Silicon‐Based Self‐Assemblies for High Volumetric Capacity Li‐Ion Batteries via Effective Stress Management

Silicon nanoparticles (Si NPs) have been considered as promising anode materials for next‐generation lithium‐ion batteries, but the practical issues such as mechanical structure instability and low volumetric energy density limit their development. At present, the functional energy‐storing architectures based on Si NPs building blocks have been proposed to solve the adverse effects of nanostructures, but designing ideal functional architectures with excellent electrochemical performance is still a significant challenge. This study shows that the effective stress evolution management is applied for self‐assembled functional architectures via cross‐scale simulation and the simulated stress evolution can be a guide to design a scalable self‐assembled hierarchical Si@TiO₂@C (SA‐SiTC) based on core–shell Si@TiO₂ nanoscale building blocks. It is found that the carbon filler and TiO₂ layer can effectively reduce the risk of cracking during (de)lithiation, ensuring the stability of the mechanical structure of SA‐SiTC. The SA‐SiTC electrode shows long cycling stability (842.6 mAh g^?1 after 1000 cycles at 2 A g^?1), high volumetric capacity (174 mAh cm^?3), high initial Coulombic efficiency (80.9%), and stable solid‐electrolyte interphase (SEI) layer. This work provides insight into the development of the structural stable Si‐based anodes with long cycle life and high volumetric energy density for practical energy applications.     

Monodisperse Hollow Supraparticles via Selective Oxidation

A novel and general strategy to fabricate monodisperse hollow supraparticles (SPs) via selective chemical oxidation is developed. Core‐shell SPs made of semiconductor nanocrystals (NCs) are first obtained by an in situ assembly method. Subsequently, the cores can be selectively removed by preferential oxidation with dilute H₂O₂, resulting in formation of monodisperse hollow SPs. The structural parameters of the products, such as size, shell thickness, and composition, are tailored easily. The hollow structures achieved from CdSe/CdS core‐shell SPs possess high fluorescence quantum yields and a large Stokes shift, the latter is remarkably different from that of conventional organic dyes and quantum dots. In addition to simple hollow structures, rattle‐type nanostructures composed of semiconductor SPs or noble metal‐semiconductor hybrids are also prepared, exemplifying the versatility of the proposed strategy.     

Formation of Gold and Silver Nanoparticle Arrays and Thin Shells on Mesostructured Silica Nanofibers

Mesostructured silica nanofibers synthesized in high yields with cetyltrimethylammonium bromide as the structure‐directing agent in HBr solutions are used as templates for the assembly of Au and Ag nanoparticles and the formation of thin Au shells along the fiber axis. Presynthesized spherical Au and Ag nanoparticles are adsorbed in varying amounts onto the silica nanofibers through bifunctional linking molecules. Nonspherical Au nanoparticles with sharp tips are synthesized on the nanofibers through a seed‐mediated growth approach. The number density of nonspherical Au nanoparticles is controlled by varying the amount of seeded nanofibers relative to the amount of supplied Au precursor. This seed‐mediated growth is further used to form continuous Au shells around the silica nanofibers. Both the Au‐ and Ag‐nanoparticle/silica‐nanofiber hybrid nanostructures and silica/Au core/shell fibers exhibit extinction spectra that are distinct from the spectra of Au and Ag nanoparticles in solution, indicating the presence of new surface plasmon resonance modes in the silica/Au core/shell fibers and surface plasmon coupling between closely spaced metal nanoparticles assembled on silica nanofibers. Spherical Au‐ and Ag‐nanoparticle/silica‐nanofiber hybrid nanostructures are further used as substrates for surface‐enhanced Raman spectroscopy, and the enhancement factors of the Raman signals obtained on the Ag‐nanoparticle/silica‐nanofiber hybrid nanostructures are 2 × 10⁵ for 4‐mercaptobenzoic acid and 4‐mercaptophenol and 7 × 10⁷ for rhodamine B isothiocyanate. These hybrid nanostructures are therefore potentially useful for ultrasensitive chemical and biological sensing by using molecular vibrational signatures.     

Multiresponsive Elastic Colloidal Crystals for Reversible Structural Color Patterns

Multiresponsive elastic poly(methyl methacrylate‐butyl acrylate) (P(MMA‐BA)) copolymer nanoparticles with controlled sizes are fabricated through a one‐step method, which further serve as building blocks for the construction of multiresponsive films via self‐assembly. Taking advantage of the relatively low glass transition temperature and the core–shell structure of the copolymer nanoparticles, they possess the capacity to partially deform and fuse at room temperature under dry status, eventually resulting in the enhancement of the mechanical properties as well as the control of optical properties in the assembled ordered structures. The generated elastic films not only can control the concealment or exhibition of the designed color information, but also can rapidly respond to external stimuli such as the solvent, pH, and tensile force in a reversible fashion. These functional elastic copolymer nanoparticles have potential applications in dynamic color display, optical sensing, and anticounterfeiting.     

Functional Organic Semiconductors Assembled via Natural Aggregating Peptides

Specific peptide sequences designed by inspection of protein–protein interfaces have been identified and used as tectons in hybrid functional materials. Here, an 8‐mer peptide derived from an interface of the peroxiredoxin family of self‐assembling proteins is exploited to encode the assembly of the perylene imide‐based organic semiconductor building blocks. By augmenting the peptide with additional functionality to trigger aggregation and manipulate the directionality of peptide‐semiconductor coupling, a series of hybrid materials based on the natural peptide interface is presented. Using spectroscopic probes, the mode of self‐assembly and the electronic coupling between neighboring perylene units is shown to be strongly affected by the number of peptides attached, and by their backbone directionality. The disubstituted material with peptides extending in the N to C direction away from the perylene core exhibits strong coupling and long‐range order, both attractive properties for electronic device applications. A bio‐organic field‐effect transistor is fabricated using this material, highlighting the possibilities of exploiting natural peptide tectons to encode self‐assembly in other functional materials and devices.     

Assembly of Molecular Building Blocks into Integrated Complex Functional Molecular Systems: Structuring Matter Made to Order

Function‐inspired design of molecular building blocks for their assembly into complex systems has been an objective in engineering nanostructures and materials modulation at nanoscale. This article summarizes recent research and inspiring progress in the design/synthesis of various custom‐made chiral, switchable, and highly responsive molecular building blocks for the construction of diverse covalent/noncovalent assemblies with tailored topologies, properties, and functions. Illustrating the judicious selection of building blocks, orthogonal functionalities, and innate physical/chemical properties that bring diversity and complex functions once reticulated into materials, special focus is given to their assembly into porous crystalline networks such as metal/covalent–organic frameworks (MOFs/COFs), surface‐mounted frameworks (SURMOFs), metal–organic cages/rings (MOCs), cross‐linked polymer gels, porous organic polymers (POPs), and related architectures that find diverse applications in life science and various other functional materials. Smart and stimuli‐responsive or dynamic building blocks, once embedded into materials, can be remotely modulated by external stimuli (light, electrons, chemicals, or mechanical forces) for controlling the structure and properties, thus being applicable for dynamic photochemical and mechanochemical control in constructing new forms of matter made to order. Then, an overview of current challenges, limitations, as well as future research directions and opportunities in this field, are discussed.     

From Hybrid Microgels to Photonic Crystals

We have synthesized semiconductor and metal nanoparticles (NPs) in the constrained geometry of polymer microgels. We used electrostatically driven attraction between the ionic groups of the microgels and the precursor cations in the bulk liquid medium to introduce the cations in the interior of the microgel. In the second step, the cations in the microgel interior reacted with the anion (to obtain semiconductor NPs) or they were treated with a reducing agent (to obtain metal NPs). Good control over the size and the concentration of the NPs in the microgel particles was achieved by changing the composition of the corresponding microgel. The doped microgel spheres were heated at pH 4 above the volume‐transition temperature of the polymer to expel the water from the microsphere interior; then the polymer was encapsulated with a hydrophobic polymeric shell. Hybrid core–shell particles were used as the building blocks of the nanostructured material with properties of a photonic crystal.     

Topological Effects on Globular Protein‐ELP Fusion Block Copolymer Self‐Assembly

Perfectly defined, monodisperse fusion protein block copolymers of a thermoresponsive coil‐like protein, ELP, and a globular protein, mCherry, are demonstrated to act as fully biosynthetic analogues to protein‐polymer conjugates that can self‐assemble into biofunctional nanostructures such as hexagonal and lamellar phases in concentrated solutions. The phase behavior of two mCherry‐ELP fusions, E₁₀‐mCherry‐E₁₀ and E₂₀‐mCherry, is investigated to compare linear and bola fusion self‐assembly both in diluted and concentrated aqueous solution. In dilute solution, the molecular topology impacts the stability of micelles formed above the thermal transition temperature of the ELP block, with the diblock forming micelles and the bola forming unstable aggregates. Despite the chemical similarity of the two protein blocks, the materials order into block copolymer‐like nanostructures across a wide range of concentrations at 30 wt% and above, with the bola fusion having a lower order‐disorder transition concentration than the diblock fusion. The topology of the molecule has a large impact on the type of nanostructure formed, with the two fusions forming phases in the opposite order as a function of temperature and concentration. This new system provides a rich landscape to explore the capabilities of fusion architecture to control supramolecular assemblies for bioactive materials.     

Smart Materials by Nanoscale Magnetic Assembly

Magnetic assembly at the nanoscale level holds great potential for producing smart materials with high functional and structural diversity. Generally, the chemical, physical, and mechanical properties of the resulting materials can be engineered or dynamically tuned by controlling external magnetic fields. This Review analyzes the recent research progress on nanoscale magnetic assembly approaches toward the development of smart materials. The magnetic interactions between nanoparticles (both magnetic and nonmagnetic) and the interactions between nanoparticles and external magnetic fields are fully expatiated based on numerical simulations. In particular, the advancements of nanoscale magnetic assembly in responsive optical nanostructures, shape‐morphing systems, and advanced materials with tunable surface properties are introduced in three subsections. The key roles of magnetic interactions in nanoscale assembly toward customizable physical and chemical properties are highlighted, with focus on how to enable direct manipulation of the positional and orientational orders of the building blocks and orientational control of soft matrices through the incorporation of anisotropic magnetic structures.     

Reactive Aramid Nanostructures as High‐Performance Polymeric Building Blocks for Advanced Composites

Traditionally, the field of advanced nanocomposites has relied on a fairly limited set of building blocks; many with low reactivity and of limited variability. These limitations have been addressed by the creation of functionalized nanometer‐scale aramid structures, in the form of nanofibers and nanosheets. These were obtained by deprotonating macroscale, commercial Kevlar yarns using potassium hydroxide in dimethyl sulfoxide to yield stable dispersions of nanometer‐scale aramid fibers that were then hydrolyzed using phosphoric acid (PA). To illustrate the use of these functionally‐active nanostructures as building blocks for nanocomposites, they were crosslinked by glutaraldehyde (GA), and formed into macroscopic thin films by vacuum‐assisted filtration. It was shown that the mechanical properties of these PA/GA treated films can be tuned by varying the amounts of PA and GA used during synthesis, adjusting the relative amounts of hydrolysis and polymerization. These results are the first demonstration that aramid nanometer‐scale fibers can be used to form versatile nanometer‐sized building blocks that can then be crosslinked to fabricate a wide variety of nanostructured aramid materials with tailorable properties.     

Tuning the Unidirectional Electron Transfer at Interfaces with Multilayered Redox‐active Supramolecular Bionanoassemblies

In this work, we present a new strategy to construct redox‐active molecular platforms to be used as molecular rectifiers with tunable and amplifiable electronic readout. The approach is based on using ligand‐receptor biological interactions to bioconjugate electroactive bio‐inorganic building blocks onto metal electrodes. The stability of the self‐assembled interfacial architecture is provided by multivalent macromolecular ligands that act as scaffolds for building‐up the multilayered structures. The ability of these electroactive supramolecular architectures to generate a unidirectional current flow and tune the corresponding electronic readout was demonstrated by mediating and rectifying the electron transfer between redox donors in solution and the Au electrode. The redox centers incorporated into the assembled architecture in a topologically controlled manner are responsible for tuning the amplification of the rectified electronic readout, thus behaving as a tunable bio‐supramolecular diode. Our experimental results obtained with these redox‐active bio‐supramolecular architectures illustrate the versatility of molecular recognition‐directed assembly in combination with hybrid bio‐inorganic building blocks to construct highly functional interfacial architectures.     

Synthesis of Au–CdS Core–Shell Hetero‐Nanorods with Efficient Exciton–Plasmon Interactions

The synthesis of large lattice mismatch metal‐semiconductor core–shell hetero‐nanostructures remains challenging, and thus the corresponding optical properties are seldom discussed. Here, we report the gold‐nanorod‐seeded growth of Au–CdS core–shell hetero‐nanorods by employing Ag₂S as an interim layer that favors CdS shell formation through a cation‐exchange process, and the subsequent CdS growth, which can form complete core–shell structures with controllable shell thickness. Exciton–plasmon interactions observed in the Au–CdS nanorods induce shell thickness‐tailored and red‐shifted longitudinal surface plasmon resonance and quenched CdS luminescence under ultraviolet light excitation. Furthermore, the Au–CdS nanorods demonstrate an enhanced and plasmon‐governed two‐photon luminescence under near‐infrared pulsed laser excitation. The approach has potential for the preparation of other metal‐semiconductor hetero‐nanomaterials with complete core–shell structures, and these Au–CdS nanorods may open up intriguing new possibilities at the interface of optics and electronics.     

Liquid-Metal-Assisted Programmed Galvanic Engineering of Core–shell Nanohybrids for Microwave Absorption

Core–shell nanostructures have received widespread attention because of their potential usage in various technological and scientific fields. However, they still face significant challenges in terms of fabrication of core–shell nanostructure libraries on a controlled, and even programmed scale. This study proposes a general approach to systematically fabricate core–shell nanohybrids using liquid-metal Ga alloys as reconfigurable templates, and the initiation of a local galvanic replacement reaction is demonstrated utilizing an ultrasonic system. Under ultrasonic agitation, the hydrated gallium oxides generated on the liquid metal droplets, simultaneously delaminated themselves from the interfaces. Subsequently, single-metal or bimetallic components are deposited on fresh smooth Ga-based alloys via galvanic reactions to form unique core–shell metal/metal nanohybrids. Controlled and quantitative regulation of the diversity of the non-homogeneous nanoparticle shell layer composition is achieved. The obtained core–shell nanostructures are used as efficient microwave absorbers to dissipate unwanted electromagnetic wave pollution. The effective absorption bands (90% absorption) of core–shell Ga Ni and Ga CoNi nanohybrids are 3.92 and 3.8 GHz at a thickness of 1.4 mm, respectively. This general and advanced strategy enables the growth of other oxides or sulfides by spontaneous interfacial redox reactions for the fabrication of functional materials in the future.     

Thermodynamic Aspects of Molluscan Shell Ultrastructural Morphogenesis

Over the years, molluscan shells have become an exemplar model system to study the process of mineral formation by living organisms, the process of biomineralization. Typically, the shells consist of a number of mineralized ultrastructural motifs, each exhibiting a specific mineral‐organic composite architecture. These are made of calcium carbonate building blocks having a well‐defined three‐dimensional morphology that is significantly different from the shape of inorganically formed counterparts. Shell ultrastructures are known to form via a biologically controlled extracellular mineralization pathway in which the organism has no direct control over mineral formation. The cellular tissue, responsible for shell biomineralization, forms an organic framework and sets‐up the physical conditions necessary for the deposition of a specific morphology, whereas the growth of the mineral part of the shell proceeds spontaneously via the process of self‐assembly. In this feature article, the ability to employ thermodynamic models from classical materials science to describe the process of self‐assembly and structural evolution of a variety of shell architectures is reviewed. Having the potential to offer an analytical framework to express ultrastructure formation in time and in space, these models not only provide a deeper insight into shell biomineralization, but also suggest tools for novel composite materials design.     

Facile Nondestructive Assembly of Tyrosine‐Rich Peptide Nanofibers as a Biological Glue for Multicomponent‐Based Nanoelectrode Applications

Achieving the nondestructive assembly of carbon nanoelectrodes with multiple components in a scalable manner enables effective electrical interfaces among nanomaterials. Here, a facile nondestructive multiscale assembly of multicomponent nanomaterials using self‐assembled tyrosine‐rich peptide nanofibers (TPFs) as a biological glue is reported. The versatile functionalities of the rationally devised tyrosine‐rich short peptide allow for (1) self‐assembly of the peptide into nanofibers using noncovalent interactions, followed by (2) immobilization of spatially distributed metal nanoparticles on the nanofiber surface, and (3) subsequent assembly with graphitic nanomaterials into a percolated network‐structure. This percolated network‐structure of silver nanoparticle (AgNP)‐decorated peptide nanofibers with imbedded single‐walled carbon nanotubes (SWNTs) proves to be a versatile nanoelectrode platform with excellent processability. The SWNT–TPF–AgNP assembly, when utilized as a flexible and transparent multicomponent electronic film, was quite effective for enhancing direct electron transfer (DET) as verified for a third‐generation glucose sensor composed of this film. The simple solution process used to produce the functional nanomaterials could provide a new platform for scalable manufacturing of novel nanoelectrode materials forming effective electrical contacts with molecules from diverse biological systems.     

Biomimetic Chitin–Silk Hybrids: An Optically Transparent Structural Platform for Wearable Devices and Advanced Electronics

The cuticles of insects and marine crustaceans are fascinating models for man‐made advanced functional composites. The excellent mechanical properties of these biological structures rest on the exquisite self‐assembly of natural ingredients, such as biominerals, polysaccharides, and proteins. Among them, the two commonly found building blocks in the model biocomposites are chitin nanofibers and silk‐like proteins with β‐sheet structure. Despite being wholly organic, the chitinous protein complex plays a key role for the biocomposites by contributing to the overall mechanical robustness and structural integrity. Moreover, the chitinous protein complex alone without biominerals is optically transparent (e.g., dragonfly wings), thereby making it a brilliant model material system for engineering applications where optical transparency is essentially required. Here, inspired by the chitinous protein complex of arthropods cuticles, an optically transparent biomimetic composite that hybridizes chitin nanofibers and silk fibroin (β‐sheet) is introduced, and its potential as a biocompatible structural platform for emerging wearable devices (e.g., smart contact lenses) and advanced displays (e.g., transparent plastic cover window) is demonstrated.     

3D2 Self‐Assembling Janus Peptide Dendrimers with Tailorable Supermultivalency

The self‐assembly of peptides enables the construction of self‐assembled peptide nanostructures (SPNs) with chemical composition similar to those of natural proteins; however, the structural complexity and functional properties of SPNs are far beneath those of natural proteins. One of the most fundamental challenges in fabricating more elaborate SPNs lies in developing building blocks that are simultaneously more complex and relatively easy to synthesize. Here, the development of self‐assembling Janus peptide dendrimers (JPDs) is reported, which have fully 3D structures similar to those of globular proteins. For the reliable and convenient synthesis of JPDs, a solid‐phase bifurcation synthesis method is devised. The self‐assembly behavior of JPDs is unique because only the dendrimer generation and not the weight fraction dictates the morphology of SPNs. The coassembly of two JPD building blocks provides an opportunity not only to enlarge the morphological repertoire in a predictable manner but also to discover SPNs with unusual and interesting morphologies. Because JPD assemblies have dual multivalency, i.e., supramolecular and unimolecular multivalency, the JPD system enables the statistical selection of materials with high avidity for the desired cell types and possibly any target receptors.     

Inorganic Solids of CdSe Nanocrystals Exhibiting High Emission Quantum Yield

A general strategy for the assembly of all‐inorganic light‐emitting nanocrystal films with emission quantum yield in the 30–52% range is reported. The present methodology relies on solution‐processing of CdSe nanocrystals into a crystalline matrix of a wide band gap semiconductor (CdS, ZnS), which replaces the original molecular ligands on nanocrystal surfaces with an inorganic medium. Such matrices efficiently protect nanoparticles from the surrounding environment and preserve the quantum confinement of electrical charges in embedded CdSe NCs. In addition to strong emission, fabricated films show excellent thermal and chemical stability, and a large refractive index, which avails their integration into emerging solid‐state nanocrystal devices, including light‐emitting diodes, solar concentrators, and quantum dot lasers.     

Chiral 2D Colloidal Semiconductor Quantum Wells

Induced chirality in colloidal semiconductor nanoparticles has raised significant attention in the past few years as an extremely sensitive spectroscopic tool and due to the promising applications of chiral quantum dots in sensing, quantum optics, and spintronics. Yet, the origin of the induced chiroptical effects in semiconductor nanoparticles is still not fully understood, partly because almost all the theoretical and experimental studies to date are based on the simple model system of a spherical nanocrystal. Here, the realization of induced chirality in atomically flat 2D colloidal quantum wells is shown. A strong circular dichroism (CD) response as well as an absorptive‐like CD line shape is observed in chiral CdSe nanoplatelets (NPLs), significantly differing from that previously observed in spherical dots. Furthermore, this intense CD signal almost completely disappears after coating with a very thin CdS shell. In contrast, CdSe‐CdS core‐crown NPLs exhibit a spectral response which seems to originate independently from the core and the crown regions of the NPL. This work on the one hand further advances the understanding of the fundamental origin of induced chiroptical effects in semiconductor nanoparticles, and on the other opens a pathway toward applications using chiroptical materials.     

Metal–Organic Frameworks Derived from Zero‐Valent Metal Substrates: Mechanisms of Formation and Modulation of Properties

The replicative construction of metal–organic frameworks (MOFs) templated with solvent‐insoluble solid substrates is of marked importance, as it allows for the assembly of 2D and 3D macro‐ and mesoscopic architectures with properties that are challenging to attain by the conventional solution‐based synthesis approach. This work reports an in situ and direct construction of MOFs from zero‐valent metal substrates via a green hydrothermal oxidation–MOF construction chemistry without the use of any additional metal source, chemical reagents, or acidification of solvent, and elucidates the zero‐valent metal derived formation mechanisms of MOFs and their structure modulation to 1D nanofibers (NFs), 2D film, and 3D core–shell microstructures. Through modulation of the competing surface oxidation‐dissolution and MOF crystallization kinetics, Al@MIL‐53 core–shell microstructures and MIL‐53 (Al) NFs are obtained that exhibit unique morphologies and marked properties superior to the conventional MIL‐53 (Al) powders. The generality of zero‐valent metal‐templated synthesis of MOFs is demonstrated with formation of MIL‐53 (Al), HKUST‐1, and ZIF‐7 polycrystalline films on Al, Cu, and Zn metal meshes, elucidating the significance of the approach utilizing solid metal substrate that can be easily processed into various shapes, architectures, and compositions.