Atomically Precise Colloidal Metal Nanoclusters and Nanoparticles: Fundamentals and Opportunities
TL;DR: This review summarizes the major progress in the field, including the principles that permit atomically precise synthesis, new types of atomic structures, and unique physical and chemical properties ofatomically precise nanoparticles, as well as exciting opportunities for nanochemists to understand very fundamental science of colloidal nanoparticles.
Abstract: Colloidal nanoparticles are being intensely pursued in current nanoscience research. Nanochemists are often frustrated by the well-known fact that no two nanoparticles are the same, which precludes the deep understanding of many fundamental properties of colloidal nanoparticles in which the total structures (core plus surface) must be known. Therefore, controlling nanoparticles with atomic precision and solving their total structures have long been major dreams for nanochemists. Recently, these goals are partially fulfilled in the case of gold nanoparticles, at least in the ultrasmall size regime (1–3 nm in diameter, often called nanoclusters). This review summarizes the major progress in the field, including the principles that permit atomically precise synthesis, new types of atomic structures, and unique physical and chemical properties of atomically precise nanoparticles, as well as exciting opportunities for nanochemists to understand very fundamental science of colloidal nanoparticles (such as the s...
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TL;DR: Luminescence in the visible region, especially by clusters protected with proteins, with a large Stokes shift, has been used for various sensing applications, down to a few tens of molecules/ions, in air and water.
Abstract: Atomically precise pieces of matter of nanometer dimensions composed of noble metals are new categories of materials with many unusual properties. Over 100 molecules of this kind with formulas such as Au25(SR)18, Au38(SR)24, and Au102(SR)44 as well as Ag25(SR)18, Ag29(S2R)12, and Ag44(SR)30 (often with a few counterions to compensate charges) are known now. They can be made reproducibly with robust synthetic protocols, resulting in colored solutions, yielding powders or diffractable crystals. They are distinctly different from nanoparticles in their spectroscopic properties such as optical absorption and emission, showing well-defined features, just like molecules. They show isotopically resolved molecular ion peaks in mass spectra and provide diverse information when examined through multiple instrumental methods. Most important of these properties is luminescence, often in the visible–near-infrared window, useful in biological applications. Luminescence in the visible region, especially by clusters prot...
1,443 citations
TL;DR: The model catalyst role of NCs in catalysis is illustrated from theoretical and experimental perspectives, particularly in electrocatalysis, photocatalysis, photoelectric conversion, and catalysis of organic reactions.
Abstract: Improving the knowledge of the relationship between structure and properties is fundamental in catalysis. Recently, researchers have developed a variety of well-controlled methods to synthesize atomically precise metal nanoclusters (NCs). NCs have shown high catalytic activity and unique selectivity in many catalytic reactions, which are related to their ultrasmall size, abundant unsaturated active sites, and unique electronic structure different from that of traditional nanoparticles (NPs). More importantly, because of their definite structure and monodispersity, they are used as model catalysts to reveal the correlation between catalyst performance and structure at the atomic scale. Therefore, this review aims to summarize the recent progress on NCs in catalysis and provide potential theoretical guidance for the rational design of high-performance catalysts. First a brief summary of the synthetic strategies and characterization methods of NCs is provided. Then the primary focus of this review—the model ...
673 citations
TL;DR: Pt2 dimers can be fabricated with a bottom–up approach on graphene using atomic layer deposition, through proper nucleation sites creation, Pt1 single-atom deposition and attaching a secondary Pt atom selectively on the preliminary one.
Abstract: Supported metal clusters containing only a few atoms are of great interest. Progress has been made in synthesis of metal single-atom catalysts. However, precise synthesis of metal dimers on high-surface area support remains a grand challenge. Here, we show that Pt2 dimers can be fabricated with a bottom–up approach on graphene using atomic layer deposition, through proper nucleation sites creation, Pt1 single-atom deposition and attaching a secondary Pt atom selectively on the preliminary one. Scanning transmission electron microscopy, x-ray absorption spectroscopy, and theoretical calculations suggest that the Pt2 dimers are likely in the oxidized form of Pt2Ox. In hydrolytic dehydrogenation of ammonia borane, Pt2 dimers exhibit a high specific rate of 2800 molH2 molPt
−1 min−1 at room temperature, ~17- and 45-fold higher than graphene supported Pt single atoms and nanoparticles, respectively. These findings open an avenue to bottom–up fabrication of supported atomically precise ultrafine metal clusters for practical applications. Controlled fabrication of few-atoms supported catalysts is a major challenge in the synthesis of nanomaterials. Here, the authors show a bottom-up approach to precisely synthesize platinum dimers supported on graphene, which display higher catalytic activity and stability than single atoms and nanoparticles.
645 citations
TL;DR: Promising applications of metal nanoclusters are reviewed, with particular focus on their potential to impact the fields of chemical sensing, bio-imaging, and bio-labeling, and scope for improvements and future perspectives of these novel nanomaterials are highlighted.
Abstract: Due to their atomically precise structures and intriguing chemical/physical properties, metal nanoclusters are an emerging class of modular nanomaterials. Photo-luminescence (PL) is one of their most fascinating properties, due to the plethora of promising PL-based applications, such as chemical sensing, bio-imaging, cell labeling, phototherapy, drug delivery, and so on. However, the PL of most current nanoclusters is still unsatisfactory-the PL quantum yield (QY) is relatively low (generally lower than 20%), the emission lifetimes are generally in the nanosecond range, and the emitted color is always red (emission wavelengths of above 630 nm). To address these shortcomings, several strategies have been adopted, and are reviewed herein: capped-ligand engineering, metallic kernel alloying, aggregation-induced emission, self-assembly of nanocluster building blocks into cluster-based networks, and adjustments on external environment factors. We further review promising applications of these fluorescent nanoclusters, with particular focus on their potential to impact the fields of chemical sensing, bio-imaging, and bio-labeling. Finally, scope for improvements and future perspectives of these novel nanomaterials are highlighted as well. Our intended audience is the broader scientific community interested in the fluorescence of metal nanoclusters, and our review hopefully opens up new horizons for these scientists to manipulate PL properties of nanoclusters. This review is based on publications available up to December 2018.
537 citations
TL;DR: The most important results published up to the end of 2013 are briefly summarized, while the majority of this Review focuses on findings reported within the last three years.
Abstract: Discovered in 2005, cyclic (alkyl)(amino)carbenes (CAACs) are among the most nucleophilic (σ donating) and also electrophilic (π-accepting) stable carbenes known to date. These properties allow them to activate a variety of small molecules and enthalpically strong bonds, to stabilize highly reactive main-group and transition-metal diamagnetic and paramagnetic species, and to bind strongly to metal centers, which gives rise to very robust catalysts. The most important results published up to the end of 2013 are briefly summarized, while the majority of this Review focuses on findings reported within the last three years.
528 citations
References
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01 Jan 1953
TL;DR: In this paper, the Hartree-Fock Approximation of many-body techniques and the Electron Gas Polarons and Electron-phonon Interaction are discussed.
Abstract: Mathematical Introduction Acoustic Phonons Plasmons, Optical Phonons, and Polarization Waves Magnons Fermion Fields and the Hartree-Fock Approximation Many-body Techniques and the Electron Gas Polarons and the Electron-phonon Interaction Superconductivity Bloch Functions - General Properties Brillouin Zones and Crystal Symmetry Dynamics of Electrons in a Magnetic Field: de Haas-van Alphen Effect and Cyclotron Resonance Magnetoresistance Calculation of Energy Bands and Fermi Surfaces Semiconductor Crystals I: Energy Bands, Cyclotron Resonance, and Impurity States Semiconductor Crystals II: Optical Absorption and Excitons Electrodynamics of Metals Acoustic Attenuation in Metals Theory of Alloys Correlation Functions and Neutron Diffraction by Crystals Recoilless Emission Green's Functions - Application to Solid State Physics Appendix: Perturbation Theory and the Electron Gas Index.
21,954 citations
10,184 citations
TL;DR: In this paper, a preliminary survey with the electron microscope of various preparations of colloidal gold, a study was made of the process of nucleation and growth in gold colloids, and it was shown that nucleating agents may be identified with reducing agents which form a mixed polymer with chlorauric ion before the reduction to the nucleus takes place.
Abstract: After a preliminary survey with the electron microscope of various preparations of colloidal gold, a study was made of the process of nucleation and growth in gold colloids. It was shown that nucleating agents may be identified with reducing agents which form a mixed polymer with chlorauric ion before the reduction to the nucleus takes place. It was also shown that the law of growth is exponential. The average size, the deviation from the average size and the character of the particle size distribution curve are determined by the amount of gold, the nucleation process and the law of growth.
6,593 citations
TL;DR: Using two-phase reduction of AuCl4 by sodium borohydride in the presence of an alkanethiol, solutions of 1-3 nm gold particles bearing a surface coating of thiol have been prepared and characterised; this novel material can be handled as a simple chemical compound as mentioned in this paper.
Abstract: Using two-phase (water–toluene) reduction of AuCl4– by sodium borohydride in the presence of an alkanethiol, solutions of 1–3 nm gold particles bearing a surface coating of thiol have been prepared and characterised; this novel material can be handled as a simple chemical compound.
6,251 citations
TL;DR: A method for assembling colloidal gold nanoparticles rationally and reversibly into macroscopic aggregates by using the specificity of DNA interactions to direct the interactions between particles of different size and composition is described.
Abstract: COLLOIDAL particles of metals and semiconductors have potentially useful optical, optoelectronic and material properties1–4 that derive from their small (nanoscopic) size. These properties might lead to applications including chemical sensors, spectro-scopic enhancers, quantum dot and nanostructure fabrication, and microimaging methods2–4. A great deal of control can now be exercised over the chemical composition, size and polydis-persity1,2 of colloidal particles, and many methods have been developed for assembling them into useful aggregates and materials. Here we describe a method for assembling colloidal gold nanoparticles rationally and reversibly into macroscopic aggregates. The method involves attaching to the surfaces of two batches of 13-nm gold particles non-complementary DNA oligo-nucleotides capped with thiol groups, which bind to gold. When we add to the solution an oligonucleotide duplex with 'sticky ends' that are complementary to the two grafted sequences, the nanoparticles self-assemble into aggregates. This assembly process can be reversed by thermal denaturation. This strategy should now make it possible to tailor the optical, electronic and structural properties of the colloidal aggregates by using the specificity of DNA interactions to direct the interactions between particles of different size and composition.
6,188 citations