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- Carbon nanotubes
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- University of British Columbia
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A comparative study on photocatalytic hydrogen evolution activity of synthesis methods of CDs/ZnIn2S4 photocatalysts
摘要： The introduction of carbon materials in photocatalytic systems can significantly enhance the photocatalytic hydrogen evolution activity. Here, we proposed and fabricated carbon nanodots/ZnIn2S4 (CDs/ZIS) samples via three methods. The morphology, chemical elements and valence, and photoelectric properties of CDs/ZIS samples were systematically characterized by SEM, TEM, XPS, UV and PL. The photocatalytic H2 production experiments indicate that the photocatalytic performance of all CDs/ZIS samples has been significantly improved, which could be attributed to the fact that serving as an excellent electron acceptor, CDs can accelerate the separation efficiency of photogenerated electrons and holes. The samples prepared via one-pot hydrothermal method exhibit the optimal photocatalytic activity and the corresponding H2 production rate of 4.15 mmol g?1 h?1 under visible light irradiation (λ > 420 nm), which is about 2.92 times higher than pure ZIS. Our work presented the influence of synthetic method on photoelectric performance and photocatalytic activity of CDs/ZIS nanocomposites, and provided a reliable idea for improving the photocatalytic performance of photocatalyst toward practical applications.
关键词： Synthesis methods,ZnIn2S4,Photocatalytic hydrogen evolution,Carbon dots
更新于2025-11-14 15:29:11
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Rapid preparation of homogeneous carbon dots with yellow fluorescence and formation mechanistic investigation
摘要： In this study, homogeneous carbon dots with yellow fluorescence and high absolute fluorescence quantum yields (78.6%) were firstly prepared through a one-step solvothermal method without complicated process of separation, in which sodium citrate, carbamide, and anhydrous calcium chloride were adopted as precursors, while toluene was selected as solvent. The as-prepared carbon dots with an average size of 5.9 nm have a high degree of crystallinity. According to the discussion of the formation mechanism carbon dots, it is found that the toluene guarantee the formation of crystalline core and Ca2+ promotes the formation of carbonaceous core with high crystallinity, which is responsible for the ultrahigh quantum yield. Furthermore, the fluorescent properties of carbon dots are excellent in organic solvents and could be quenched by water, making them a promising material used without any modification in the detection of water in organic solvents, which has a great influence on organic chemical reaction, and may even determine the resultant, yield, and selectivity of organic reaction.
关键词： Detection of water content,Ultrahigh quantum yield,Yellow fluorescence,Carbon dots,Quantum dot
更新于2025-11-14 15:28:36
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Solubilization of Carbon Nanotubes with Ethylene-Vinyl Acetate for Solution-Processed Conductive Films and Charge Extraction Layers in Perovskite Solar Cells
摘要： Carbon nanotube (CNT) solubilization via non-covalent wrapping of conjugated semiconducting polymers is a common technique used to produce stable dispersions for depositing CNTs from solution. Here, we report the use of a non-conjugated insulating polymer, ethylene vinyl acetate (EVA), to disperse multi- and single-walled CNTs (MWCNT and SWCNT) in organic solvents. We demonstrate that despite the insulating nature of the EVA, we can produce semitransparent films with conductivities of up to 34 S/cm. We show, using photoluminescence spectroscopy, that the EVA strongly binds to individual CNTs, thus making them soluble, preventing aggregation, and facilitating the deposition of high-quality films. To prove the good electronic properties of this composite, we have fabricated perovskite solar cells using EVA/SWCNTs and EVA/MWCNTs as selective hole contact, obtaining power conversion efficiencies of up to 17.1%, demonstrating that the insulating polymer does not prevent the charge transfer from the active material to the CNTs.
关键词： perovskite solar cells,carbon nanotubes,insulating polymer,conductive films,CNT polymer functionalization
更新于2025-11-14 15:25:21
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Facile synthesis of yellow emissive carbon dots with high quantum yield and their application in construction of fluorescence-labeled shape memory nanocomposite
摘要： Synthesizing carbon dots (CDs) with efficient long-wavelength emissions (i.e., yellow- to red light) generally suffer from sophisticated approaches, time-consuming process, harsh conditions, and requirement of organic solvent; also, a further limitation of the resulting CDs is relatively low quantum yield (QY) in aqueous solution. Herein, novel yellow emitting CDs (Y-CDs) with a considerable QY of 62.8% were synthesized from a precursor comprising resorcinol and o-phenylenediamine via a facile microwave method. To probe the fluorescence mechanism, another typical resorcinol-derived CDs using ethylenediamine as dopant were fabricated as well, showing strong green emission with an absolute QY of 60.6%. Spectroscopic and structural characterizations indicated that the distinct redshift of green to yellow emission depended on the dimension of conjugated sp2-domain and the content of graphitic N heavily, while the excellent QY was highly related to the low proportion of defective sp2 carbon cluster and high nitrogen content within CDs. Moreover, the Y-CDs were confirmed to be capable of introducing additional crosslinking points in poly(vinyl alcohol) (PVA) polymer, which resulted in the Y-CDs-contained nanocomposite behaving superior and tunable water-induced shape recovery performances. Importantly, since being labeled with long-wavelength emission, the responsiveness of PVA/Y-CDs composite will contribute to its versatile utilization in biology-relevant fields.
关键词： shape recovery,fluorescence mechanism,yellow emission,carbon dots,nanocomposite
更新于2025-11-14 15:23:50
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Full color carbon dots through surface engineering for constructing white light-emitting diodes
摘要： White light-emitting diodes (WLEDs) devices are replacing the filament lamp and they can provide a light close to the natural sunlight, which have thus drawn considerable attention in these recent years. It remains a scientific challenge to develop WLEDs using environmentally friendly, easy-to-process and cost-effective phosphors. Here we synthesized blue-, green- and red-carbon dots (denoted as B-, G- and R-CDs) by a facile solvothermal method with high dispersity both in aqueous and organic solvent. The quantum yield (QY) of the R-CDs achieved up to 24.7%. These CDs can be easily dissolved in polyvinylpyrrolidone (PVP) colloid, leading to the production of ultraviolet (UV)-excited LED devices to avoid the retinal damage caused by blue ray excitation. The fluorescence emission of the WLED has a wide band, covering the whole visible light region. Importantly, the influence of doping that gives rise to the change of emissive colors has been elucidated by X-ray photoelectron spectroscopy (XPS) combined with a computation method in order to provide a systematic controllable tuning on the functionalization of CDs. As such, WLEDs were demonstrated with color coordinates of (0.33, 0.33), a color temperature of 5612 K in the CIE chromaticity diagram with good anti-photobleaching and a color rendering index (CRI) of 89.
关键词： polyvinylpyrrolidone,White light-emitting diodes,solvothermal method,UV-excited LED devices,density functional theory,quantum yield,X-ray photoelectron spectroscopy,carbon dots
更新于2025-11-14 15:18:02
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Non-enzymatic sensing of dopamine by localized surface plasmon resonance using carbon dots-functionalized gold nanoparticles
摘要： A highly selective, sensitive, and rapid colorimetric sensor for the determination of dopamine (DA) was developed using the color change of S-doped carbon dots functionalized gold nanoparticles (S-CDs@Au NPs). The base of the method is the formation of a complex between the amine groups of dopamine with carboxylic groups of S-CDs@Au NPs followed by their aggregation with Fe3+ ions which acts as the linkers causing a red shift from 520 to 670 nm in the localized surface plasmon peak of S-CDs@Au NPs. The ratio of absorbance intensity at 670 nm to 520 nm was monitored as the analytical signal for determination of dopamine. The parameters affecting the analytical signal including reaction time, solution pH, the concentration of Au NPs and concentration of Fe3+ were optimized. At optimized conditions, the calibration curve was linear in the concentration range of 0.81-16.80 μM of dopamine. The detection and quantification limits were 0.23 μM and 0.77 μM, respectively. The intra-day and inter-day relative standard deviation (RSDs) at 5.0 μM of DA were 3.9% and 5.6%, respectively (n = 5). The applicability of the method for determination of DA in dopamine ampoule, urine and serum human samples was investigated.
关键词： Carbon dots,Localized surface plasmon resonance,Colorimetric chemical sensor,Dopamine,Gold nanoparticles
更新于2025-11-14 15:18:02
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Templated direct growth of ultra-thin double-walled carbon nanotubes
摘要： Double-walled carbon nanotubes (DWCNTs) combined the advantages of multi-walled (MW-) and single-walled (SW-) CNTs can be obtained by transforming the precursors (e.g. fullerene, ferrocene) into thin inner CNTs inside SWCNTs as templates. However, this method is limited since the DWCNT yield is strongly influenced by the filling efficiency (depending on the type of the filled molecules), opening and cutting the SWCNTs, and the diameter of the host SWCNTs. Therefore, it cannot be applied to all types of SWCNT templates. Here we show a universal route to synthesize ultra-thin DWCNTs via making SWCNTs stable at high temperature in vacuum. This method applies to different types of SWCNTs including metallicity-sorted ones without using any precursors since the carbon sources were from the reconstructed SWCNTs and the residue carbons. The resulting DWCNTs are with high quality and the yield of inner tubes is comparable to/higher than that of the DWCNTs made from the transformation of ferrocene/fullerene peapods.
关键词： Double-walled carbon nanotubes,ultra-thin,high-temperature annealing,DWCNTs,SWCNTs
更新于2025-11-14 15:16:37
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AIP Conference Proceedings [Author(s) 2ND INTERNATIONAL CONFERENCE ON CHEMISTRY, CHEMICAL PROCESS AND ENGINEERING (IC3PE) - Yogyakarta, Indonesia (14 August 2018)] - Enhanced photocatalytic activity of WO3 nanoparticles loaded with carbon
摘要： Enhanced photocatalytic activity of WO3 was attempted by carbon nanodots (C-dots) loading. C-dots were prepared using citric acid and urea for enhancing photocatalytic activity of WO3. Physicochemical character of C-dots was studied by fluorescence spectrophotometry and for the modified WO3, evaluation was studied by using x-ray diffraction (XRD) and scanning electron microscope (SEM). Effect of varied citric acid: urea ratio to photocatalytic activity was evaluated in methylene blue photodegradation. Increasing photocatalytic activity was achived by higher intensity in blue color range that obtained by higher urea molar ratio. Kinetics of reaction obey pseudo-first order and pseudo-second order reaction. Reaction reached 80% MB degradation for an hour treatment for 50mM of methylene blue solution.
关键词： photocatalytic activity,methylene blue photodegradation,WO3 nanoparticles,carbon nanodots
更新于2025-11-14 15:15:56
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Conductive Films Based on Sandwich Structures of Carbon Nanotubes/Silver Nanowires for Stretchable Interconnects
摘要： A variety of conductive films made of a hybrid of two conductive nanomaterials have been used as stretchable electrodes or interconnectors, desirable for stretchable electronic devices. Their intrinsic stretchability of electrical conductivity would allow for accommodating mechanical strain to a certain extent under various deformations. However, few efforts have been made to enhance the interactions between two conductive components in a hybrid system. Herein, we reported new conductive films with tri-layer sandwich structures based on CNTs and AgNWs, encapsulated in silicone rubber, exhibited high stretchability along with insignificant piezoresistivity. They would be suitable to be stretchable interconnectors. A successive vacuum filtration method was used to stack the conductive components layer by layer. The effects of the stacking sequence and the interactions between layers on the stretchability and stability of electrical properties under mechanical deformations were studied. In the case of a tri-layer conductive film comprising two CNT outer layers and one AgNW central layer in presence of enhanced interfacial interactions, it showed exceptionally durability of withstanding repetitive deformations.
关键词： hybrid,silver nanowires,sandwich structure,carbon nanotubes,Stretchable electronics
更新于2025-11-14 15:15:56
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Ultraviolet to blue blocking and wavelength convertible films using carbon dots for interrupting eye damage caused by general lighting
摘要： Our eyes are regularly exposed to ultraviolet (UV) and blue light emitting diode (LED) light-based devices. However, the blue light induces macular degeneration, optic nerve crush, eye strain, and increases reactive oxygen species, which negatively influence eye-related cells (photoreceptor and retinal pigmented epithelial cells). UV light is also harmful to humans. It induces photokeratitis, cataract, and ocular surface squamous neoplasia. Here, we present carbon dot films with different carbon dot contents, prepared by a simple method. The films exhibit strong UV and blue light absorption. The transmittance of carbon dot films is >70% in the visible region (>500 nm). The UV light blocking ratio of commercial blue blocking filter and carbon dot film using UV LED chips is 94.1% and 95.9% (40 wt%), respectively. The blue light blocking ratio of commercial blue blocking filter and carbon dot film using blue LED chips is 10.2% and 82.3% (40 wt%), respectively. These results indicate that the prepared carbon dot films have a UV blocking rate similar to that of commercial blue blocking filters and a much better blue blocking rate than commercial blue blocking filters. Therefore, they can be effectively used as UV and blue blocking films in various applications.
关键词： White LED,Eye damage,UV blocking film,Carbon dot,blue blocking film
更新于2025-11-14 15:15:56