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An Effective Approach to Improve the Photocatalytic Activity of Graphitic Carbon Nitride via Hydroxyl Surface Modification
摘要： In this work, we have developed a hydrothermal method to modify g-C3N4 with hydroxyl surface modification. Modified g-C3N4 has exhibited higher photocatalytic activity in the removal of phenolic compounds under visible light. The improvement may be due to the following merits: (1) Tuning of the hydrophobic surface of g-C3N4 to be hydrophilic; (2) improved adsorption energy, and (3) narrowed band gap for g-C3N4 after hydroxyl surface modification. This method is easy-to-operate, very effective in adding hydroxyl groups on the surface of C3N4, and may be extended to other systems to promote their photocatalytic activities in water treatment.
关键词： water treatment,photocatalysis,hydroxyl,surface modification,g-C3N4
更新于2025-09-23 15:22:29
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Hyperspectral and Color Imaging of Solvent Vapor Sorption Into Porous Silicon
摘要： A porous silicon thin film photonic crystal (rugate) sample with both a radial gradient in the rugate reflectance band wavelength and two spatially separated pore-wall surface chemistries (methylated and oxidized) was monitored by hyperspectral and color imaging while it was dosed with vapors of acetone, ethanol, heptane, 2-propanol, and toluene at concentrations ranging from 100 to 3,000 mg m?3. The shift in the wavelength of the rugate reflectance band maximum at each position along a transect across the two surface chemistries, as derived from the hyperspectral imaging, could discriminate between the different solvents and concentrations of solvents, while the change in hue derived from the color camera data along an analogous transect did not provide discrimination. The discrimination between solvents was mainly due to the two different surface chemistries, and the gradient associated with the change in the rugate reflectance band wavelength did not affect the selectivity significantly. There was spatial variability in the spectral and color responses along the transect independent of the overall rugate reflectance band wavelength gradient and pore-wall surface chemistries, and this was attributed to factors such as the presence of striations in the silicon wafer from which the porous silicon was prepared.
关键词： sensor,porous silicon,hyperspectral imaging,surface modification,vapor sensing
更新于2025-09-23 15:22:29
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Surface Functionalisation of Upconversion Nanoparticles with Different Moieties for Biomedical Applications
摘要： Lanthanide ion-doped upconversion nanoparticles (UCNPs) that can convert low-energy infrared photons into high-energy visible and ultraviolet photons, are becoming highly sought-after for advanced biomedical and biophotonics applications. Their unique luminescent properties enable UCNPs to be applied for diagnosis, including biolabeling, biosensing, bioimaging, and multiple imaging modality, as well as therapeutic treatments including photothermal and photodynamic therapy, bio-reductive chemotherapy and drug delivery. For the employment of the inorganic nanomaterials into biological environments, it is critical to bridge the gap in between nanoparticles and biomolecules via surface modifications and subsequent functionalisation. This work reviews the various ways to surface modify and functionalise UCNPs so as to impart different functional molecular groups to the UCNPs surfaces for a broad range of applications in biomedical areas. We discussed commonly used base functionalities, including carboxyl, amino and thiol moieties that are typically imparted to UCNP surfaces so as to provide further functional capacity.
关键词： lanthanide,functionalisation,silanisation,surface modification,ligand engineering,nanoparticles,upconversion
更新于2025-09-23 15:22:29
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Polydopamine-Coated Gold Core/Hollow Mesoporous Silica Shell Particles as a Nanoplatform for Multimode Imaging and Photothermal Therapy of Tumors
摘要： It is highly desirable to develop a new hybrid nanoplatform that integrates diagnosis and treatment elements for effective theranostics of tumors. Herein, we have skillfully designed a nanoplatform of polydopamine (PDA)-coated and perfluorohexane (PFH)-filled gold core/hollow mesoporous silica shell (Au@mSiO2-PFH-PDA, ASPP for short) particles for photoacoustic (PA)/ultrasound (US)/computed tomography (CT)/thermal imaging and photothermal therapy (PTT) of tumors. In this work, we first synthesized Au seed particles with a diameter of 15.8 nm using a sodium citrate reduction method, and coated Au seeds with polyvinylpyrrolidone for further growth of solid silica shell/mesoporous silica shell onto the Au seeds. After treatment via selective etching to remove solid silica shell, amination of surface of the particles, and filling of PFH into the internal cavity of the spheres with a diameter of 182.1 nm, PDA coating was performed to render the particles with an external shell thickness of 15.1 nm. The formed hybrid particles with a size of 212.2 nm are colloidally stable and exhibit good cytocompatibility, and display excellent PA/US/CT/thermal imaging property due to the co-presence of PDA, PFH, and Au nanoparticles. Furthermore, the PDA coating renders the platform with a photothermal conversion efficiency of 61.2%, enabling effective photothermal ablation of cancer cells in vitro and a xenografted 4T1 tumor model in vivo under irradiation with an 808 nm laser. More importantly, in the primary 4T1 tumor model, intratumoral injection of the ASPP and irradiation with an 808 nm laser can also completely inhibit the occurrence lung metastasis induced by the 4T1 tumor. The as-prepared hybrid nanoplatform may hold a great promise to be adopted for multimode imaging and PTT of tumors and inhibition of tumor metastasis.
关键词： Tumor metastasis inhibition,Multimode imaging,Photothermal therapy,Polydopamine NPs,Hollow mesoporous silica,Surface modification
更新于2025-09-23 15:22:29
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The flower-like heterostructured Fe2O3/MoS2 coated by amorphous Si-Oxyhydroxides: An effective surface modification method for sulfide photocatalysts in photo-Fenton reaction
摘要： The semiconductor photocatalytic technology is an important approach for solving the energy and environmental problems by only harnessing solar energy. Herein, we employ a facile hydrothermal method to prepare 3D flower-like Fe2O3/MoS2 heterostructures, which perform a high efficient photocatalytic property on photodegrading 20 mg/L methyl blue (MB) solution within 20 min, over 10 times of bare Fe2O3 nanoparticles. In addition, we first propose a surface modification method using amorphous Si-oxyhydroxides (SiOxH) as coating layer to protect the sulfide photocatalysts from corrosion in photo-Fenton reaction. As a result, the SiOxH-Fe2O3/MoS2 nanocomposites show good stability and high efficient decomposition behavior in photo-Fenton reaction, while the MoS2 nanosheets of as-prepared Fe2O3/MoS2 heterostructures without SiOxH modification have been almost all corroded away.
关键词： Photocatalyst,Heterostructure,Characterization,Surface modification.
更新于2025-09-23 15:22:29
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Synthesis and characterization of nickel free titanium–hydroxyapatite composite coating over Nitinol surface through in-situ laser cladding and alloying
摘要： In this study, a high power fibre laser was used to synthesize titanium hydroxyapatite composite coating over biomedical-grade Nitinol surface through laser in-situ formation, cladding and alloying processes. The laser fluence is varied in the range of 2 kJ/cm2 to 8 kJ/cm2 in view of establishing a relationship between various in-situ phase-formation characteristics along with the rate of diffusion of the base material in the cladding zone with molten pool temperature. The alloying with base Nitinol material and subsequent diffusion of titanium to the in-situ formed calcium phosphate cladding layer are observed in the samples treated with laser fluence of 4 kJ/cm2 or above. Double layer configuration of the solidified molten pool is mostly found in all the cladding samples. At the fluence of 6 kJ/cm2 or above, the top layer primarily comprises segregated titanium-hydroxyapatite phase along with diffusion of titanium from the base material. Whereas, the bottom part of the molten pool is dominated with titanium-rich nickel–titanium intermetallic reinforced with nano particles. The steady-state variations of calcium and elemental presence of titanium through the cladding cross-section along with no nickel or oxide presence are confirmed through EDS line scans. The spherical and lamellar structures of formation of titanium-hydroxyapatite on the top surface also help to improve the overall corrosion resistance properties as compared to the bare surface. The modulus of elasticity is controlled by the variation of the top layer and intermediate layer composition and thickness, which varies with laser fluence. It falls in the range of 6–30 GPa which is similar to natural bone. Thus this nickel-free alloying and cladding layer of titanium-hydroxyapatite can serve as one of the potential candidates for use as a coating over the load bearing Nitinol implants to arrest the nickel release phenomena.
关键词： Titanium–calcium coating,Biocompatible functional coating,Hydroxyapatite,Nitinol surface modification,Laser cladding and alloying
更新于2025-09-23 15:22:29
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DNA origami deposition on native and passivated molybdenum disulfide substrates
摘要： Maintaining the structural fidelity of DNA origami structures on substrates is a prerequisite for the successful fabrication of hybrid DNA origami/semiconductor-based biomedical sensor devices. Molybdenum disulfide (MoS2) is an ideal substrate for such future sensors due to its exceptional electrical, mechanical and structural properties. In this work, we performed the first investigations into the interaction of DNA origami with the MoS2 surface. In contrast to the structure-preserving interaction of DNA origami with mica, another atomically flat surface, it was observed that DNA origami structures rapidly lose their structural integrity upon interaction with MoS2. In a further series of studies, pyrene and 1-pyrenemethylamine, were evaluated as surface modifications which might mitigate this effect. While both species were found to form adsorption layers on MoS2 via physisorption, 1-pyrenemethylamine serves as a better protective agent and preserves the structures for significantly longer times. These findings will be beneficial for the fabrication of future DNA origami/MoS2 hybrid electronic structures.
关键词： atomic force microscopy (AFM),molybdenum disulfide (MoS2),1-pyrenemethylamine,pyrene,DNA origami,surface modification
更新于2025-09-23 15:22:29
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CFRP laser texturing to increase the adhesive bonding: morphological analysis of treated surfaces
摘要： Surface roughness of the adherends represents an important factor for manufacturing a reliable bonded joint in structural applications. In case of bonding of parts in carbon fibre reinforced polymer (CFRP), an increase of roughness parameters can be obtained with various techniques. In this paper, the morphology obtained from a CO2 laser texturing on CFRP laminates were investigated. CFRP laminates were manufactured and subjected to laser texturing with various densities. In particular, the densities of treatment have been defined as a function of the grid dimensions of the texture. Subsequently, non-contact measurements were carried out to evaluate the evolution of the surface roughness parameters as a function of the density of the laser treatment. Results showed a strong correlation between surface roughness and density of treatment. In conclusion, these results were compared with experimental tests, which showed that the mechanical performance for ENF bonded joints was limited only by the flexural mechanical resistance of the CFRP adherends. As a result of this work, the developed laser texturing approach is potentially able to increase the mechanical resistance in the function of the real local load acting on the complex bonded joint, optimizing time and cost process.
关键词： surface modification,surface roughness/morphology,Composites,adhesion by mechanical interlocking
更新于2025-09-23 15:21:01
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Gallium arsenide waveguides as a platform for direct mid-infrared vibrational spectroscopy
摘要： During recent years, mid-infrared (MIR) spectroscopy has matured into a versatile and powerful sensing tool for a wide variety of analytical sensing tasks. Attenuated total reflection (ATR) techniques have gained increased interest due to their potential to perform non-destructive sensing tasks close to real time. In ATR, the essential component is the sampling interface, i.e., the ATR waveguide and its material properties interfacing the sample with the evanescent field ensuring efficient photon-molecule interaction. Gallium arsenide (GaAs) is a versatile alternative material vs. commonly used ATR waveguide materials including but not limited to silicon, zinc selenide, and diamond. GaAs-based internal reflection elements (IREs) are a new generation of semiconductor-based waveguides and are herein used for the first time in direct spectroscopic applications combined with conventional Fourier transform infrared (FT-IR) spectroscopy. Next to the characterization of the ATR waveguide, exemplary surface reactions were monitored, and trace-level analyte detection via signal amplification taking advantage of surface-enhanced infrared absorption (SEIRA) effects was demonstrated. As an example of real-world relevance, the mycotoxin aflatoxin B1 (AFB1) was used as a model analyte in food and feed safety analysis.
关键词： Mid-infrared chem/biosensor,Surface modification,Gallium arsenide,Self-assembled monolayers,Evanescent field absorption,Surface-enhanced infrared absorption
更新于2025-09-23 15:21:01
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Bright CsPbI <sub/>3</sub> Perovskite Quantum Dot Light-Emitting Diodes with Top-Emitting Structure and a Low Efficiency Roll-Off Realized by Applying Zirconium Acetylacetonate Surface Modification
摘要： Zirconium acetylacetonate used as a co-precursor in the synthesis of CsPbI3 quantum dots (QDs) increased their photoluminescence quantum efficiency to values over 90%. The top-emitting device structure on a Si substrate with high thermal conductivity (to better dissipate Joule heat generated at high current density) was designed to improve the light extraction efficiency making use of a strong microcavity resonance between the bottom and top electrodes. As a result of these improvements, light-emitting diodes (LEDs) utilizing Zr-modified CsPbI3 QDs with an electroluminescence at 686 nm showed external quantum efficiency (EQE) of 13.7% at a current density of 108 mA cm?2, which was combined with low efficiency roll-off (maintaining an EQE of 12.5% at a high current density of 500 mA cm?2) and a high luminance of 14 725 cd m?2, and the stability of the devices being repeatedly lit (cycled on and off at high drive current density) has been greatly enhanced.
关键词： CsPbI3 perovskite quantum dots,top-emitting light-emitting diodes,surface modification,zirconium acetylacetonate,efficiency roll-off
更新于2025-09-23 15:21:01