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Light-Induced Sulfur Transport inside Single-Walled Carbon Nanotubes
摘要： Filling of single-walled carbon nanotubes (SWCNTs) and extraction of the encapsulated species from their cavities are perspective treatments for tuning the functional properties of SWCNT-based materials. Here, we have investigated sulfur-modified SWCNTs synthesized by the ampoule method. The morphology and chemical states of carbon and sulfur were analyzed by transmission electron microscopy, Raman scattering, thermogravimetric analysis, X-ray photoelectron and near-edge X-ray absorption fine structure spectroscopies. Successful encapsulation of sulfur inside SWCNTs cavities was demonstrated. The peculiarities of interactions of SWCNTs with encapsulated and external sulfur species were analyzed in details. In particular, the donor–acceptor interaction between encapsulated sulfur and host SWCNT is experimentally demonstrated. The sulfur-filled SWCNTs were continuously irradiated in situ with polychromatic photon beam of high intensity. Comparison of X-ray spectra of the samples before and after the treatment revealed sulfur transport from the interior to the surface of SWCNTs bundles, in particular extraction of sulfur from the SWCNT cavity. These results show that the moderate heating of filled nanotubes could be used to de-encapsulate the guest species tuning the local composition, and hence, the functional properties of SWCNT-based materials.
关键词： X-Ray spectroscopy,encapsulation,illumination,single-walled carbon nanotubes,sulfur,de-encapsulation
更新于2025-09-23 15:19:57
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Rational design of highly efficient flexible and transparent p-type composite electrode based on single-walled carbon nanotubes
摘要： Transparent electrodes are of great importance in electronics and energy technologies. At present, transparent conductive oxides are mainly n-type conductors dominating the market and have restricted the technological advancements. Single-walled carbon nanotubes (SWCNTs) have recently emerged as promising p-type transparent conductor owing to their superior hole mobility, conductivity, transparency, flexibility and possibility to tune the work function. Here, we develop a novel rational design of p-type flexible transparent conductive film (TCF) based on SWCNTs combined with poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), molybdenum oxide and SWCNT fibers. In a configuration of SWCNTs-MoO3-PEDOT:PSS/SWCNT fibers, we achieved a record equivalent sheet resistance of 17 ?/sq with a transmittance of 90% at 550 nm and a high degree of flexibility. We demonstrate that our solar cells developed on the basis of the proposed electrode and hydrogenated amorphous silicon (a-Si:H) yield an outstanding short-circuit current density of Jsc = 15.03 mA/cm2 and a record power conversion efficiency of PCE = 8.8% for SWCNTs/a-Si:H hybrid solar cells. We anticipate that this novel rationally designed p-type TCF opens a new avenue in widespread energy technologies, where high hole conductivity and transparency of the material are prerequisites for their successful implementation.
关键词： Transparent p-type electrode,flexible,composite,single-walled carbon nanotubes,hybrid thin film solar cells
更新于2025-09-19 17:13:59
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Decoration of suspended single-walled carbon nanotubes with soft-landed size-selected metal nanoparticles
摘要： We describe a technique to prepare ensembles of neat, unbundled single-walled carbon nanotubes decorated with pure size-?ltered metal nanoparticles. Polymer-encased nanotubes are drop-cast on nanoporous transmission electron microscope membrane grids, mounted within a nanoparticle-deposition apparatus, baked in situ to remove the polymer coating, and exposed to a beam of pure size-selected metal nanoparticles. Subsequent electron microscopy imaging reveals the presence of nanoparticles supported by pure suspended single-walled nanotubes. This method is promising for e?cient production of prototype chemical and physical devices which require the presence of clean well-de?ned nanoparticle-nanotube hybrids for characterization, imaging, and applications.
关键词： Soft landing,Deposition,Single-walled carbon nanotubes,Size-selected nanoparticles
更新于2025-09-19 17:13:59
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Sonochemical Reaction to Control the Near Infrared Photoluminescence Properties of Single-Walled Carbon Nanotubes
摘要： The effect of ultrasonic irradiation on the optical properties of single-walled carbon nanotubes (SWNTs) was investigated. Upon sonication in D2O in the presence of sodium dodecylbenzene sulfate (SDBS) under air, red-shifted photoluminescence (PL) peaks at ~1043 and ~1118 nm were observed from aqueous suspensions of (6,4) and (6,5)SWNTs, accompanied by a decrease in the intensity of the intrinsic PL peaks. Upon sonication with SDBS under Ar atmosphere, the rate of spectral change increased with the sonication time and new PL peaks emerged at 1043, 1118, and 1221 nm. Meanwhile, upon the addition of 1-butanol, PL peaks emerged only at 1043 nm and 1118 nm, while the emergence of that at 1221 nm was inhibited. On the other hand, a suspension with highly dispersed SWNTs was obtained upon sonication in the presence of sodium cholate without any change in the intrinsic optical properties of SWNTs. These experimental results reveal that the PL characteristics of SWNTs can be controlled by controlling the sonication conditions such as the type of surfactant used, the concentration of SWNTs, reaction environment, and the presence of an inhibitor such as 1-butanol.
关键词： single-walled carbon nanotubes,surfactant,sonochemical reaction,photoluminescence,ultrasonic irradiation
更新于2025-09-19 17:13:59
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Structure-dependent performance of single-walled carbon nanotube films in transparent and conductive applications
摘要： We investigate a complex relationship between structural parameters of single-walled carbon nanotubes (namely, mean length, diameter, and defectiveness) and optoelectrical properties (equivalent sheet resistance) of thin films composed of the nanotubes. We obtained a systematic dataset describing the influence of CO2 concentration and growth temperature. On the basis of the experimental results, we prove the high Raman peak ratio (IG/ID), length, and diameter of the nanotubes to decrease the equivalent sheet resistance of the nanotube-based film. The approach employed highlights the change in the nanotube growth mechanism at the temperature coinciding with the phase transition between α-Fe and γ-Fe catalyst phases. We believe this work to be of high interest for researchers working not only in the field of transparent and conductive films based on nanocarbons, but also for those who reveals the fundamentals of the nanotube growth mechanism.
关键词： aerosol CVD,nanotube growth mechanism,optoelectronic properties,transparent conductive films,single-walled carbon nanotubes
更新于2025-09-19 17:13:59
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Trace level toxic ammonia gas sensing of single-walled carbon nanotubes wrapped polyaniline nanofibers
摘要： This paper presents a two-step enhancement and a comprehensive analysis of single-walled carbon nanotubes (SWCNTs) wrapped polyaniline nanofiber (NPANI) ammonia (NH3) gas sensor at room temperature. SWCNT-PANI composites are successfully synthesized using an efficient and cost-effective rapid in situ chemical polymerization method. The structural morphology and modification of the samples are characterized using field-emission scanning electron microscopy and HRTEM. FTIR and Raman spectroscopic studies are also performed to gain a better insight into the chemical environmental interaction in the as-prepared nanocomposite. The analysis confirms the successful formation of the nanocomposite. The observed NH3 gas-sensing response at 10 ppm of SWCNT, f-SWCNT (functionalised SWCNT), and SWCNT-PANI composite sensors are 5%–6%, 18%–20%, and 24%–25%, respectively. The SWCNT-PANI composite sensors have shown higher repeatability, selectivity, long-term stability, and fast response-recovery characteristics as compared to f-SWCNTs and pristine SWCNT sensors. Concentration and temperature dependent gas-sensing studies are also analyzed. The sensor response also shows a linear relationship with NH3 gas concentration and an inverse relationship with increasing temperature.
关键词： Raman spectroscopy,rapid in situ chemical polymerization,ammonia gas sensor,polyaniline nanofiber,field-emission scanning electron microscopy,FTIR,HRTEM,room temperature,single-walled carbon nanotubes
更新于2025-09-19 17:13:59
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Non-covalent Methods of Engineering Optical Sensors Based on Single-Walled Carbon Nanotubes
摘要： Optical sensors based on single-walled carbon nanotubes (SWCNTs) demonstrate tradeoffs that limit their use in in vivo and in vitro environments. Sensor characteristics are primarily governed by the non-covalent wrapping used to suspend the hydrophobic SWCNTs in aqueous solutions, and we herein review the advantages and disadvantages of several of these different wrappings. Sensors based on surfactant wrappings can show enhanced quantum efficiency, high stability, scalability, and diminished selectivity. Conversely, sensors based on synthetic and bio-polymer wrappings tend to show lower quantum efficiency, stability, and scalability, while demonstrating improved selectivity. Major efforts have focused on optimizing sensors based on DNA wrappings, which have intermediate properties that can be improved through synthetic modifications. Although SWCNT sensors have, to date, been mainly engineered using empirical approaches, herein we highlight alternative techniques based on iterative screening that offer a more guided approach to tuning sensor properties. These more rational techniques can yield new combinations that incorporate the advantages of the diverse nanotube wrappings available to create high performance optical sensors.
关键词： optical biosensing,non-covalent solubilization,selectivity,molecular recognition,near-infrared sensors,single-walled carbon nanotubes (SWCNTs or SWNTs),fluorescence brightness
更新于2025-09-19 17:13:59
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Enhanced field electron emission of single-walled carbon nanotubes prepared by imprinting technique
摘要： In this work, single-walled carbon nanotubes (SWCNTs) field electron emitters were fabricated by imprinting SWCNTs on substrates with a silver buffer layer. It was found that the field emission properties of imprinted SWCNTs were significantly improved with turn-on field at 0.62 V/um and threshold field at 1.04 V/um, comparing to screen-printed SWCNTs emitters who had turn-on field at 1 V/um and threshold field at 2 V/um. These improvements of SWCNTs emitters were owing to the directly imprinting method which made SWCNTs have clean surface and more emitters on the substrates. The lower turn-on electric field of field emission was attributed to no impurities encapsulate on the emitters and the large aspect ratio of SWCNTs resulting in high field enhancement factor of 15800. The emission performance of the imprinted cathode was almost unchanged after many times repeated experiments. This simple and low cost technique can fabricate high performance field emission cathodes efficiently and also demonstrates potential applications in many electronic devices.
关键词： Field enhancement factor,Turn-on field,Imprinting,Field emission,Single-walled carbon nanotubes,Temporal stability
更新于2025-09-19 17:13:59
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Amino-Functionalized Single-Walled Carbon Nanotubes-Integrated Polyurethane Phase Change Composites with Superior Photothermal Conversion Efficiency and Thermal Conductivity
摘要： The development of organic phase change materials (PCMs) with good shape stability, superior photothermal conversion efficiency, and high thermal conductivity is critical for practical photothermal utilizations. Herein, novel form-stable solar-thermal conversion and storage materials (SPCMs) with superior photothermal conversion efficiency and thermal conductivity were successfully synthesized by introducing amino-functionalized single-walled carbon nanotubes (SWNTs?NH2) into poly(ethylene glycol)-based polyurethane PCM. Differential scanning calorimetry (DSC) and thermal conductivity test results showed the SPCMs possessed relatively high phase change enthalpies in the range of 124.0?126.1 J/g and that the introduction of SWNTs?NH2 effectively enhanced the thermal conductivities of SPCMs. Sunlight irradiation experiments showed that the introduction of SWNTs?NH2 into PEG-based polyurethane PCM significantly improved the solar-thermal conversion and storage efficiency of SPCMs from 44.8% to 89.3%. The light irradiation cycling tests and thermogravimetric (TG) analyses indicated that the SPCMs exhibit satisfactory reversible stability and thermal stability. Moreover, SPCMs with SWNTs?NH2 added exhibited much higher solar-thermal conversion and storage efficiency and better reversible stability than SPCM with SWNTs added. In conclusion, the synthesized SPCMs show considerable potential for solar-thermal conversion and storage applications.
关键词： Poly(ethylene glycol),Solar-thermal conversion,Thermal energy storage,Single-walled carbon nanotubes,Phase change materials
更新于2025-09-19 17:13:59
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Sustained photodynamic effect of single chirality-enriched single-walled carbon nanotubes
摘要： Semiconducting single-walled carbon nanotubes (s-SWNTs) are capable of fluorescence emission as well as photothermal and photodynamic actions, resulting from their near-infrared (NIR) absorptions corresponding to their S11 and S22 transitions. Here, we show that one chiral s-SWNTs, (6,4)-SWNTs, photogenerates all three of the major reactive oxygen species, i.e., singlet oxygen (1O2), superoxide anion (O2?–), and hydroxyl radical (?OH), in a sustainable manner. Its efficiency for ?OH generation is dramatically higher than those of the other two chiral s-SWNTs tested, as well as a clinical NIR dye. This sustained and relatively high photodynamic effect in (6,4)-SWNTs is due to their extraordinary high photostability and relatively high generation efficiency of their triplet excited state. In the colloidal stabilization of (6,4)-SWNTs under physiological conditions, a serum protein consisting of a tandem repeat of amphiphilic a -helices is found to be useful for dispersion. The protein-coated (6,4)-SWNTs are capable of effectively ablating cancer cells and disintegrating amyloid beta peptide aggregates through sustained photodynamic action.
关键词： Single-walled carbon nanotubes,Photodynamic effect,Cancer therapy,Reactive oxygen species,Photostability,Amyloid beta peptide
更新于2025-09-19 17:13:59