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Scalable Deposition of Nanomaterial-Based Temperature Sensors for Transparent and Pervasive Electronics
摘要： This work presents a comparative analysis of materials for planar semitransparent thermocouples fabricated by spray deposition on a flexible substrate. Three different materials are employed to build such devices, analyzing also the effect of the spray order in their final performance. The highest Seebeck coefficient (50.4 μV/K) is found for a junction made of carbon nanotubes (CNTs) on top of silver nanowires (AgNWs) whereas its efficiency in terms of power is the lowest because of the higher sheet resistance of the CNTs. In this case, the best combination for energy-harvesting purposes would be poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and AgNWs, with a power factor of 219 fW/K2. These results prove the feasibility of developing large-scale and cost-effective thermocouples that could be used for sensing or energy-harvesting applications.
关键词： spray deposition,thermocouples,PEDOT:PSS,carbon nanotubes,Seebeck coefficient,silver nanowires,energy harvesting
更新于2025-09-23 15:21:01
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Effect of DI Water Content on the Growth of Anatase TiO<sub>2</sub> Nanotubes Synthesized by Anodization Process
摘要： Vertically aligned anatase TiO2 nanotubes (NTs) were fabricated by anodization of a pure Ti foil in ethylene glycol solutions containing different concentrations of deionized (DI) water. The morphology, elemental composition, and crystallization of TiO2 nanostructures were analyzed by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray spectroscopy (XPS), respectively. The diameter and length of TiO2 NTs were controlled by varying concentrations of DI water. Furthermore, we found that TiO2 NTs in DI water 12 wt. % was suitable for further applications in UV photodetector due to it has a high volume to surface area ratio and long tube. TiO2 NTs have a high potential in various applications such as UV photodetectors, gas sensor, dye sensitized solar cells, and photocatalysts.
关键词： Anatase TiO2,Anodization,Thermal annealing,Titanium dioxide,Nanotubes
更新于2025-09-23 15:21:01
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In situ fluorine doped ZrO2?x nanotubes for efficient visible light photocatalytic activity
摘要： The F-doped ZrO2?x nanotubes are synthesized by anodic oxidization in a F-containing electrolyte and following a low temperature annealing process. The F-doped ZrO2?x nanotubes exhibit a dramatic increase in visible light absorption and efficient visible light photocatalytic activity which are not possessed to normalized ZrO2. The fluorine in anodic ZrO2 nanotubes plays a vital role in the formation of abundant anion vacancies during the annealing. Combining the doping effect of the residual fluorine element, the band gap of the F-doped ZrO2?x nanotubes reduced from 5.13 to 2.35 eV. Moreover, the transient photocurrent response plots and the photocatalytic experiments reveal the highly effective electrons–holes separation of the F-doped ZrO2?x nanotubes and enhanced visible-light photocatalytic degradation for RhB. The degradation rate of RhB in the presence of the F-doped ZrO2?x nanotubes catalyst has reached up to 83% under 2 h low-power LED light irradiation. In addition, the possible photocatalytic mechanism of the F-doped ZrO2?x nanotubes has been proposed via studying the band structure. It is believed that the F-doped ZrO2?x nanotubes will have a bright future for sustainable energy sources and cleaning environment.
关键词： oxygen vacancies,F-doped ZrO2?x nanotubes,anodic oxidization,visible light photocatalytic activity,band gap narrowing
更新于2025-09-23 15:21:01
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Preparation of porous graphene/carbon nanotube composite and adsorption mechanism of methylene blue
摘要： The graphene oxide (GO) and modified carbon nanotubes (MCNTs) were dispersed in water and mixed with toluene to form homogeneous emulsion, then the porous graphene–carbon nanotubes composites (MCG) were prepared through hydrothermal reaction. The adsorption mechanism of MCG was investigated by adsorption methylene blue. The morphology of MCG was analyzed by scanning electron microscope and transmission electron microscopy. It was found that MCG had rich micropore structures and MCNTs were interlaced on graphene sheets. The pore size of MCG can be effectively controlled by changing the volume ratio of toluene to the GO/MCNTs solution in the emulsion. MCG was characterized by X-ray diffractometer, Raman spectrometer, X ray photoelectric instrument and other analytical instruments. It was found that MCG had more oxygen functional groups. The experimental results show that kinetics can be well-described by pseudo-second-order model. The smaller the pore size, the higher the equilibrium adsorption capacity and the slower the adsorption rate. The adsorption thermodynamic parameters show that the adsorption process is spontaneous and belongs to physical adsorption, and high temperature is beneficial to adsorption. The fitting results of MCG-5 equilibrium adsorption data are matched with the Langmuir model and the saturated adsorption capacity is 232 mg g?1. After five cycles of adsorption–desorption operation, the adsorption capacity of MCG-5 decreases slightly.
关键词： Thermodynamics,Graphene,Methylene blue,Carbon nanotubes,Kinetics
更新于2025-09-23 15:21:01
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Thermoluminescence of single wall carbon nanotubes synthesized by hydrogen-arc-discharge method
摘要： Single Wall Carbon Nanotubes (SWNT) synthesized by the hydrogen-arc-discharge method were tested as thermoluminescent (TL) material and found to be highly resistant to gamma radiation. Gamma irradiation of the as-prepared material with doses between 1 and 20 kGy induced changes on the morphology of the SWNT, such as nanoloops, as observed by Scanning Electron Microscopy. From X-ray diffraction, the as-prepared material shows content of various forms of carbon, including nanotubes, hexagonal carbon (graphite), and rhombohedral carbon too. The full width at half maximum (FWHM) of diffraction peaks remain practically unchanged after irradiation. The glow curves show a single TL peak centered at about 449 K. Because the complex structure of the glow curves, it seems that the TL signal could be produced by a trap distribution instead of a single level of traps. To dilucidate the mechanism responsible of glow curves and the value of activation energy of traps, kinetic parameters like Eeff, ?E, and s of experimental the glow curves have been analyzed using computerized glow curve deconvolution (CGCD) considering a continuous distribution of trapping levels, peak shape and initial rise methods, as well as heuristic equations. The measured TL dosimetric properties may be summarized as follows: (a) moderate reproducibility of the TL signal (coefficient of variation 24.87%); (b) main peak activation energy of 1.206 eV; (c) threshold dose of ~1 kGy; (d) TL-sensitivity of ~7.0x10-4; (e) human bone equivalence, i.e., high-Z material, Zeff =15 and, (f) wide linear range of TL dose-response in the range 0.170–2.5 kGy.
关键词： Radiation effects,kinetic property,thermoluminescence,carbon nanotubes,dosimetric material
更新于2025-09-23 15:21:01
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Photocatalytic degradation enhancements of dyes with bi-functionalized zones of modified nanoflower like TiO2 with Pt-C3N4 under sunlight irradiation
摘要： In this work, a novel method was proposed to photodegradation of organic dyes as important pollutants in wastewaters of textile industries. A one-step hydrothermal method was used to directly synthesis nanoflower like TiO2 on ordinary glass (OG) and modified with Pt-C3N4 nanotubes (NFs TiO2/Pt-C3N4) via electrophoretic deposition (EPD) method. Its photocatalytic activity investigated for degradation of three dyes under sunlight irradiation. The properties of NFs TiO2/Pt-C3N4 NTs were characterized by SEM, FT-IR, EDS, and XRD. Reduction of band gap energy and improvement of light absorption in the visible region for the modified photocatalyst were evaluated by using Tauc’s plot method. The experimental result showed that the NFs TiO2/Pt-C3N4 NTs achieved degradation efficiency of <97% at 240 min, towards methylene blue (MB), methyl violet (MV) and malachite green (MG) which are higher than pure TiO2 (68%, 83%, and 71%, respectively). Also as a new strategy, a part of the NFs TiO2/Pt-C3N4 NTs was used as a photoanode of the dye-sensitized solar cell (DSSC) and the other part, placed at a solution as a degradation zone. So with this bi-functionalized system, the degradation time was reduced from 240 min to 120 min with the same degradation efficiency.
关键词： Nanoflowers of TiO2,Pt-C3N4 nanotubes,dye-sensitized solar cells,photodegradation,bi-functionalized system
更新于2025-09-23 15:21:01
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Many-particle excitations in non-covalently doped single-walled carbon nanotubes
摘要： Doping of single-walled carbon nanotubes leads to the formation of new energy levels which are able to participate in optical processes. Here, we investigate (6,5)-single walled carbon nanotubes doped in a solution of hydrochloric acid using optical absorption, photoluminescence, and pump-probe transient absorption techniques. We find that, beyond a certain level of doping, the optical spectra of such nanotubes exhibit the spectral features related to two doping-induced levels, which we assign to a localized exciton X and a trion T, appearing in addition to an ordinary exciton E1. We evaluate the formation and relaxation kinetics of respective states and demonstrate that the kinetics difference between E1 and X energy levels perfectly matches the kinetics of the state T. This original finding evidences the formation of trions through nonradiative relaxation via the X level, rather than via a direct optical excitation from the ground energy state of nanotubes.
关键词： exciton,doping,optical absorption,pump-probe transient absorption,photoluminescence,trion,single-walled carbon nanotubes
更新于2025-09-23 15:19:57
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In-situ formation of ceramic layer on Mo-based composites via laser powder bed fusion
摘要： Poor oxidation resistance is a longstanding disadvantage of Mo-based materials for ultrahigh-temperature applications. In this study, we developed a facile strategy for depositing an in-situ ceramic layer on the surface of Mo-based composites via laser powder bed fusion (L-PBF) using Mo-based alloy powders covered with uniform Al2O3 nanoparticles and bridged by functionalized carbon nanotubes. The surface layer consisted of an α-Al2O3 matrix with a dispersed TiC phase and had a controllable thickness. The formation mechanism of this layer was investigated systematically through single-track observations and finite-element simulation. Moreover, the increased nanohardness can be attributed to the uniformly dispersed, intimately contacted ceramic nanoparticles in the matrix. The results indicated the multifunctionality of L-PBF-processed metallic parts, introducing the possibility of fabricating advanced ultrahigh-temperature materials.
关键词： carbon nanotubes,metal matrix composites,molybdenum,oxidation resistance,laser powder bed fusion
更新于2025-09-23 15:19:57
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Highly solid-luminescent graphitic C <sub/>3</sub> N <sub/>4</sub> nanotubes for white light-emitting diodes
摘要： Graphitic C3N4 (g-C3N4) has seldom been used for white light-emitting diode (LED) phosphors due to its low solid-state fluorescence quantum yield. Here, we report a facile thermal condensation path for the synthesis of g-C3N4 nanotubes stuffed with quantum dots. The g-C3N4 nanotubes have a high fluorescence quantum yield of 30.92% in the solid state. Nitrogen-rich and graphitic carbon-free features are responsible for the enhanced quantum efficiency. The photoluminescence quantum yield can be controlled and improved by the reaction temperature. We finally demonstrate white light emission by coating the highly solid-luminescent g-C3N4 nanotubes as phosphors onto a 370 nm ultraviolet LED.
关键词： graphitic carbon nitride,nanotubes,fluorescence,phosphors,white LEDs
更新于2025-09-23 15:19:57
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Graphene Nanoribbons from Electrostatic-Force-Controlled Electric Unzipping of Single- and Multi-Walled Carbon Nanotubes
摘要： An electrostatic forces (EF) controlled electric unzipping method was developed for producing graphene nanoribbon (GNR) from both the single- (SWCNT) and multi-walled carbon nanotubes (MWCNT). Experimentally, an electrostatic generator was employed by taking its two electrodes with oppositely charges to alternatively link to the metal vessel and the CNT/water solution to form two oppositely electric cycles corresponding to the EF in enhancement or reduction, respectively. Transmission electron microscopy images showed that this applied method can unzip both the SWCNT and MWCNT into relative GNRs. During the EF-controlled electric unzipping process, the concentration increase and EF-controlled in reduction model can produce GNR with enhanced width and quality.
关键词： electrostatic forces control,graphene nanoribbon,Single- and multi-walled carbon nanotubes,electric unzipping,width and quality
更新于2025-09-23 15:19:57