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Covalent Surface Modification Effects on Singlea??Walled Carbon Nanotubes for Targeted Sensing and Optical Imaging
摘要： Optical nanoscale technologies often implement covalent or noncovalent strategies for the modification of nanoparticles, whereby both functionalizations are leveraged for multimodal applications but can affect the intrinsic fluorescence of nanoparticles. Specifically, single-walled carbon nanotubes (SWCNTs) can enable real-time imaging and cellular delivery; however, the introduction of covalent SWCNT sidewall functionalizations often attenuates SWCNT fluorescence. Recent advances in SWCNT covalent functionalization chemistries preserve the SWCNT’s pristine graphitic lattice and intrinsic fluorescence, and here, such covalently functionalized SWCNTs maintain intrinsic fluorescence-based molecular recognition of neurotransmitter and protein analytes. The covalently modified SWCNT nanosensor preserves its fluorescence response towards its analyte for certain nanosensors, presumably dependent on the intermolecular interactions between SWCNTs or the steric hindrance introduced by the covalent functionalization that hinders noncovalent interactions with the SWCNT surface. These SWCNT nanosensors are further functionalized via their covalent handles with a targeting ligand, biotin, to self-assemble on passivated microscopy slides, and these dual-functionalized SWCNT materials are explored for future use in multiplexed sensing and imaging applications.
关键词： single-walled carbon nanotubes,biosensing,fluorescence,imaging,surface functionalization
更新于2025-09-16 10:30:52
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A Dual Role of Amino-functionalized Graphene Quantum Dots in NiOx Films for Efficient Inverted Flexible Perovskite Solar Cells
摘要： NiOx has been widely used as an effective hole transport material for inverted perovskite solar cells (PSCs), particularly flexible PSCs, owing to its low-temperature processing, low cost, and good electron blocking ability. However, the band structure alignment between low-temperature-processed NiOx and the perovskite layer is not satisfactory, resulting in reduced photovoltaic performance. Herein, we report a novel strategy to tune the NiOx hole transport layer for achieving high-performance flexible PSCs. Amino-functionalized graphene quantum dots (AGQDs) are employed in the NiOx film as a dual-role additive. On the one hand, the added AGQDs can provide abundant N atoms at the modified NiOx layer surface to enhance the crystallization of the perovskite film by a Lewis base-acid interaction. On the other hand, the AGQDs can optimize the band structure alignment between the NiOx and perovskite layers, facilitating hole extraction at the NiOx/perovskite interface. As a result, the inverted flexible PSCs exhibit a champion efficiency of 18.10%, which is comparable to the values reported for the current state-of-the-art inverted flexible PSCs. In addition to good air stability, our best flexible device has excellent mechanical stability, retaining 88% of its initial efficiency after continuously bending 1000 times. This new strategy highlights a promising way to enhance the performance of inverted flexible PSCs.
关键词： flexible,amino functionalization,graphene quantum dots,NiO,inverted perovskite solar cells
更新于2025-09-16 10:30:52
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Effect of Photocrosslinking of D‐A Thiophene Copolymers on the Performance of Single‐Material Solar Cells
摘要： Side-chain C60-fullerene functionalized alkylthiophene copolymers with different regioregularity and fullerene content are successfully synthesized using a simple and straightforward post-polymerization functionalization procedure based on a Grignard coupling reaction. The products are employed as single materials in photoactive layers of organic photovoltaic solar cells. The use of double-cable polymers allows an enhanced control on the nano-morphology of the active blend, reducing the phase-segregation phenomena as well as the macroscale separation between the electron acceptor and donor components. With the insertion of a thin layer of gold nanoparticles between buffer and active layer of the cells, a conversion efficiency of 5.68% is obtained. Moreover, an increased stability over time is achieved when the copolymers are photocrosslinked immediately after the annealing procedure, leading to acceptable efficiencies even after 80 h of accelerated ageing, a key feature for widespread applicability of the prepared devices.
关键词： conjugated polymers,metathesis,functionalization of polymers,fullerenes
更新于2025-09-12 10:27:22
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Hydrophilic to ultrahydrophobic transition of Al 7075 by affordable ns fiber laser and vacuum processing
摘要： A lot of research efforts have been invested in the fabrication of superhydrophobic surfaces in recent years due to many protentional applications in science and industry including anti-icing, self-cleaning and anti-corrosive surfaces. Laser as a non-polluting, precise and flexible tool can be applied to replicate surface microstructures of extremely water repellent lotus leave surface. In this study, a common nanosecond laser source is used to fabricate a super/ultrahydrophobic surfaces with different microstructure designs, contact angles above 170° and sliding angles below 5°. The freshly processed surface is hydrophilic and becomes hydrophobic and superhydrophobic in a certain time period, which could be dramatically reduced by storing samples in high vacuum. The transformation in wetting properties are analysed with respect to surface geometry and surface chemistry.
关键词： Surface functionalization,fiber laser,vacuum processing,ultrahydrophobicity
更新于2025-09-12 10:27:22
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The influence of edge structure on the optoelectronic properties of Si <sub/>2</sub> BN quantum dot
摘要： In recent work, we have investigated the electronic and optical properties of pristine and functionalized Si2BN quantum dots (QDs) using first-principles calculations. Due to the edge functionalization, Si2BN QDs have binding energies of ?0.96 eV and ?2.08 eV per hydrogen atom for the adsorption of single and double hydrogen atoms, respectively. These results reveal the stability and the bonding nature of hydrogen at the edges of Si2BN QD. In particular, the charge transfer between hydrogen and other atoms is explicitly increased. The electronic band structure of pristine Si2BN QD shows a metallic behavior with a finite number of electronic states in the density of states at the Fermi level. The frequency-dependent optical properties, such as refractive index, extinction coefficient, absorption coefficient, electron energy loss spectra, and reflectivity, are computed for both the parallel and perpendicular components of electric field polarization. The higher absorption was found in the infrared regime. The present study shows that the functionalization of Si2BN QD by two hydrogen atoms is energetically stable. It offers a promising application of Si2BN QD, which can be used in optical nanodevices such as photodetectors and biomedical imagination.
关键词： optical properties,Si2BN quantum dot,first-principles calculations,metallic behavior,electronic properties,hydrogen functionalization,infrared absorption,optical nanodevices
更新于2025-09-12 10:27:22
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Surface functionalization under water using picosecond and femtosecond laser pulses – first observations and novel effects
摘要： Functionalization by changing the topography of workpiece surfaces is interesting for many applications. Lasers – especially ultrashort pulse lasers – are flexible tools for this kind of tasks. Besides deterministic structures they allow for processing surfaces in a way that stochastic structures appear. Ripple and spike structures can be fabricated in air. In liquids, however, there are only a few investigations and many open questions. The idea of this paper is to check how water in contact to the workpiece surface affects femtosecond laser surface processing and what kind of structures appear. Results obtained with a picosecond laser are presented for comparison.
关键词： ultrashort pulse laser,surface functionalization,spike structures,material processing in liquids
更新于2025-09-12 10:27:22
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3D, covalent and noncovalent hybrid materials based on 3-phenylcoumarin derivatives and single walled carbon nanotubes as gas sensing layers
摘要： In this work, the effect of different types of functionalization of single walled carbon nanotubes (SWCNT) with 3-phenylcoumarin derivatives on the chemiresistive sensor response to ammonia (10–50 ppm) was studied. Covalent functionalization of SWCNT was performed according to the Huisgen reaction of azide-alkyne 1,3-dipolar cycloaddition between mono alkyne-substituted 3-phenylcoumarin and single walled nanotubes modified by azide groups. Covalent functionalization was shown by IR- and X-ray photoelectron spectroscopy. To obtain the 3D hybrid material, the dialkyne functionalized 3-phenylcoumarin molecules were used as linkers between nanotubes. Third hybrid material was prepared by noncovalent functionalization of SWCNT, namely by adsorption of 7-propinyloxy-3-(p-propinyloxyphenyl)coumarin on SWCNT surface. It was shown that the 3D hybrid and the hybrid obtained by covalent functionalization exhibit 2 and 4 times higher sensor responses to ammonia compared to noncovalently functionalized SWCNT. The value of sensor response is in good correlation with the degree of functionalization of SWCNTs with coumarin molecules.
关键词： Non covalent functionalization,3D carbon nanostructures,Covalent functionalization,Carbon nanomaterials,Ammonia sensor,Coumarin
更新于2025-09-11 14:15:04
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Effects of laser processing conditions on wettability and proliferation of Saos-2 cells on CoCrMo alloy surfaces
摘要： Any processing disturbances in laser surface texturing (LST) could compromise the resulting surface topography and their desired functional response. Disturbances such as focal plane offsets and beam incident angle variations are always present in LST processing of 3D parts and can affect the surface morphology. In this research the effects of these laser processing disturbances in producing laser induced surface structures (LIPSS) on CoCrMo alloy substrates were investigated. In particular, these two disturbances were considered as laser processing variables to determine their effects on functional responses of LIPSS treated surfaces, i.e. surface wettability and the proliferation of Saos-2 osteoblast-like cells were evaluated. It was found that the changes of laser processing conditions led to a decrease in surface wettability and Saos-2 cells proliferation. In addition, a correlation between surface wettability and cell proliferation on LIPSS treated surface was identified and conclusions made about the effects of investigated process disturbances on the functional response of LIPSS treated CoCrMo substrates.
关键词： cobalt chrome molybdenum,surface functionalization,laser induced periodic surface structures,osseointegration,laser surface texturing
更新于2025-09-11 14:15:04
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[Laser Institute of America ICALEO? 2016: 35th International Congress on Applications of Lasers & Electro-Optics - San Diego, California, USA (October 16–20, 2016)] International Congress on Applications of Lasers & Electro-Optics - Selective femtosecond laser ablation of graphene for its micro-patterning
摘要： Due to the outstanding electrical properties of graphene, the demand of its clean and well-defined micro-structures for diverse applications has increased. However, such micro-structured graphene is difficult due to handling and machining problems. Femtosecond lasers are versatile tools for controlled ablation and resulting patterning process. In this paper, we present the selective ablation and functionalization of monolayers of graphene on 300 nm thick thermally grown silicon dioxide on silicon substrates with a Ti:sapphire laser (λ = 800 nm, τ = 40 fs). Investigations were performed on the micro-patterns in graphene ablated by the laser in the fluence range of 0.9-2.2 J/cm2. Just below the ablation threshold functionalization of the graphene layer was obtained. The resolution of the patterning was in the range of a few micrometers. In order to study the effect of oxidation of graphene at the ablation rim, the experiments were conducted both under ambient and inert gas atmosphere conditions. The morphology of the irradiated region of graphene was evaluated with optical microscopy, scanning electron microscopy and atomic force microscopy. With Raman spectroscopy the complete removal of graphene was ascertained. Finally, we find that femtosecond laser ablation is a promising method for direct writing of micro-patterns in graphene monolayers for various potential applications, e.g. for electrodes of thin film transistors.
关键词： selective ablation,functionalization,femtosecond laser ablation,micro-patterning,graphene
更新于2025-09-11 14:15:04
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Chemistry of Carbon Nanostructures || 2. Controlled Functionalization of Graphene by Oxo-addends
摘要： The single carbon layer graphene and especially its oxidized derivatives, such as graphene oxide (GO), are in the focus of research that started already 150 years ago [1–6]. GO is a collective term for various single layers of graphene (with lattice defects) functionalized by oxo-addends. The type of oxo-groups is not defined, but epoxy and hydroxyl groups dominate the structure in addition to in-plane lattice defects on the percent scale. Those defects are rarely considered in chemical functionalization approaches and it is impossible to distinguish between functionalization of surface oxo-groups and in-plane oxo-groups. This chapter focuses on functionalized derivatives of graphene with an almost intact carbon framework, termed “oxo-functionalized graphene” (oxo-G1, index indicates the number of layers). Avoiding in-plane defects further allows the development of a controlled chemistry of graphene with oxo-addends. However, general approaches of conventional GO chemistry are summarized in a separate section.
关键词： graphene oxide,oxo-functionalized graphene,functionalization
更新于2025-09-11 14:15:04