-activity transition metal phosphides (TMPs) and inexpensive carbon nanomaterials.
关键词： Photocatalytic Hydrogen Evolution,noble metal-free Cu3P Co-catalysts,Solar Fuel,Carbon nanotube (CNT),Dye sensitization
更新于2025-09-23 15:23:52
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A Novel Multilayer Sandwich Fabric-based Composite Material for Infrared Stealth and Super Thermal Insulation Protection
摘要： At present, infrared stealth materials for advanced detection and stealth technology is usually prepared with low emissivity coating on the surface, but there are very few efficient infrared stealth materials based on textiles with lightweight and flexible features. In this paper, we designed a carbon nanotube-doped aerogel (CNTAs) sandwich structure on polyimide (PI) fabric by hot pressing and then coated with a low emissivity Al-doped ZnO (ZAO) on the outer surface. The surface emissivity lower than 0.5 due to the existence of ZAO and the thermal conductivity of the intermediate interlayer aerogels as low as 0.013 W/(m?K). Additionally, through experiments, theoretical derivation and simulation analysis, we found the resultant composite demonstrated a high infrared stealth performance with super insulation effect, implying it will have a fine prospect in infrared stealth and thermal insulation protection fields with its unique structure and excellent properties.
关键词： Carbon Nanotube-doped Aerogel,Sandwich Structure,Infrared Stealth,Polyimide Fabric,Thermal Insulation,Al-doped ZnO
更新于2025-09-23 15:23:52
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Highly conductive, transparent and metal-free electrodes with a PEDOT:PSS/SWNT bilayer for high-performance organic thin film transistors
摘要： Conductive organic materials including polymers, small molecules, and carbon nanotubes (CNTs) are a promising alternative to inorganic materials in electronic devices. Conventionally, organic electrodes employing CNTs are designed using functionalization of their surfaces or formation of nanocomposites with a conductive polymer. However, phase separation limits the concentration of CNTs in a polymer matrix, hindering the formation of highly dense CNT networks and leading to poor electrical conductivity. In this paper, we introduce bilayer electrodes comprising poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and single-walled CNTs (SWNTs) chemically modified by HNO3 treatment. Impressive conductivities of 2432 and 2438 S cm?1 are found for the SWNT/PEDOT:PSS (S/P) and PEDOT:PSS/SWNT (P/S) electrodes, respectively. Further, an increase in the work function of the electrodes after HNO3 treatment lowers the hole injection barrier, which facilitates hole injection from pentacene. The smooth surface of PEDOT:PSS also contributes to growth of large pentacene grains; consequently, the field-effect mobility of pentacene-based thin film transistors is 1.88 cm2 V?1 s?1 when the P/S electrode is employed. The metal-free electrodes also exhibit a high optical transparency of 88.7%, which suggests that they have great potential for applications in optoelectronics.
关键词： Electrode,PEDOT:PSS,Carbon nanotube,Pentacene,Thin film transistor
更新于2025-09-23 15:23:52
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Fullerene-to-MWCNT Structural Evolution Synthesized by Arc Discharge Plasma
摘要： The growth of multi-walled carbon nanotubes (MWCNTs) has been extensively studied using electron microscopy. The ex situ structural behavior was examined to investigate the growth of the MWCNTs under different environments and pressures using electron microscopy. The arc discharge plasma technique was applied to synthesize the MWCNTs by evaporating carbon through the arc plasma between two cylindrical graphite rods, with a background pressure of 10?2 to 102 mbar, inside a vacuum chamber under different ambient environments. The results showed that long MWCNT structures were successfully grown. We suggest that the mechanism involves: (i) fullerene formation; (ii) the elongation of fullerenes; and (iii) the growth of MWCNTs. Agglomeration with other structures then forms MWCNT bundles. We note that the pressure and environment in the vacuum chamber can affect the structure of the MWCNTs.
关键词： arc discharge,electron microscopy,carbon nanotube,nanostructured
更新于2025-09-23 15:23:52