- 标题
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- 实验方案
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Multifunctional N,S co-doped carbon dots for sensitive probing of temperature, ferric ion, and methotrexate
摘要： In this paper, we have presented a facile method to fabricate nitrogen and sulfur co-doped carbon dots (N,S-CDs) for blood methotrexate (MTX) sensing applications. The N,S-CDs with quantum yield up to 75% were obtained by one-step hydrothermal carbonization, using reduced glutathione and citric acid as the precursors. With this approach, the formation and the surface passivation of N,S-CDs were carried out simultaneously, resulting in intrinsic fluorescence emission. Owing to their pronounced temperature dependence of the fluorescence emission spectra, resultant N,S-CDs can work as versatile nanothermometry devices by taking advantage of the temperature sensitivity of their emission intensity. In addition, the obtained N,S-CDs facilitated high selectivity detection of Fe3+ ions with a detection limit as low as 0.31 μM and a wide linear range from 3.33 to 99.90 μM. More importantly, the added MTX selectively led to the fluorescence quenching of the N,S-CDs. Such fluorescence responses were used for well quantifying MTX in the range of 2.93 to 117.40 μM, and the detection limit was down to 0.95 μM. Due to Binert^ surface, the N,S-CDs well resisted the interferences from various biomolecules and exhibited excellent selectivity. The proposed sensing system was successfully used for the assay of MTX in human plasma. Due to simplicity, sensitivity, selectivity, and low cost, it exhibits great promise as a practical platform for MTX sensing in biological samples.
关键词： Hydrothermal carbonization,Doped carbon dots,Excitation-independent emission,Multifunctional probe,Methotrexate,Surface passivation
更新于2025-11-19 16:46:39
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Polyimide-TiO2 nanocomposites and their corresponding membranes: Synthesis, characterization, and gas separation applications
摘要： In this work at firstly a new class of polyimide/TiO2 (PI/TiO2) composites containing amino acid (Methionine) and benzimidazole fractions in the structure with chemical bonds between the polyimide and TiO2 network has been synthesized by the sol-gel reaction and characterized and then secondly carbon (C) membranes were prepared by carbonization of PI/TiO2 at different temperatures under vacuum and nitrogen flow. Carbonization temperature was critical in the modification of membrane structure. At the same temperature, the carbon membranes fabricated under nitrogen atmosphere had higher gas permeations than those fabricated under vacuum. With the introduction of the TiO2, there was no significant enhancement of the gas separation in the resulting PI/TiO2 composite membranes over the PI membrane, which still suffered a "trade-off" relationship between permeability and selectivity. However, the derived C/PI/TiO2 composite membranes exhibited better gas separation properties. The C/PI/TiO2 15% composite membrane produced the highest permeations of 650.47, 520.56, 187.92 and 115.22 GPU for He, CO2, O2 and N2, respectively. The bionanocomposites were analyzed for antibacterial activity against Gram-positive and Gram-negative bacteria. The results indicated that the synthesized bionanocomposites is effective against all of the studied bacteria, and its effectiveness is higher for Pseudomonas aeruginosa.
关键词： Polyimide,Composite membranes,Carbonization,TiO2,Gas permeations
更新于2025-09-23 15:23:52
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Highly Linear and Stable Flexible Temperature Sensors Based on Lasera??Induced Carbonization of Polyimide Substrates for Personal Mobile Monitoring
摘要： Wearable on-skin electronic devices that can monitor temperature in real time are of significant interest for personalized mobile health monitoring. Here, a flexible temperature sensor directly patterned by laser-induced carbonization on Kapton polyimide films integrated with flexible printed circuit boards is reported. The proposed sensor design possessing high resistance values exhibits high-linear and stable response to temperatures when integrated with flexible printed circuit boards (FPCBs) to enable continuous monitoring. The anisotropic conductive film bonding technique is used to obtain the stable real-time monitoring data under various complex environments. The sensor integration with a wearable patch based FPCB establishes conformal contacts with human skin and allows wireless sensing capabilities smoothly in real time. This kind of approach can enable multifunctional sensors to be directly laser patterned on FPCBs without any additional interfacing.
关键词： real-time monitoring,FPCB,laser-induced carbonization,temperature sensors,biomedical devices
更新于2025-09-23 15:21:01
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Improved conductivity of carbonized polyimide by CO <sub/>2</sub> laser graphitization
摘要： Direct laser writing (DLW) is a fast and cost-effective technique for printing conductive structures on flexible substrates such as polyimide (PI) by the conversion of insulative PI to conductive carbon. However, the conductivity (B103 S m?1) obtained by this method needs to be improved to compete with ink-jet printing of carbon-based materials. The reason behind the low conductivity achieved by the DLW process is due to the crystallinity and hybridization of bonding in carbonaceous structures. In this work, the DLW process has been implemented in two steps: the first step called carbonization was performed by writing pulsed CO2 laser on PI to form tracks which consist of amorphous tetrahedral carbon (a mixture of sp2 and sp3 hybridized carbon) having intrinsically low conductivity. The second step called graphitization is overwriting of the laser on the pre-carbonized tracks to convert sp3 hybridized bonds to sp2 hybridized bonds by the process called laser graphitization. The conductivity of tracks carbonized at (0.21 ± 0.02) W and fluence (3.31 ± 0.32) × 103 mJ cm?2 at a repetition rate of 0.1 kHz was 56.1 ± 3.1 S m?1 which increased to 146.7 ± 5.1 S m?1 upon overwriting with the laser at (0.50 ± 0.03) W and fluence (7.88 ± 0.47) × 103 mJ cm?2 at the same repetition rate. The photothermal process of carbonization and graphitization is modeled for the DLW process and the threshold power of both the processes is calculated and validated by Raman spectroscopy. Improved conductivity achieved by detailed understanding of the laser and material parameters involved in this transformation enables process optimization leading to future applications in scalable manufacturing of flexible bio-sensors and electrochemical energy storage devices.
关键词： Direct laser writing,carbonization,graphitization,CO2 laser,polyimide,conductivity
更新于2025-09-19 17:13:59
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High-performance solar vapor generation of Ni/carbon nanomaterials by controlled carbonization of waste polypropylene; ??ˉ??§?￠3????o????è???????ˉ????¤?é??/?￠3?o3?±3????????¨?o?é????????è???°?è????￠;
摘要： Solar vapor generation is emerging as a promising technology using solar energy for various applications including desalination and freshwater production. However, from the viewpoints of industrial and academic research, it remains challenging to prepare low-cost and high-efficiency photothermal materials. In this work, we report the controlled carbonization of polypropylene (PP) using NiO and poly(ionic liquid) (PIL) as combined catalysts to prepare a Ni/carbon nanomaterial (Ni/CNM). The morphology and textural property of Ni/CNM are modulated by adding a trace amount of PIL. Ni/CNM consists of cup-stacked carbon nanotubes (CS-CNTs) and pear-shaped metallic Ni nanoparticles. Due to the synergistic effect of Ni and CS-CNTs in solar absorption, Ni/CNM possesses an excellent property of photothermal conversion. Meanwhile, Ni/CNM with a high specific surface area and rich micro-/meso-/macropores constructs a three-dimensional (3D) porous network for efficient water supply and vapor channels. Thanks to high solar absorption, fast water transport, and low thermal conductivity, Ni/CNM exhibits a high water evaporation rate of 1.67 kg m?2 h?1, a solar-to-vapor conversion efficiency of 94.9%, and an excellent stability for 10 cycles. It also works well when converting dye-containing water, seawater, and oil/water emulsion into healthy drinkable water. The metallic ion removal efficiency of seawater is 99.99%, and the dye removal efficiency is >99.9%. More importantly, it prevails over the-state-of-art carbon-based photothermal materials in solar energy-driven vapor generation. This work not only proposes a new sustainable approach to convert waste polymers into advanced metal/carbon hybrids, but also contributes to the fields of solar energy utilization and seawater desalination.
关键词： synergistic effect,waste polymer,solar vapor generation,Ni/carbon nanomaterial,controlled carbonization,photothermal materials
更新于2025-09-19 17:13:59
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Glucose-derived porous carbon as a highly efficient and low-cost counter electrode for quantum dot-sensitized solar cells
摘要： Biomass-derived porous carbon is widely used in supercapacitors, carbon dioxide capture and lithium–sulfur batteries owing to its advantages such as wide sources, low cost and good stability. However, it is rarely used in quantum dot-sensitized solar cells (QDSCs). Here, glucose-derived porous carbon was obtained by hydrothermal carbonization followed with high-temperature KOH activation, and employed as an efficient counter electrode (CE) for QDSCs. The CV, EIS and Tafel-polarization analysis showed that porous carbon exhibits excellent catalytic activity for reduction of Sn2?. The CE based on porous carbon activated at 900 °C (C900) presents best performance with interface charge transfer resistance (Rct) of 2.4 Ω cm2 due to the synergy between high graphitization degree and large specific surface area. The power conversion efficiency (PCE) of the QDSCs assembled with a CdS/CdSe sensitized TiO2 photoanode and the C900 CE is up to 5.61% under one sun illumination. The excellent catalytic activity of C900 is attributed to its large specific surface area and porous structure and high degree graphitization. This suggests that glucose-derived porous carbon can become a potential low-cost and efficient CE material for QDSCs.
关键词： biomass-derived porous carbon,KOH activation,quantum dot-sensitized solar cells,hydrothermal carbonization,counter electrode,glucose
更新于2025-09-19 17:13:59
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New Strategy to Achieve Laser Direct Writing of Polymers: Fabrication of the Color-Changing Microcapsule with Core-Shell Structure
摘要： This paper proposed an efficient and environmentally friendly strategy to prepare a new color-changing microcapsule with core-shell structure for laser direct writing of polymers, and only the physical melt blending of polymers was employed. The laser absorber (SnO2) and the easily carbonized polymer (PC) were designed as the “core” and the “shell” of the microcapsule, respectively. The microcapsules were in situ formed during melt blending. SEM, TEM, and EDS confirmed the successful preparation of SnO2/PC microcapsules with core-shell structure. Its average diameter was 2.2 μm, and the “shell” thickness was 0.21?0.24 μm. As expected, this SnO2/PC microcapsule endowed polymers with an outstanding performance of NIR laser direct writing. The Raman spectroscopy and XPS indicated that the color change ascribed to the polymer carbonization due to the instantaneous high temperature caused by the SnO2 absorption of NIR laser energy. Optical microscopy observed a thick carbonization layer of 234 μm. Moreover, Raman depth imaging revealed the carbonization distribution, confirming that the amorphous carbon produced by the carbonization of the PC “shell” is the key factor of SnO2/PC microcapsules to provide polymers an outstanding performance of laser direct writing. This color-changing microcapsule has no selectivity to polymers due to providing a black color source (the carbonization of PC) itself, ensuring the high contrast and precision of patterns or texts after laser direct writing for all general-purpose polymers. We believe that this novel strategy to achieve laser direct writing of polymers will have broad application prospects.
关键词： microcapsule,core-shell structure,carbonization,polymer,laser direct writing,near-infrared pulsed laser
更新于2025-09-16 10:30:52
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MoC/MnO composite materials as high efficient and stable counter electrode catalysts for dye-sensitized solar cells
摘要： MoC/MnO composite materials have been easily synthesized via a two-step hydrothermal and one-step carbonization method and used as counter electrode catalysts in DSSCs for the first time. The as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). And their electrocatalytic properties were also thoroughly studied by electrochemical impedance spectroscopy (EIS), Tafel polarization and so on. It is found that the electrocatalytic properties of the MoC/MnO CEs can be greatly enhanced. After optimizing the molar ratio of MoO3 precursor and KMnO4, the as-obtained MoC/MnO-0.25 CE has superior electrocatalytic ability, low charge transfer resistance and high incident photon-to-current conversion efficiency (IPCE). And the power conversion efficiency of the DSSC based on the MoC/MnO-0.25 CE is up to 8.00%, better than that of the DSSC used standard Pt CE (7.36%) in the same test environment, meanwhile the MoC/MnO-0.25 CE also has good electrochemical stability in the iodine-based electrolyte, which shows a promising candidate to replace Pt for DSSCs.
关键词： MoC/MnO composite materials,carbonization method,hydrothermal method,counter electrode catalysts,dye-sensitized solar cells
更新于2025-09-12 10:27:22
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Microcontact Printing with Laser Direct Writing Carbonization for Facile Fabrication of Carbon‐Based Ultrathin Disk Arrays and Ordered Holey Films
摘要： A nanometer-thick carbon film with a highly ordered pattern structure is very useful in a variety of applications. However, its large-scale, high-throughput, and low-cost fabrication is still a great challenge. Herein, microcontact printing (μCP) and direct laser writing carbonization (DLWc) are combined to develop a novel method that enables ease of fabrication of nanometer-thick and regularly patterned carbon disk arrays (CDAs) and holey carbon films (HCFs) from a pyromellitic dianhydride-oxydianiline-based polyamic acid (PAA) solution. The effect of PAA concentration and pillar lattice structure of the polydimethyl siloxane stamp are systematically studied for their influence on the geometrical parameter, surface morphology, and chemical structure of the finally achieved CDAs and HCFs. Within the PAA concentration being investigated, the averaged thickness of CDAs and HCFs can be tailored in a range from a few tens to a few hundred of nanometers. The μCP+DLWc-enabled electrically conductive CDAs and HCFs possess the characteristics of ease-of-fabrication, nanometer-thickness, highly regular and controlled patterns and structures, and the ability to form on both hard and soft substrates, which imparts usefulness in electronics, photonics, energy storage, catalysis, tissue engineering, as well as physical, chemical, and bio-sensing applications.
关键词： direct laser writing carbonization,holey carbon films,microcontact printing,carbon disk arrays
更新于2025-09-11 14:15:04
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Carbon quantum dots derived by direct carbonization of carbonaceous microcrystals in mesophase pitch
摘要： Aggregation of the central aromatic ring system of asphaltene molecules due to π–π interaction can lead to the formation of carbon quantum dots (CQDs). However, to date, such a roadmap has not been demonstrated. Here, we present a simple approach to the synthesis of CQDs by direct carbonization of dispersed carbonaceous microcrystals in mesophase pitch. The size of the as-prepared CQDs is modulated by adjusting the nucleation temperature for mesophase formation. Due to the oxygen-free character, the CQDs exhibit excitation-independent fluorescent behavior with a quantum yield up to 87%. The CQDs were successfully applied to fluorescent detection of Fe3+ ions with good specificity and sensitivity. Our results not only provide a scalable production of CQDs at low cost, but also give valuable clues to understand the solidification of asphaltene at nanoscale.
关键词： Fe3+ ions,carbonization,mesophase pitch,fluorescent detection,carbon quantum dots
更新于2025-09-11 14:15:04