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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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Reversible Charge Transfer with Singlea??Walled Carbon Nanotubes Upon Harvesting the Low Energy Part of the Solar Spectrum
摘要： Here, the ability of a novel near-infrared dye to noncovalently self-assemble onto the surface of single-walled carbon nanotubes (SWCNTs) driven by charge-transfer interactions is demonstrated. Steady-state, Raman, and transient absorption spectroscopies corroborate the electron donating character of the near-infrared dye when combined with SWCNTs, in the form of fluorescence quenching of the excited state of the dye, n-doping of SWCNTs, and reversible charge transfer, respectively. Formation of the one-electron oxidized dye as a result of interactions with SWCNTs is supported by spectroelectrochemical measurements. The ultrafast electronic process in the near-infrared dye, once immobilized onto SWCNTs, starts with the formation of excited states, which decay to the ground state via the intermediate population of a fully charge-separated state, with characteristic time constants for the charge separation of 1.5 ps and charge recombination of 25 ps, as derived from the multiwavelength global analysis. Of great relevance is the fact that charge-transfer occurs from the hot excited state of the near-infrared dye to SWCNTs.
关键词： doping,charge transfer interactions,noncovalent functionalization,near-infrared dyes,carbon nanotubes
更新于2025-09-19 17:13:59
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Laser graving assisted fabrication of foldable supercapacitors for on-chip energy storage
摘要： Planar supercapacitors (SCs) have been regarded as promising energy devices for on-chip electronics and they should be evaluated by areal performances due to the very limited available areas. However, these SCs usually suffer from inevitable size increase for the requirement of substrates, current collectors and sealants. This work presents a kind of freestanding, foldable and quasi-solid-state SCs that single SC units were stacked in the thickness direction with a common electrode to reduce their occupied areas. The foldable SCs can be fabricated in desired patterns by laser graving and their areal performances increase linearly with the assembled units. The energy density of a 5-units foldable SC is 177.9 μWh cm-2 at the power density of 2.78 mW cm-2 and it outperforms most planar SCs. Therefore, this work provides a new reference to improve the areal properties of on-chip SCs from device design.
关键词： nanocomposites,on-chip energy storage,foldable device,supercapacitors,carbon nanotubes
更新于2025-09-19 17:13:59
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Highly sensitive ultraviolet photodetectors based on single wall carbon nanotube-graphene hybrid films
摘要： An ultraviolet (UV) photodetector was fabricated by depositing single wall carbon nanotubes (SWCNTs) on the surface of a graphene field-effect transistor (GFET) with buried gate electrode structure. A photoresponsivity with a value as high as 204.5 A/W was obtained under a 365-nm LED light illumination with an incident power of 3.9 μW. The photoresponsivity of our photodetector is about four orders higher in magnitude than that of a recently reported UV photodetector, which is based on CNTs/graphene hybrid films with a photoresponsivity of 2.3 × 10?2 A/W. With increasing the source-drain voltage of the SWCNTs modified GFET, the photoresponsivity can be further enhanced. In addition, the photoresponsivity can also be tuned by applying a small gate voltage. This work provides a simple and feasible method to create highly sensitive UV photodetectors based on all-carbon hybrid films, which are important in many applications such as military surveillance, biomedical instrumentation and environmental monitoring.
关键词： Ultraviolet,Graphene field effect transistor,Photodetector,Single wall carbon nanotubes
更新于2025-09-19 17:13:59
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[IEEE 2020 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus) - St. Petersburg and Moscow, Russia (2020.1.27-2020.1.30)] 2020 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus) - Study of Long-term Pulsed Laser Irradiation Effect on SWCNT-Water Dispersion
摘要： In this paper, we studied the effect of long-term pulsed laser radiation from visible range on an aqueous dispersion with single-walled carbon nanotubes with a concentration of 0.005%. The dependence of the normalized temperature dependence, and transmission on nonlinear optical characteristics were determined. In several minutes of irradiation, bubbles appeared in the dispersion and enlightenment was observed, i.e. increase in transmission. It was determined that an aqueous dispersion with carbon nanotubes retains its optical characteristics for 600 pulses at a laser pulses frequency of 10 Hz and power of 230 mW.
关键词： carbon nanotubes,thermograms,pulsed laser radiation,nonlinear optical properties,optical limiters
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
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Influence of single-walled carbon nanotubes functionalization in photocatalytic performance of pyramidal porous silicon: Experimental evidence
摘要： Pyramidal porous silicon (pPSi) synthesized through wet-chemical etching of doped silicon wafer with a large surface area and a wide absorption spectrum are used as a photocatalyst for the photodegradation of methylene blue (MB). The photocatalytic activity of pPSi has been enhanced using single-walled carbon nanotubes (SWCNTs). The role of the SWCNTs on the observed photocatalytic activity enhancement was investigated by analyzing the effect of carbon nanotubes density. SWCNTs loaded in pyramidal porous silicon exhibits a much important photocatalytic activity (52.21% MB degradation in 90 min) in comparison to bare pPSi (11.51% MB degradation in 90 min) under UV light irradiation. This novel nanocomposite can be used as effective photocatalyst for photocatalytic degradation of organic dyes and toxic pollutants and thus is of significant interest for water treatment.
关键词： Carbon nanotubes,Degradation,photocatalytic
更新于2025-09-19 17:13:59
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SnO <sub/>2</sub> ‐CNT Hybrid Electron Transport Layer for Efficient and Hysteresis‐Free Planar Perovskite Solar Cells
摘要： Tin oxide (SnO2) recently has received increasing attention as an electron transport layer (ETL) of planar perovskite solar cells and is considered as a possible alternative to titanium oxide (TiO2). However, planar devices based on pure solution-processed SnO2 ETL still have hysteresis, which greatly limits the application of SnO2 in high-efficiency solar cells. In order to address this issue, here, we fabricate a hybrid ETL of SnO2 and carbon nanotubes (CNTs) by a simple thermal decomposing of a mixed solution of the SnCl4·5H2O and pre-treated CNTs (termed as SnO2-CNT). The addition of CNTs can significantly improve the conductivity of SnO2 films and reduce the trap-state density of SnO2 films, which benefit to carrier transfer from the perovskite layer to the cathode. As a result, a high efficiency of 20.33% has been achieved in the hysteresis-free perovskite solar cells based on SnO2-CNT ETL, which shows 13.58% enhancement compared to the conventional device (PCE=17.90%).
关键词： SnO2,carbon nanotubes,electron transport layer,perovskite solar cells
更新于2025-09-19 17:13:59
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The Effect of Laser Structuring of Carbon Nanotubes on the Proliferation of Chondroblasts and Mesenchymal Stem Cells
摘要： The density of cartilage cells (chondroblasts) proliferating on a silicon substrate coated with vertically oriented arrays of multi-walled carbon nanotubes (MWCNTs) was shown to be higher than on a pure silicon substrate. Electron microscopy showed that the cells in a nutrient medium affected the vertical position of the nanotubes in the array. A method for structuring the MWCNT arrays by 100-ns laser pulse scanning and abrasive water processing on planar substrates was developed. As a result of the structuring of the MWCNTs, the arrays become resistant to bending under the influence of the nutrient medium with mesenchymal stem cells. Structured MWCNT arrays were shown to have no toxic or pathological effect on the viability and morphology of stem cells. Thus, such materials can be suggested for use in cell-adhesive components of biomedical devices.
关键词： carbon nanotubes,laser structuring,mesenchymal stem cells,chondroblasts,cell proliferation
更新于2025-09-19 17:13:59
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Anharmonic Effects in Single-Walled Carbon Nanotubes Analyzed through Low-Temperature Raman Imaging
摘要： The high thermal conductivity of single-walled carbon nanotubes (SWCNT) has gained much attention for their applications in potential thermal devices. Here, we investigate anharmonic effects, originated from phonon interactions, of SWCNT bundles by temperature dependent Raman imaging using our home-built mini cryostat system. The cryostat system is small enough to be mounted on a piezo scanner that suppresses thermal drift, enabling Raman imaging at different temperatures. We obtained Raman spectral images of several SWCNT bundles with a spatial resolution of a few hundred nanometers at different temperatures. We found that different bundles show different temperature dependences of Raman peak intensity, shift, and width. The temperature dependence was further elucidated by considering the sample topography observed by atomic force microscopy, where bundle effects seem to play an important role to influence the anharmonicity. The temperature-dependent Raman analysis based on spatially resolved imaging will be a powerful tool to investigate anharmonic effects of advanced carbon nanomaterials as well as to realize in-situ visualization of thermal properties for future thermal devices.
关键词： single-walled carbon nanotubes,anharmonic effects,low-temperature,Raman imaging,thermal properties
更新于2025-09-19 17:13:59