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Tuning the Functional Groups on Carbon Nanodots and Antioxidant Studies
摘要： Carbon nanodots (CNDs) have shown good antioxidant capabilities by scavenging oxidant free radicals such as diphenyl-1-picrylhydrazyl radical (DPPH?) and reactive oxygen species. While some studies suggest that the antioxidation activities associate to the proton donor role of surface active groups like carboxyl groups (–COOH), it is unclear how exactly the extent of oxidant scavenging potential and its related mechanisms are influenced by functional groups on CNDs’ surfaces. In this work, carboxyl and the amino functional groups on CNDs’ surfaces are modified to investigate the individual influence of intermolecular interactions with DPPH? free radical by UV-Vis spectroscopy and electrochemistry. The results suggest that both the carboxyl and the amino groups contribute to the antioxidation activity of CNDs through either a direct or indirect hydrogen atom transfer reaction with DPPH?.
关键词： carbon nanodots,radical scavenging,electro-chemistry,functional groups,antioxidation,charge transfer
更新于2025-11-19 16:56:35
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In suit inducing electron-donating and electron-withdrawing groups in carbon nitride by one-step NH4Cl-assisted route: A strategy for high solar hydrogen production efficiency
摘要： Owing to insu?cient active sites, strongly bound excitons and insu?cient optical absorption, polymer semiconductors have only shown mild activity as potential candidates for photocatalysis. A g-C3N4 with improved optical absorption capacity, charge transfer performance and porosity was successfully prepared by a one-step NH4Cl-assisted route. Interaction of melamine with NH4Cl preparation of Porous g-C3N4(CN-xy) with active functional groups modi?ed pore wall shown to result in highly crystalline species with a maximum π-π layer stacking distance of heptazine units of 0.321 nm, decreases the optical band gap from 2.80 to 2.13 eV and maximum surface area reached 56.485 m2 g?1. The balanced improvement of the multiple defects of g-C3N4 makes the photocatalytic degradation of RhB and the photocatalytic hydrogen production e?ciency 4 and 5 times higher than the pristine g-C3N4, respectively.
关键词： Photocatalytic,g-C3N4,Porous,Trade-o?,Active functional groups
更新于2025-11-19 16:46:39
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Domino Reaction for the Sustainable Functionalization of Few-Layer Graphene
摘要： The mechanism for the functionalization of graphene layers with pyrrole compounds was investigated. Liquid 1,2,5-trimethylpyrrole (TMP) was heated in air in the presence of a high surface area nanosized graphite (HSAG), at temperatures between 80 °C and 180 °C. After the thermal treatments solid and liquid samples, separated by centrifugation, were analysed by means of Raman, Fourier Transform Infrared (FT-IR) spectroscopy, X-Rays Photoelectron Spectroscopy (XPS) and 1H-Nuclear Magnetic Resonance (1H NMR) spectroscopy and High Resolution Transmission Electron Microscopy (HRTEM). FT-IR spectra were interpreted with the support of Density Functional Theory (DFT) quantum chemical modelling. Raman findings suggested that the bulk structure of HSAG remained substantially unaltered, without intercalation products. FT-IR and XPS spectra showed the presence of oxidized TMP derivatives on the solid adducts, in a much larger amount than in the liquid. For thermal treatments at T ≥ 150 °C, IR spectral features revealed not only the presence of oxidized products but also the reaction of intra-annular double bond of TMP with HSAG. XPS spectroscopy showed the increase of the ratio between C(sp2)N bonds involved in the aromatic system and C(sp3)N bonds, resulting from reaction of the pyrrole moiety, observed while increasing the temperature from 130 °C to 180 °C. All these findings, supported by modeling, led to hypothesize a cascade reaction involving a carbocatalyzed oxidation of the pyrrole compound followed by Diels-Alder cycloaddition. Graphene layers play a twofold role: at the early stages of the reaction, they behave as a catalyst for the oxidation of TMP and then they become the substrate for the cycloaddition reaction. Such sustainable functionalization, which does not produce by-products, allows us to use the pyrrole compounds for decorating sp2 carbon allotropes without altering their bulk structure and smooths the path for their wider application.
关键词： infrared spectroscopy,Density Functional Theory,pyrrole compounds,quantum chemical modelling,graphene layers,Functional Groups
更新于2025-09-23 15:23:52
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Lasera??Triggered Writing and Biofunctionalization of Thiola??Ene Networks
摘要： The light responsivity of ortho-nitrobenzyl esters (o-NBE) is exploited to inscribe μ-scale 2.5D patterns in thiol-ene networks by direct laser writing. For this purpose, a multifunctional thiol and a photosensitive alkene with an o-NBE chromophore are cured upon visible light exposure without inducing a premature photocleavage of the o-NBE links. Once the network is formed, a laser beam source with a wavelength of 375 nm is used for selectively inducing the photocleavage reaction of the o-NBE groups. Positive tone patterns are directly inscribed onto the sample surface without the requirement of a subsequent development step (removing soluble species in an appropriate organic solvent). Along with the realization of dry-developable micropatterns, the chemical surface composition of the exposed areas can be conveniently adjusted since different domains with a tailored content of carboxylic groups are obtained simply by modulating the laser energy dose. In a following step, those are activated and exploited as anchor points for attaching an Alexa-546 conjugated Protein A. Thus, the laser writable thiol-ene networks do not only provide a convenient method for the fabrication of positive tone patterns but also open future prospectives for a wide range of biosensing applications.
关键词： thiol-ene polymers,phototriggered functional groups,biofunctionalization,micropatterning,laser writing
更新于2025-09-23 15:19:57
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Conjugated polyelectrolyte with potassium cations enables inverted perovskite solar cells with an efficiency over 20%
摘要： Defect-passivation functional groups have been extensively explored in perovskite solar cells (PSCs) in recent years; however, most of these groups were organic, and the integration of inorganic functional groups with organic matrixes bearing other functions has rarely been reported. Here, to demonstrate the effective of this integration, the coalition of an inorganic group, K+ ion, and an organic conjugated polyelectrolyte (CPE) matrix which serves as a hole transporting material (HTM) is attempted. The resulting CPE material TB(K) presents much stronger ability of defect-passivation and hole extraction, and thus yields a much lifted power conversion efficiency (PCE) of 20.01% and an increased long-term stability when applied in the inverted PSC devices compared with its control polymer TB(Na), where only the inorganic cations are varied from a defect-passivation group to a common one.
关键词： inorganic functional groups,defect-passivation,perovskite solar cells,hole transporting material,conjugated polyelectrolyte
更新于2025-09-19 17:13:59
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Enhancing Charge Transfer and Photoelectric Characteristics for Organic Solar Cells
摘要： The main purpose of this work is to analyze the effect of steric hindrance on the photoelectric performance of three different donor sensitizers (ZHG5, ZHG6, and ZHG7) by molecular theory simulation engineering. Photoelectric physical and photoelectric chemical parameters are investigated by means of frontier molecular orbital, global reactivity descriptors, optical absorption properties, fluorescent lifetime, charge density difference, and influence of external electric field. The results showed that the performance of the quinoxaline sensitizer was deteriorated by gradually increasing the steric hindrance to auxiliary donors. The optical properties of the hybridization of cir-coronene graphene quantum dot (GR) with the three dyes have been revealed, and the results show that graphene quantum dots can indeed improve the optical properties of solar cells. In addition, nine new molecules were designed by inserting six functional groups; it is found that inserting -CN in the acceptor part of the molecular structure is beneficial to the performance of the sensitizer.
关键词： donor sensitizers,steric hindrance,functional groups,graphene quantum dot,photoelectric performance,molecular theory simulation
更新于2025-09-16 10:30:52
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Interfacial Passivation for Perovskite Solar Cells: The Effects of Functional Group in Phenethylammonium Iodide
摘要： Defect passivation is an effective method to improve the performance of perovskite solar cells. In this study, four phenethylammonium iodide featured with different functional groups directly linking to benzene ring are introduced on the surface of perovskite films ((FAPbI3)1-x(MAPbBr3-yCly)x) to investigate their passivation effects. It’s found that the electron density of the benzene ring has significant influence on the interfacial passivation: phenethylammonium iodide with electron-donating groups (methoxyl and methyl) present favorable passivation effects, while the salt with electron-drawing group (nitro) delivers undesirable impacts. The passivation is attributed to the electrostatic interaction between the benzene ring and the undercoordinated Pb2+ ions. The salts treated films are employed to fabricate solar cells, and an efficiency of 22.98% is achieved. In addition, the treated device shows good long-term stability within 1000 h storage in the dark ambient environment.
关键词： interfacial passivation,perovskite solar cells,phenethylammonium iodide,electron density,functional groups
更新于2025-09-12 10:27:22