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Insights into the Synthesis Mechanism of Ag <sub/>29</sub> Nanoclusters
摘要： The current understanding of the synthesis mechanisms of noble metal clusters is limited, in particular for Ag clusters. Here, we present a detailed investigation into the synthesis process of atomically monodisperse Ag29 clusters, prepared via reduction of AgNO3 in the presence of dithiolate ligands. Using optical spectroscopy, mass spectrometry and X-ray spectroscopy, it was determined that the synthesis involves a rapid nucleation and growth to species with up to a few hundred Ag atoms. From these larger species, Ag29 clusters are formed and their concentration increases steadily over time. Oxygen plays an important role in the etching of large particles to Ag29. No other stable Ag cluster species are observed at any point during the synthesis.
关键词： synthesis mechanism,Ag29 nanoclusters,optical spectroscopy,X-ray spectroscopy,mass spectrometry
更新于2025-09-23 15:21:01
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Metal Nanoclusters: Engineering Functional Metal Materials at the Atomic Level (Adv. Mater. 47/2018)
摘要： Customizing functional metal materials at an atom-by-atom basis is one of the most ambitious dreams of materials scientists. In article number 1802751, Jianping Xie and co-workers summarize recent progress in introducing such fine capability of structural modulation into functional metal nanoclusters, based on a protein-like hierarchical structure scheme.
关键词： structural modulation,metal nanoclusters,protein-like hierarchical structure
更新于2025-09-23 15:21:01
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Plasmonic Enhanced Gold Nanoclusters-Based Photoelectrochemical Biosensor for Sensitive Alkaline Phosphatase Activity Analysis
摘要： Low-toxicity gold nanoclusters-decorated Ag@SiO2 (Au NCs-Ag@SiO2) nanocomposites modified plasmonic photoelectrodes were firstly fabricated to improve the photoelectric properties of Au NCs and practical application in biological detection. Through adjusting distance between Au NCs and plasmonic silver nanoparticles (Ag NPs), the photocurrent intensity of Au NCs enhanced by 3.8 times attributed to strong competition between enhancement functions of hot electron transfer, local electric field, light scattering effects and quenching functions of nonradiative energy transfer. Further comparison between experimental results and theoretical simulations were conducted to gain a deeper understanding toward the photoelectric enhancement mechanism. Moreover, Au NCs-Ag@SiO2 nanocomposites was successfully applied to the construction of photoelectrochemical (PEC) biosensors for sensitively detecting alkaline phosphatase activity. This proposed PEC biosensor showed a wide linear range from 0.04 to 400 U·L-1, and a low detection limit of 0.022 U·L-1.
关键词： Alkaline phosphatase,Gold nanoclusters,Photoelectrochemical,Ag@SiO2
更新于2025-09-23 15:19:57
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Probing the Advantageous Photosensitization Effect of Metal Nanoclusters over Plasmonic Metal Nanocrystals in Photoelectrochemical Water Splitting
摘要： Atomically precise metal nanoclusters (NCs)-based photocatalytic systems have garnered enormous attention owing to the fascinating merits including unique physicochemical properties, quantum confinement effect and photosensitization effect, which are distinct from conventional metal nanocrystals (NYs). Nevertheless, systematic comparison between electrons photoexcited from metal NCs and hot electrons from surface plasmonic resonance (SPR) effect of metal NYs in boosting photoelectrochemical water splitting reaction remains blank. Here, we report the strict and comprehensive comparison on the capability of electrons photoexcited from glutathione-capped gold nanoclusters (Aux@GSH) and hot electrons from plasmonic excitation of gold nanoparticles (Au NYs) self-transformed from Aux@GSH to trigger the PEC water splitting reaction under visible light irradiation. The results indicate photoelectrons of Aux NCs trigger more efficient charge transport rate than hot electrons of plasmonic Au NYs in terms of light harvesting and conversion efficiency under the identical conditions. Moreover, charge transfer characteristics in Aux NCs and Au NYs-based PEC systems were established. This work would reinforce our deep understanding on these two pivotal sectors of metal nanomaterials for solar energy conversion.
关键词： photosensitization effect,plasmonic metal nanocrystals,charge transfer,photoelectrochemical water splitting,metal nanoclusters
更新于2025-09-23 15:19:57
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Role of Regeneration of Nanoclusters in Dictating the Power Conversion Efficiency of Metal-Nanocluster-Sensitized Solar Cells
摘要： Metal nanoclusters (NCs) have emerged as feasible alternatives to dyes and quantum dots in light energy conversion applications. Despite the remarkable enhancement in power conversion efficiency (PCE) in recent years and the increase in the number of NCs available as sensitizers, a comprehensive understanding of the various interfacial charge-transfer, transport, and recombination events in NCs is still lacking. This understanding is vital to the establishment of design principles for an efficient photoelectrode that uses NCs. In this work, we carefully design a comparison study of two representative NCs, Au and Ag, based on transient absorption spectroscopy and electrochemical impedance spectroscopy, methods that shed light on the true benefits and limitations of NC sensitizers. Low NC regeneration efficiency is the most critical factor that limits the performance of metal-nanocluster-sensitized solar cells (MCSSCs). The slow regeneration that results from sluggish hole transfer kinetics not only limits photocurrent generation efficiency but also has a profound effect on the stability of MCSSCs. This finding calls for urgent attention to the development of an efficient redox couple that has a great hole extraction ability and no corrosive nature. This work also reveals different interfacial behaviors of Au and Ag NCs in photoelectrodes, suggesting that utilizing the benefits of both types of NCs simultaneously by co-sensitization or using AuAg alloy NCs may be one avenue to further PCE improvement in MCSSCs.
关键词： metal nanoclusters,regeneration,light energy conversion,solar cells,hole transfer
更新于2025-09-23 15:19:57
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Reactive Pulsed Laser Deposition of Clustered-Type MoSx (x ~ 2, 3, and 4) Films and Their Solid Lubricant Properties at Low Temperature
摘要： We studied the tribological properties of amorphous molybdenum sulfide (MoSx) thin-film coatings during sliding friction in an oxidizing environment at a low temperature (?100 °C). To obtain films with different sulfur contents (x ~ 2, 3, and 4), we used reactive pulsed laser deposition, where laser ablation of the Mo target was performed in H2S at various pressures. The lowest coefficient of friction (0.08) was observed during tribo-testing of the MoS3 coating. This coating had good ductility and low wear; the wear of a steel counterbody was minimal. The MoS2 coating had the best wear resistance, due to the tribo-film adhering well to the coating in the wear track. Tribo-modification of the MoS2 coating, however, caused a higher coefficient of friction (0.16) and the most intensive wear of the counterbody. The MoS4 coating had inferior tribological properties. This study explored the mechanisms of possible tribo-chemical changes and structural rearrangements in MoSx coatings upon contact with a counterbody when exposed to oxygen and water. The properties of the tribo-film and the efficiency of its transfer onto the coating and/or the counterbody largely depended on local atomic packing of the nanoclusters that formed the structure of the amorphous MoSx films.
关键词： wear,molybdenum sulfides,solid lubricants,nanoclusters,reactive pulsed laser deposition,low temperature,coefficient of friction
更新于2025-09-23 15:19:57
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Ion Implantation - Research and Application || MeV Electron Irradiation of Ion-Implanted Si-SiO2 Structures
摘要： The effect of (10–25) MeV electron irradiation on Si‐SiO2 structures implanted with different ions (Ar, Si, O, B, and P) has been investigated by different methods, such as deep‐level transient spectroscopy (DLTS), thermo‐stimulated current (TSCM), Rutherford backscattering (RBS), and soft X‐ray emission spectroscopy (SXES). It has been shown that in double‐treated Si‐SiO2 structures, the defect generation by high‐energy electrons depends significantly on the location of preliminary implanted ions relative to the Si‐SiO2 interface as well as on the type (n‐ or p‐Si) of silicon wafer. SiO2 surface roughness changes, induced by ion implantation and high‐energy electron irradiation of Si‐SiO2 structures, are observed by the atomic force microscopy (AFM). Si nanoclusters in SiO2 of ion‐implanted Si‐SiO2 structures generated by MeV electron irradiation is also discussed.
关键词： ion implantation,Si nanoclusters,MeV electron irradiation,Si‐SiO2 structures,radiation defects
更新于2025-09-23 15:19:57
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A Schottky-junction-based platinum nanoclusters@silicon carbide nanosheet as long-term stable hydrogen sensors
摘要： Hydrogen gas sensors which could be applied in harsh environments (high temperature, corrosion atmosphere, etc.) are highly demanded in special fields such as aerospace and chemical industry. Here, we have successfully produced a platinum nanoclusters@silicon carbide nanosheets (Pt NCs@SiC NSs) gas sensor via a simple one-step wet chemical reduction reaction. The Pt NCs@SiC NSs show good response (15.7%) towards 500 ppm hydrogen under 300 °C. Besides, this device possesses a good linear response towards different hydrogen concentration under 500 ppm and keeps a good stability in one month. The gas sensing properties of Pt NCs@SiC NSs are mainly from the Schottky junction-based structure, in which both reception and transduction process play important roles. This work provides a simple way to prepare high-temperature hydrogen sensors without complex equipment, and the large-scale preparation is also available.
关键词： hydrogen sensing,Pt nanoclusters@SiC nanosheets,chemical reduction reaction,high-temperature
更新于2025-09-23 15:19:57
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Growth-Rule-Guided Structural Exploration of Thiolate-Protected Gold Nanoclusters
摘要： Understanding the structure and structure?property relationship of atomic and ligated clusters is one of the central research tasks in the field of cluster research. In chemistry, empirical rules such as the polyhedral skeleton electron pair theory (PSEPT) approach had been outlined to account for skeleton structures of many main-group atomic and ligand-protected transition metal clusters. Nonetheless, because of the diversity of cluster structures and compositions, no uniform structural and electronic rule is available for various cluster compounds. Exploring new cluster structures and their evolution is a hot topic in the field of cluster research for both experiment and theory. In this Account, we introduce our recent progress in the theoretical exploration of structures and evolution patterns of a class of atomically precise thiolate-protected gold nanoclusters using density functional theory computations. Unlike the conventional ligand-protected transition metal compounds, the thiolate-protected gold clusters demonstrate novel metal core/ligand shell interfacial structures in which the Aum(SR)n clusters can be divided into an ordered Au(0) core and a group of oligomeric SR[Au(SR)]x (x = 0, 1, 2, 3, ...) protection motifs. Guided by this “inherent structure rule”, we have devised theoretical methods to rapidly explore cluster structures that do not necessarily require laborious global potential energy surface searches. The structural predictions of Au38(SR)24, Au24(SR)20, and Au44(SR)28 nanoclusters were completely or partially verified by the later X-ray crystallography studies. On the basis of the analysis of cluster structures determined by X-ray crystallography and theoretical prediction, a structural evolution diagram for the face-centered-cubic (fcc)-type Aum(SR)n clusters with m up to 92 has been preliminarily established. The structural evolution diagram indicates some basic structural and electronic evolution patterns of thiolate-protected gold nanoclusters. The fcc Aum(SR)n clusters show a genetic structural evolution pattern in which each step of cluster size increase results in the formation of another Au4 tetrahedron or Au3 triangle unit in the Au core, and every increase of a structural unit in the Au core leads to an increase of two electrons in the whole cluster. The unique one- or two-dimensional cluster size evolution, the isomerism of the Au?S framework, and the formation of a double-helical and cyclic tetrahedron network in the fcc Aum(SR)n clusters all can be addressed from this evolution pattern. The summarized cluster structural evolution diagrams enable us to further explore more stable cluster structures and understand their structure?electronic structure?property relationships.
关键词： face-centered-cubic,thiolate-protected gold nanoclusters,density functional theory,electronic structure,structural evolution
更新于2025-09-23 15:19:57
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Stimuli‐Responsive Luminescent Copper Nanoclusters in Alginate and Their Sensing Ability for Glucose
摘要： Visually observable pH-responsive luminescent materials are developed through integrating the properties of aggregation-induced emission enhancement of Cu nanocluster (NCs) and the Ca2+ triggered gelatin of alginate. Sodium alginate, CaCO3 nanoparticles and Cu NCs are dispersed in aqueous solution, which is in a transparent fluid state, showing a weak photoluminescence (PL). The introduced H+ can react with the CaCO3 nanoparticles to produce free Ca2+, which can cross-link the alginate chains into gel networks. Meanwhile, a dramatically increase on the PL intensity of Cu NCs and a blue shift on the PL peak appeared, assigned to the Ca2+ induced enhancement and gelatin induced enhancement, respectively. Their potential application as a sensor for glucose is also demonstrated based on the principle that glucose oxidase can recognize glucose and produce H+, which further triggers the above mentioned two-stage enhancement. A linear relationship between the PL intensity and concentration of glucose in the range of 0.1 to 2.0 mM is obtained, with a limit of detection calculated as 3.2×10-5 M.
关键词： alginate,stimuli‐responsive materials,aggregation-induced emission,photoluminescence,metal nanoclusters,glucose
更新于2025-09-19 17:15:36