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Facile Construction of Defect-rich Rhenium Disulfide/Graphite Carbon Nitride Heterojunction via Electrostatic Assembly for fast Charge Separation and Photoactivity Enhancement
摘要： Graphite carbon nitride (CN) is one of the most researched visible light photocatalysts, but it still cannot be used practically because of its low photoactivity resulting mainly from rapid photogenerated charge recombination. To accelerate charge separation, CN was herein electrostatically assembled with ReS2, a two-dimensional semiconductor to construct heterojunction for the first time. The electrostatic and coordination interactions between CN and defect-rich ReS2 make them close contact to form heterojunctions. The ReS2/CN heterojunction exhibits higher photocatalytic performance in pollutant degradation owing to faster generation of reactive oxygen species than CN, as well as increased visible and near-infrared light absorption because of strong photoabsorption of defect-rich ReS2. The accelerated reactive oxygen species generation for the heterojunction arises from accelerated charge separation, especially fast transfer of holes from CN to ReS2 in assistance of interfacial electric field and great valance-band edge difference. This work provides a novel CN-based heterojunction for photoactivity improvement and illustrates significance of electrostatic attraction in fabricating heterojunctions.
关键词： electrostatic interaction,photocatalytic,rhenium disulfide,graphite carbon nitride,charge separation
更新于2025-11-21 11:03:13
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Directed Nanoscale Self-assembly of Natural Photosystems on Nitrogen-doped Carbon Nanotubes for Solar Energy Harvesting
摘要： Natural photosystems (PSs) have received much attention as a biological solar energy harvester because of their high quantum efficiency for energy transfer. However, the PSs hybridized with solid electrodes exhibit low light-harvesting efficiencies because of poor interface properties and random orientations of PSs, all of which interfere with efficient charge extraction and transfer. Herein, we report the linker-free, oriented self-assembly of natural PSs with nitrogen-doped carbon nanotubes (NCNTs) via electrostatic interaction. Protonated nitrogen-doped sites on the NCNTs facilitate spontaneous immobilization of the negatively charged stroma side of PSs, which provides a favorable orientation for electron transfer without electrically insulating polymer linkers. The resulting PS/NCNT hybrids exhibit a photocurrent density of 1.25 ± 0.08 μA cm-2, which is much higher than that of PS/CNT hybrids stabilized with polyethylenimine (0.60 ± 0.01 μA cm-2) and sodium dodecyl sulfate (0.14 ± 0.01 μA cm-2), respectively. This work emphasizes the importance of the linker-free assembly of PSs into well-oriented hybrid structures to construct an efficient light-harvesting electrode.
关键词： Light-harvesting,Electrostatic interaction,Photosystems,Nitrogen-doped carbon nanotubes,Self-assembly
更新于2025-11-14 15:29:11
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Highly Efficient Energy Transfer from Water Soluble Zinc Silver Indium Sulphide Quantum Dot to Organic J-Aggregates
摘要： The present work has been carried out with an aim to design and develop an efficient light harvesting inorganic-organic hybrid nanoscale material by employing less toxic, environment friendly inorganic substance and also to understand the mechanism of inter-particle electronic interaction between the inorganic and organic components of the nanomaterial. Specifically, the inorganic-organic hybrid associate has been made by integrating water soluble semiconductor QDs (Zinc-silver-indium-sulfide (ZAIS)) and organic J-aggregates of a cyanine dye (S2165). The fabrication of present nano-hybrid system has been achieved via electrostatically driven self-assembly of organic dyes over ZAIS QDs. The interaction between QD and J-aggregates have been investigated by steady state and time resolved fluorescence measurements. Zeta potential measurements have also been performed to understand the role of electrostatic interaction and thermodynamic feasibility of the association process. The investigations have revealed that energy transfer (ET) process between QD and J-aggregates mediated through dipole-dipole mechanism. Interestingly, data analysis based on F?rster theory has further revealed that the ET from QD to J-aggregates is very high indicating efficient electronic coupling between the inorganic QD and the organic J-aggregates. Zeta potential measurements and thermodynamic calculations have demonstrated that the interaction between QD and organic dye is electrostatically driven and the association of organic dyes over QD is thermodynamically feasible. The outcome of the present study is expected to be helpful in designing efficient nanoscale light harvesting devices. Additionally, fluorescence microscopy and toxicity studies on the QDs have also shown its suitability for biological applications.
关键词： energy transfer,fluorescence microscopy,electrostatic interaction,J-aggregates,inorganic-organic hybrid,toxicity studies,quantum dots
更新于2025-09-23 15:21:01
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Barrier-Free Charge Separation Enabled by Electronic Polarization in High-Efficiency Non-Fullerene Organic Solar Cells
摘要： The separation of charge-transfer (CT) states into free charges at the donor/acceptor (D/A) interfaces plays a central role for organic solar cells (OSCs). Because of strong Coulomb attraction, the separation mechanisms are elusive, particularly for the high-efficiency non-fullerene (NF) OSCs with low exciton-dissociation driving forces. Here, we demonstrate that the Coulomb barriers can be substantially overcome by electronic polarization for OSCs based on a series of A-D-A acceptors (ITIC, IT-4F, and Y6). In contrast to fullerene-based D/A heterojunctions, the polarization energies for both donor holes and acceptor electrons are remarkably increased from the interfaces to pure regions in the NF heterojunctions owing to strong stabilization on electrons but destabilization on holes by electrostatic interactions in the A-D-A acceptors. Especially, upon incorporating fluorine substituents and electron-poor cores to ITIC, the increased polarization energies can completely compensate the Coulomb attraction in the IT-4F and Y6 based Heterojunctions, leading to barrierless charge separation.
关键词： electrostatic interaction,induction effect,charge generation,organic photovoltaics,non-fullerene acceptors
更新于2025-09-23 15:19:57
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Electrostatic Interaction Mediates the Formation of Vesicular Structures from Coassembly of PS- <i>b</i> -PAA with Quantum Dots
摘要： Vesicular structures of block copolymers and inorganic nanoparticles with good stability have potential applications in therapeutic drug release and bioimaging. Herein, a block copolymer of polystyrene-b-poly(acrylic acid) (PS48-b-PAA67) and water-soluble AgInS2/ZnS core/shell quantum dots (QDs) capped with gelatin and thioglycolic acid were coassembled in tetrahydrofuran by adding water. The positively charged QDs bind to negatively charged PAA segments through electrostatic interaction. Numerous vesicular structures, such as uniform bilayer vesicles, ?owerlike large compound vesicles, onionlike lamellar structures consisting of alternating PS and PAA&QD layers, and multilamellar vesicles with spaces between concentric vesicle layers were obtained from the coassembly of PS48-b-PAA67 with QDs. The binding of the positively charged QDs to the PAA block in?uenced both the intra-aggregate PAA corona conformation and the interaggregate interactions. The key parameters a?ecting the formation of these vesicular structures included the QD content, solution pH, and water addition rate. Thus, tunable vesicular structures can be prepared and regulated through this simple but e?ective coassembly method.
关键词： electrostatic interaction,vesicular structures,quantum dots,coassembly,block copolymers
更新于2025-09-11 14:15:04
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Interaction mechanism between TiO <sub/>2</sub> nanostructures and bovine leukemia virus proteins in photoluminescence-based immunosensors
摘要： In this research a mechanism of interaction between a semiconducting TiO2 layer and bovine leukemia virus protein gp51, applied in the design of photoluminescence-based immunosensors, is proposed and discussed. Protein gp51 was adsorbed on the surface of a nanostructured TiO2 thin film, formed on glass substrates (TiO2/glass). A photoluminescence (PL) peak shift from 517 nm to 499 nm was observed after modification of the TiO2/glass by adsorbed gp51 (gp51/TiO2/glass). After incubation of the gp51/TiO2/glass in a solution containing anti-gp51, a new structure (anti-gp51/gp51/TiO2/glass) was formed and the PL peak shifted backwards from 499 nm to 516 nm. The above-mentioned PL shifts are attributed to the variations in the self-trapped exciton energy level, which were induced by the changes of electrostatic interaction between the adsorbed gp51 and the negatively charged TiO2 surface. The strength of the electric field affecting the photoluminescence centers, was determined from variations between the PL-spectra of TiO2/glass, gp51/TiO2/glass and anti-gp51/gp51/TiO2/glass. The principle of how these electric field variations are induced has been predicted. The highlighted origin of the changes in the photoluminescence spectra of TiO2 after its protein modification reveals an understanding of the interaction mechanism between TiO2 and proteins that is the key issue responsible for biosensor performance.
关键词： photoluminescence,protein gp51,electrostatic interaction,immunosensors,TiO2,bovine leukemia virus
更新于2025-09-11 14:15:04
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Precise Nanoparticle – Reactant Interaction Outplays Ligand Poisoning in Visible-Light Photocatalysis
摘要： Metal nanoparticles (NPs) and ligands are two inseparable entities. However, ligands present on the surface of NPs can ‘poison’ a photocatalyst by hindering the NP accessibility to reactants and the movement of charge carriers. Here we present an elegant strategy to accomplish efficient photocatalysis by taking advantage of ligands on the NP surface. Our approach of introducing favorable interactions between NP catalyst and reactant is tested in the model photocatalytic reduction of ferricyanide by gold nanoparticles (AuNP). The favorable interaction arising from the precise tuning of electrostatic potential results in the localization of reactants around the AuNP catalyst. The close proximity between AuNP and ferricyanide improves the NP accessibility and electron transfer rate, thereby suppressing the ligand poisoning effect. Such interaction driven enhancement in photocatalytic performances can be prominent in the emerging area of ‘ligand directed product formation’ in NP catalysis.
关键词： Nanoparticles,Gold Nanoparticles,Ligand Poisoning,Electrostatic Interaction,Photocatalysis
更新于2025-09-09 09:28:46
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Selective recognition of Cr (VI) ion as Cr <sub/>2</sub> O <sub/>7</sub><sup>2?</sup> in aqueous medium using CTAB‐capped anthracene‐based nanosensor: Application to real water sample analysis
摘要： Surfactant‐capped nanoparticles of 9, 10‐diphenyl anthracene prepared by reprecipitation method found highly fluorescent due to aggregation‐induced enhanced emission (AIEE). Cetyltrimethyl ammonium bromide (CTAB) surfactant not only generated positive zeta potential on the surface of nanoparticles to attract anions of interest but also stabilized nanoparticles into brick‐shape morphology. The fluorescence of nanoparticles is quenched by Cr2O7 ion very significantly in comparison with other diverse ions, namely, MnO4, S2O8 showed increase in the fluorescence of nanoparticles, the interference found is negligible in the Cr (VI) analysis. The selectivity and sensitivity of nanoparticles for recognition of Cr2O7 were explored by systematic fluorescence titration. The fluorescence quenching data fits into the usual Stern‐Volmer equation. A calibration curve constructed by plotting quenching of fluorescence (ΔF) against concentration of Cr (VI) exhibiting a linear fit in the equation, ΔF = 3070x, is used for the estimation of chromium concentration (x). The correlation coefficient value R2 = 0.998 obtained from curve is nearly equal to 1 indicates linear fit between quenching data and concentration of Cr (VI). The estimated values of limit of detection (LOD) in the method 0.01392 μg.mL?1 is far below the permissible value of Cr (VI) 0.05 μg.mL?1 in drinking water approved by world health organization (WHO) and United State Environmental Protection Agency (USEPA). The proposed method of Cr (VI) detection is applied for real sample collected from hard chrome deposition industry from nearby region. The amount of Cr (VI) estimated by present method is comparable with AAS determination for the same samples.
关键词： Diphenylanthracene nanoparticles,Cr (VI) ion,CTAB,aggregation induced enhanced emission,electrostatic interaction
更新于2025-09-04 15:30:14