Exploiting core-shell synergy for nanosynthesis and mechanistic investigation

From individuals to families: design and application of self-similar chiral nanomaterials

Establishing an intimate relationship between similar individuals is the beginning of self-extension. Various self-similar chiral nanomaterials can be designed using an individual-to-family approach, accomplishing self-extension. This self-similarity facilitates chiral communication, transmission, and amplification of synthons. We focus on describing the marriage of discrete cages to develop self-similar extended frameworks. The advantages of utilizing cage-based frameworks for chiral recognition, enantioseparation, chiral catalysis and sensing are highlighted. To further promote self-extension, fractal chiral nanomaterials with self-similar and iterated architectures have attracted tremendous attention. The beauty of a fractal family tree lies in its ability to capture the complexity and interconnectedness of a family's lineage. As a type of fractal material, nanoflowers possess an overarching importance in chiral amplification due to their large surface-to-volume ratio. This review summarizes the design and application of state-of-the-art self-similar chiral nanomaterials including cage-based extended frameworks, fractal nanomaterials, and nanoflowers. We hope this formation process from individuals to families will inherit and broaden this great chirality.

Recent Development on Transition Metal Oxides-Based Core-Shell Structures for Boosted Energy Density Supercapacitors

In recent years, nanomaterials exploration and synthesis have played a crucial role in advancing energy storage research, particularly in supercapacitor development. Researchers have diversified materials, including metal oxides, chalcogenides, and composites, as well as carbon materials, to enhance energy and power density. Balancing energy density with electrochemical stability remains challenging, driving intensified efforts in advancing electrode materials. This review focuses on recent progress in designing and synthesizing core-shell materials tailored for supercapacitors. The core-shell architecture offers advantages such as increased surface area, redox active sites, electrical conductivity, ion diffusion kinetics, specific capacitance, and cyclability. The review explores the impact of core and shell materials, specifically transition metal oxides (TMOs), on supercapacitor electrochemical behavior. Metal oxide choices, such as cobalt oxide as a preferred core and manganese oxide as a shell, are discussed. The review also highlights characterization techniques for assessing structural, morphological, and electrochemical properties of core-shell materials. Overall, it provides a comprehensive overview of ongoing TMOs-based core-shell material research for supercapacitors, showcasing their potential to enhance energy storage for applications ranging from gadgets to electric vehicles. The review outlines existing challenges and future opportunities in evolving TMOs-based core-shell materials for supercapacitor advancements, holding promise for high-efficiency energy storage devices.

Air-Promoted Light-Driven Hydrogen Production from Bioethanol over Core/Shell Cr2O3@GaN Nanoarchitecture

Light-driven hydrogen production from biomass derivatives offers a path towards carbon neutrality. It is often however operated with the limitations of sluggish kinetics and severe coking. Herein, a disruptive air-promoted strategy is explored for efficient and durable light-driven hydrogen production from ethanol over a core/shell Cr2O3@GaN nanoarchitecture. The correlative computational and experimental investigations show ethanol is energetically favorable to be adsorbed on the Cr2O3@GaN interface, followed by dehydrogenation toward acetaldehyde and protons by photoexcited holes. The released protons are then consumed for H2 evolution by photogenerated electrons. Afterward, O2 can be evolved into active oxygen species and promote the deprotonation and C-C cleavage of the key C2 intermediate, thus significantly lowering the reaction energy barrier of hydrogen evolution and removing the carbon residual with inhibited overoxidation. Consequently, hydrogen is produced at a high rate of 76.9 mole H2 per gram Cr2O3@GaN per hour by only feeding ethanol, air, and light, leading to the achievement of a turnover number of 266,943,000 mole H2 per mole Cr2O3 over a long-term operation of 180 hours. Notably, an unprecedented light-to-hydrogen efficiency of 17.6 % is achieved under concentrated light illumination. The simultaneous generation of aldehyde from ethanol dehydrogenation enables the process more economically promising.

A Thiol-Michael Approach Towards Versatile Functionalized Cyclic Titanium-Oxo Clusters

In expanding our research activities of superlattice engineering, designing new giant molecules is the necessary first step. One attempt is to use inorganic transition metal clusters as building blocks. Efficient functionalization of chemically precise transition metal clusters, however, remains a great challenge to material scientists. Herein, we report an efficient thiol-Michael addition approach for the modifications of cyclic titanium-oxo cluster (CTOC). Several advantages, including high efficiency, mild reaction condition, capability of complete addition, high atom economy, as well as high functional group tolerance were demonstrated. This approach can afford high yields of fully functionalized CTOCs, which provides a powerful platform for achieving versatile functionalization of precise transition metal clusters and further applications.

Gold-semiconductor nanohybrids as advanced phototherapeutics

Phototherapeutics is gaining momentum as a mainstream treatment for cancer, with gold-semiconductor nanocomposites showing promise as potent phototherapeutic agents due to their structural tunability, biocompatibility and functional diversity. Such nanohybrids possess plasmonic characteristics in the presence of gold and the catalytic nature of semiconductor units, as well as the unexpected physicochemical properties arising from the contact interface. This perspective provides an overview of the latest research on gold-semiconductor nanocomposites for photodynamic, photothermal and photocatalytic therapy. The relationship between the spatial configuration of these nanohybrids and their practical performance was explored to deliver comprehensive insights and guidance for the design and fabrication of novel composite nanoplatforms to enhance the efficiency of phototherapeutics, promoting the development of nanotechnology-based advanced biomedical applications.

Cu2O/SnO2 Heterostructures: Role of the Synthesis Procedure on PEC CO2 Conversion

Addressing the urgent need to mitigate increasing levels of CO₂ in the atmosphere and combat global warming, the development of earth-abundant catalysts for selective photo-electrochemical CO₂ conversion is a central and pressing challenge. Toward this purpose, two synthetic strategies for obtaining a Cu₂O-SnO₂ catalyst, namely co-precipitation and core-shell methods, were compared. The morphology and band gap energy of the synthesized materials were strongly different. The photoactivity of the core-shell catalyst was improved by 30% compared to the co-precipitation one, while its selectivity was shifted towards C₁ products such as CO and formate. The stability of both catalysts was revealed by an easy and fast EIS analysis, indicating how the effective presence of a SnO₂ shell could prevent the modification of the crystalline phase of the catalyst during PEC tests. Finally, directing the selectivity depending on the synthesis method used to produce the final Cu₂O-SnO₂ catalyst could possibly be implemented in syngas and formate transformation processes, such as hydroformylation or the Fischer-Tropsch process.

Three-dimensional nanofabrication via ultrafast laser patterning and kinetically regulated material assembly

A major challenge in nanotechnology is the fabrication of complex three-dimensional (3D) structures with desired materials. We present a strategy for fabricating arbitrary 3D nanostructures with a library of materials including metals, metal alloys, 2D materials, oxides, diamond, upconversion materials, semiconductors, polymers, biomaterials, molecular crystals, and inks. Specifically, hydrogels patterned by femtosecond light sheets are used as templates that allow for direct assembly of materials to form designed nanostructures. By fine-tuning the exposure strategy and features of the patterned gel, 2D and 3D structures of 20- to 200-nm resolution are realized. We fabricated nanodevices, including encrypted optical storage and microelectrodes, to demonstrate their designed functionality and precision. These results show that our method provides a systematic solution for nanofabrication across different classes of materials and opens up further possibilities for the design of sophisticated nanodevices.

Mesoporous Silica Nanoparticles-Based Nanoplatforms: Basic Construction, Current State, and Emerging Applications in Anticancer Therapeutics

In recent years, researchers are developing novel nanoparticles for diagnostic applications using imaging techniques and for therapeutic purposes through drug delivery techniques. The unique physical and chemical properties of mesoporous silica nanoparticles (MSNs) make it possible to integrate a variety of commonly used therapeutic and imaging agents to construct a multimodal synergistic anticancer drug delivery system. Herein, recent advances in MSNs synthesis for drug delivery and smart response applications are reviewed. First, synthetic strategies for the fabrication of ordered MSNs, hollow MSNs, core-shell structured MSNs, dendritic MSNs, and biodegradable MSNs are outlined. Then, the recent research progress in designing functional MSN materials with various controlled release mechanisms in anticancer therapy is discussed, and new properties are introduced to suggest the latest design requirements as drug delivery materials. The review also highlights significant achievements in bioimaging using MSNs and their multifunctional counterparts as delivery vehicles. Finally, personal views on key directions for future work in this area are presented.

A Core–Shell Au@TiO2 and Multi-Walled Carbon Nanotube-Based Sensor for the Electroanalytical Determination of H2O2 in Human Blood Serum and Saliva

A hydrogen peroxide (H₂O₂) sensor was developed based on core–shell gold@titanium dioxide nanoparticles and multi-walled carbon nanotubes modified glassy carbon electrode (Au@TiO₂/MWCNTs/GCE). Core–shell Au@TiO₂ material was prepared and characterized using a scanning electron microscopy and energy dispersive X-ray analysis (SEM/EDX), transmission electron microscopy (TEM), atomic force microscopy (AFM), Raman spectroscopy, X-ray diffraction (XRD) and Zeta-potential analyzer. The proposed sensor (Au@TiO₂/MWCNTs/GCE) was investigated electrochemically using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The analytical performance of the sensor was evaluated towards H₂O₂ using differential pulse voltammetry (DPV). The proposed sensor exhibited excellent stability and sensitivity with a linear concentration range from 5 to 200 µM (R² = 0.9973) and 200 to 6000 µM (R² = 0.9994), and a limit of detection (LOD) of 1.4 µM achieved under physiological pH conditions. The practicality of the proposed sensor was further tested by measuring H₂O₂ in human serum and saliva samples. The observed response and recovery results demonstrate its potential for real-world H₂O₂ monitoring. Additionally, the proposed sensor and detection strategy can offer potential prospects in electrochemical sensors development, indicative oxidative stress monitoring, clinical diagnostics, general cancer biomarker measurements, paper bleaching, etc.

Low recombination rates and improving charge transfer as decisive conditions for high current densities and fill factors in ZnS complex systems

The growth of ZnS photoelectrodes on ZnO particles identified as ZnO/ZnS(ZC + TAA) by the microwave-assisted hydrothermal method showed excellent photovoltaic parameters of J_SC = 1.2 mA cm^-2 and FF = 0.66, even compared to ZnS(ZC + TAA) used as a reference sample with J_SC = 0.15 mA cm^-2 and FF = 0.52. A careful analysis indicates that the better charge transfer and the higher resistance to recombination present in the ZnO/ZnS(ZC + TAA) samples were the origin of the best photovoltaic behavior. These assertions are supported by a set of samples synthesized from different precursors resulting in different crystal structures, which can be directly associated with current densities and fill factors. All aspects about synthesis and optical/electronic parameters associated with structural features will be available in this article.

Anisotropic dual-plasmonic hetero-nanostructures with tunable plasmonic coupling effects

The influence of plasmonic coupling effects between different components in Au NRs@Cu_2-x Se nanostructures on their characteristics was studied. To this aim, anisotropic Au@Cu_2-x Se hetero-nanostructures with well-controlled design and optical properties were obtained. The LSPR bands of gold and copper selenide are superpositioned in the NIR region, resulting in superior photocatalytic properties of the nanostructures.

Single Molecule-Level Detection via Liposome-Based Signal Amplification Mass Spectrometry Counting Assay

Because of the low atomization and/or ionization efficiencies of many biological macromolecules, the application of mass spectrometry to the direct quantitative detection of low-abundance proteins and nucleic acids remains a significant challenge. Herein, we report mass spectrum tags (MS-tags) based upon gold nanoparticle (AuNP)-templated phosphatidylcholine phospholipid (DSPC) liposomes, which exhibit high and reliable signals via electrospray ionization (ESI). Using these MS-tags, we constructed a liposome signal amplification-based mass spectrometric (LSAMS) "digital" counting assay to enable ultrasensitive detection of target nucleic acids. The LSAMS system consists of liposomes modified with a gold nanoparticle core and surface-anchored photocleavable DNA. In the presence of target nucleic acids, the modified liposome and a magnetic bead simultaneously hybridize with the target nucleic acid. After magnetic separation and photolysis, the MS-tag is released and can be analyzed by ESI-MS. At very low target concentrations, one liposome particle corresponds to one target molecule; thus, the concentration of the target can be estimated by counting the number of liposomes. With this assay, hepatitis C (HCV) virus RNA was successfully analyzed in clinical samples.

Core-Shell Structured Micro-Nanomotors: Construction, Shell Functionalization, Applications, and Perspectives

The successful integration of well-designed micro-nanomotors (MNMs) with diverse functional systems, such as, living systems, remote actuation systems, intelligent sensors, and sensing systems, offers many opportunities to not only endow them with diverse functionalization interfaces but also bring augmented or new properties in a wide variety of applications. Core-shell structured MNM systems have been considered to play an important role in a wide range of applications as they provide a platform to integrate multiple complementary components via decoration, encapsulation, or functionalization into a single functional system, being able to protect the active species from harsh environments, and bring improved propulsion performance, stability, non-toxicity, multi-functionality, and dispersibility, etc., which are not easily available from the isolated components. More importantly, the hetero-interfaces between individual components within a core-shell structure might give rise to boosted or new physiochemical properties. This review will bring together these key aspects of the core-shell structured MNMs, ranging from advanced protocols, enhanced/novel functionalities arising from diverse functional shells, to integrated core-shell structured MNMs for diverse applications. Finally, current challenges and future perspectives for the development of core-shell structured MNMs are discussed in term of synthesis, functions, propulsions, and applications.

Electrocatalytic deep dehalogenation of florfenicol using Fe-doped CoP nanotubes array for blocking resistance gene expression and microbial inhibition during biochemical treatment

Resistance gene expression and microbial inhibition by halogenated antibiotics is a major environmental concern. Although electrocatalytic dehalogenation can detoxify halogenated antibiotics, the effect of dehalogenation treatment on resistance gene expression and microbial inhibition is poorly understood. Herein, a novel electrocatalyst of Fe-doped CoP nanotubes array on nickel foam (Fe-CoP NTs/NiF) is prepared through a simple ultrasonication of Fe-doped CoP nanowires hydrothermally grown on NiF. The transformation from nanowires to nanotubes improves the crystallinity of CoP and fully exposes active sites, producing energetic atomic hydrogen for dehalogenation. Fe-CoP NTs/NiF exhibits a superior dehalogenation performance towards refractory florfenicol (FLO), achieving 100% removal within 20 min (‒1.2 V vs Ag/AgCl, C₀ = 20 mg L^‒1). The dechlorination ratio reaches nearly 100%, and the defluorination ratio achieves 36.8% within 50 min, showing the best electrocatalytic dehalogenation performance reported so far. Microbial community and correlation analysis show that Proteobacteria is the main potential host of FLO resistance gene. Electrocatalytic reductive dehalogenation pretreatment of FLO can reduce microbial inhibition, maintaining microbial richness and diversity in the subsequent biochemical treatment unit. The electrocatalytic reductive dehalogenation treatment can significantly reduce the relative abundance of FLO resistance gene, showing a reliable process for safe treatment of halogenated antibiotic containing wastewater.

Engineering of magnetic nanoparticles as magnetic particle imaging tracers

Magnetic particle imaging (MPI) has recently emerged as a promising non-invasive imaging technique because of its signal linearly propotional to the tracer mass, ability to generate positive contrast, low tissue background, unlimited tissue penetration depth, and lack of ionizing radiation. The sensitivity and resolution of MPI are highly dependent on the properties of magnetic nanoparticles (MNPs), and extensive research efforts have been focused on the design and synthesis of tracers. This review examines parameters that dictate the performance of MNPs, including size, shape, composition, surface property, crystallinity, the surrounding environment, and aggregation state to provide guidance for engineering MPI tracers with better performance. Finally, we discuss applications of MPI imaging and its challenges and perspectives in clinical translation.

Core-shell nanostructures: a simplest two-component system with enhanced properties and multiple applications

With the pace of time, synthesis of nanomaterials has paved paths to blend two or more materials having different properties into hybrid nanoparticles. Therefore, it has become possible to combine two different functionalities in a single nanoparticle and their properties can be enhanced or modified by coupling of two different components. Core-shell technology has now represented a new trend in analytical sciences. Core-shell nanostructures are in demand due to their specific design and geometry. They have internal core of one component (metal or biomolecules) surrounded by a shell of another component. Core-shell nanoparticles have great importance due to their high thermal stability, high solubility and lower toxicity. In this review, recent progress in development of new and sophisticated core-shell nanostructures has been explored. The first section covers introduction throwing light on basics of core-shell nanoparticles. Following section classifies core-shell nanostructures into single core/shell, multicore/single shell, single core/multishell and multicore/multishell nanostructures. Next main section gives a brief description on types of core-shell nanomaterials followed by processes for the synthesis of core-shell nanostructures. Ultimately, the final section focuses on the application areas such as drug delivery, bioimaging, solar cell applications etc.

A General Nanocoating Method via Photoinduced Self-Initiation

Hybrid core-shell nanoparticles play a very significant role in many applications. Here, we report a light-induced oligomer coating on nanoparticles via Norrish type I reaction. The radical species generated via UV irradiation can chemically initiate the photoinitiators, which are then polymerized and deposited on inorganic nanoparticles via heterogeneous nucleation, forming a soft oligomer coating smaller than 40 nm. This coating method is versatile and potentially applicable to many different types of inorganic cores and their assemblies, making it a very useful technique for "freezing" nanoassemblies in solution. Moreover, these oligomer coatings containing radical species can also initiate surface polymerization of both styrenic and acrylic monomers with certain functionalities for different applications such as self-assembly, plasmon tuning, and pH sensing (3.5-4.5).

Application of Core/Shell Nanoparticles in Smart Farming: A Paradigm Shift for Making the Agriculture Sector More Sustainable

Modern agriculture has entered an era of technological plateau where intervention of smarter technology like nanotechnology is imminently required for making this sector economically and environmentally sustainable. Throughout the world, researchers are trying to exploit the novel properties of several nanomaterials to make agricultural practices more efficient. Core/shell nanoparticles (CSNs) have attracted much attention because of their multiple attractive novel features like high catalytic, optical, and electronic properties for which they are being widely used in sensing, imaging, and medical applications. Though it also has the promise to solve a number of issues related to agriculture, its full potential still remains mostly unexplored. This review provides a panoramic view on application of CSNs in solving several problems related to crop production and precision farming practices where the wastage of resources can be minimized. This review also summarizes different classes of CSNs and their synthesis techniques. It emphasizes and analyzes the probable potential applications of CSNs in the field of crop improvement and crop protection, detection of plant diseases and agrochemical residues, and augmentation of chloroplast mediated photosynthesis. In a nutshell, there is enormous scope to formulate and design CSN-based smart tools for applications in agriculture, making this sector more sustainable.

Synthesis of Janus Au@BCP nanoparticles via UV light-initiated RAFT polymerization-induced self-assembly

It is a great challenge to fabricate Janus inorganic/polymeric hybrid nanoparticles with both precisely controlled nanostructures and high yields. Herein, we report a new method to synthesize Janus Au@BCPs via UV light-initiated RAFT polymerization-induced self-assembly in situ at a high solid content. This strategy provides a promising alternative for achieving asymmetric hybrid nanoparticles with a controllable size, tunable morphology and convenient operation.

Novel Strategy for Engineering the Metal-Oxide@MOF Core@Shell Architecture and Its Applications in Cataluminescence Sensing

Cataluminescence is an attractive oxydic luminescence on the gas-solid interface, and metal-oxide@MOF core@shell architectures show great potential for cataluminescence sensing due to their integrated synergistic effect from core and shell components. However, restricting the direct nucleation and growth of metal-organic frameworks (MOFs) on the topologically distinct surface of metal oxides is a great challenge, owing to the high interface energy from the topology mismatch. Herein, for the first time, a novel liquid-phase concentration-controlled nucleation strategy is exploited to induce the direct assembly of a ZIF-8 layer on the surface of CeO₂ nanospheres without any sacrificial templates or further surface modifications. The results show that the construction of the CeO₂@ZIF-8 core@shell architecture can be accomplished within 1 min under the mediation of boosted nucleation kinetics. Furthermore, the universality of this developed strategy is demonstrated by the encapsulation of other metal-oxide cores such as magnetic Fe₃O₄ and ZnCo₂O₄ core particles with a ZIF-8 shell. Notably, compared to the pure CeO₂ and ZIF-8, the obtained CeO₂@ZIF-8 nanocomposite exhibits enhanced analytical performance for the cataluminescence sensing of propanal, in which the shell acts as the major catalytic reaction center, while the core contributes to further improving the catalytic efficiency. The proposed facile synthesis strategy with excellent simplicity, rapidity, and universality brings new insights into the engineering of core@shell advanced functional materials with mismatched topologies for catering to the diverse application demands.

General Formation of Macro-/Mesoporous Nanoshells from Interfacial Assembly of Irregular Mesostructured Nanounits

Mesoporous core-shell nanostructures with controllable ultra-large open channels in their nanoshells are of great interest. However, soft template-directed cooperative assembly to mesoporous nanoshells with highly accessible pores larger than 30 nm, or even above 50 nm into macroporous range, remains a significant challenge. Herein we report a general approach for precisely tailored coating of hierarchically macro-/mesoporous polymer and carbon shells, possessing highly accessible radial channels with extremely wide pore size distribution from ca. 10 nm to ca. 200 nm, on diverse functional materials. This strategy creates opportunities to tailor the interfacial assembly of irregular mesostructured nanounits on core materials and generate various core-shell nanomaterials with controllable pore architectures. The obtained Fe,N-doped macro-/mesoporous carbon nanoshells show enhanced electrochemical performance for the oxygen reduction reaction in alkaline condition.

Dominant Role of Heterojunctions in Gas Sensing with Composite Materials

It is well known that composite materials, consisting of at least two metal oxides, show qualities and sensing behavior very different from the single components. Recently, the preparation of core-shell nanomaterials for gas sensors has become extremely popular. Specifically, these materials have been found to show desirable sensor responses. The preparation of core-shell nanomaterials is, however, complex, limiting the commercial applicability. Composite materials can be more easily attained simply through the mechanical mixing of the various components. Although some studies exist that attempt to compare mechanically mixed composites to those prepared via a synthetic route, these examinations are often flawed, as due to varying preparation methods, the basic characteristics of the materials are not the same. Here, it was possible to separate the role of the contacts between the materials from that of the secondary core-shell structure, by using a soft method to mechanically break apart the structure. This ensures that the difference in morphology is the only change in the material characteristics. It was verified that the composite materials show a different sensing behavior from that of the pure materials. It was also found that regardless of the secondary structure, the composite materials showed very similar sensor responses. By examining materials containing different ratios of Cr₂O₃ to SnO₂, it was possible to attribute the sensor behavior changes to the contacts between the different metal oxides. It was shown that by varying the concentration of each oxide it is possible to attain either an n- or p-type response and at a certain concentration even no response. This work is significant because it identifies that the contact between the materials plays the dominant role in the sensor response and it shows the viability of mechanical mixing for composite sample preparation.

Bioinspired One-Step Synthesis of Pomegranate-like Silica@Gold Nanoparticles with Surface-Enhanced Raman Scattering Activity

Gold-silica (Au-SiO₂) nanohybrids are of great technological importance, and it is crucial to develop facile synthetic protocols to prepare Au-SiO₂ nanohybrids with novel structures. Here we report the bioinspired synthesis of pomegranate-like SiO₂@Au nanoparticles (P-SiO₂@Au NPs) via one-step aqueous synthesis from chloroauric acid and tetraethyl orthosilicate mediated by a basic amino acid, arginine. Effects of chloroauric acid, tetraethyl orthosilicate, and arginine on the morphology and optical property of the products are investigated in detail. The P-SiO₂@Au NPs achieve tunable plasmon resonance depending on the amount of chloroauric acid, which affects the size and shape of the P-SiO₂@Au NPs. Finite-difference time-domain simulations are performed, revealing that the plasmon peak red-shifts with increasing particle size. Arginine serves as the reducing and capping agents for Au as well as the catalyst for SiO₂ formation and also promotes the combination of Au and SiO₂. Formation process of the P-SiO₂@Au NPs is clarified through time-course analysis. The P-SiO₂@Au NPs show good sensitivity for both colloidal and paper-based surface-enhanced Raman scattering measurements. They achieve enhancement factors of 4.3 × 10⁷-8.5 × 10⁷ and a mass detection limit of ca. 1 ng using thiophenol as the model analyte.

An investigation of the photovoltaic parameters of ZnS grown on ZnO(101̄1)

The selective growth of ZnS on ZnO (zinc nitrate versus acetate precursors) affects the photovoltaic parameters when the material is used as a photoanode in solar cells.

Polymer-guided assembly of inorganic nanoparticles

The self-assembly of inorganic nanoparticles is of great importance in realizing their enormous potentials for broad applications due to the advanced collective properties of nanoparticle ensembles. Various molecular ligands (e.g., small molecules, DNAs, proteins, and polymers) have been used to assist the organization of inorganic nanoparticles into functional structures at different hierarchical levels. Among others, polymers are particularly attractive for use in nanoparticle assembly, because of the complex architectures and rich functionalities of assembled structures enabled by polymers. Polymer-guided assembly of nanoparticles has emerged as a powerful route to fabricate functional materials with desired mechanical, optical, electronic or magnetic properties for a broad range of applications such as sensing, nanomedicine, catalysis, energy storage/conversion, data storage, electronics and photonics. In this review article, we summarize recent advances in the polymer-guided self-assembly of inorganic nanoparticles in both bulk thin films and solution, with an emphasis on the role of polymers in the assembly process and functions of resulting nanostructures. Precise control over the location/arrangement, interparticle interaction, and packing of inorganic nanoparticles at various scales are highlighted.

Synthesis and photoluminescence properties of silica-modified SiO2@ANA-Si-Tb@SiO2, SiO2@ANA-Si-Tb-L@SiO2 core-shell-shell nanostructured composites

Three novel core-shell nanostructured composites SiO₂@ANA-Si-Tb, SiO₂@ANA-Si-Tb-L (L = second ligand) with SiO₂ as the core and terbium organic complex as the shell were successfully synthesized. The core and shell were connected together by covalent bonds. The terbium ion was coordinated with organic ligand-forming terbium organic complex in the shell layer. The organosilane (HOOCC₅H₄NN(CONH(CH₂)₃Si(OCH₂CH₃)₃)₂ (abbreviated as ANA-Si) was used as the first ligand and 1,10-phenanthroline (phen) or 2-thenoyltrifluoroacetone (TTA) was used as the second ligand. Furthermore, silica-modified SiO₂@ANA-Si-Tb@SiO₂, SiO₂@ANA-Si-Tb-L@SiO₂ core-shell-shell nanostructured composites were also synthesized by sol-gel chemical route, which involved the hydrolysis and polycondensation processes of tetraethoxysilane (TEOS) using cetyltrimethyl ammonium bromide (CTAB) as a surface-active agent. An amorphous silica shell was coated around the SiO₂@ANA-Si-Tb, SiO₂@ANA-Si-Tb-L core-shell nanostructured composites. The core-shell and core-shell-shell nanostructured composites exhibited excellent luminescence in the solid state. Meanwhile, an improved luminescent stability property of the core-shell-shell nanostructured composites was observed for the aqueous solution. This type of core-shell-shell nanostructured composites exhibited bright luminescence, high stability and good solubility, which may present potential applications in the fields of optoelectronic devices, bio-imaging, medical diagnosis and study on the structure of function composite materials.

Synthesis and Luminescence Properties of Core-Shell-Shell Composites: SiO₂@PMDA-Si-Tb@SiO₂ and SiO₂@PMDA-Si-Tb-phen@SiO₂

Two novel core-shell composites SiO₂@PMDA-Si-Tb, SiO₂@PMDA-Si-Tb-phen with SiO₂ as the core and terbium organic complex as the shell, were successfully synthesized. The terbium ion was coordinated with organic ligand forming terbium organic complex in the shell layer. The bi-functional organosilane ((HOOC)₂C₆H₂(CONH(CH₂)₃Si(OCH₂CH₃)₃)₂ (abbreviated as PMDA-Si) was used as the first ligand and phen as the second ligand. Furthermore, the silica-modified SiO₂@PMDA-Si-Tb@SiO₂ and SiO₂@PMDA-Si-Tb-phen@SiO₂ core-shell-shell composites were also synthesized by sol-gel chemical route. An amorphous silica shell was coated around the SiO₂@PMDA-Si-Tb and SiO₂@PMDA-Si-Tb-phen core-shell composites. The core-shell and core-shell-shell composites both exhibited excellent luminescence in solid state. The luminescence of core-shell-shell composites was stronger than that of core-shell composites. Meanwhile, an improved luminescence stability property for the core-shell-shell composites was found in the aqueous solution. The core-shell-shell composites exhibited bright luminescence, high stability, long lifetime, and good solubility, which may present potential applications in the bio-medical field.

A general approach for encapsulating organic crystals in a polyaniline shell

The hydrophobicity and instability of organic crystals restrict their further applications. Here, we present a general and scalable method to encapsulate different organic crystals in a conductive polyaniline (PANI) shell. The shell significantly improves the stability and dispersity of the nanocrystals, without compromising their luminescence intensity.

Self-Assembly of Polymer-Coated Plasmonic Nanocrystals: From Synthetic Approaches to Practical Applications

Self-assembly of plasmonic nanocrystals (PNCs) and polymers provides access to a variety of functionalized metallic-polymer building blocks and higher-order hybrid plasmonic assemblies, and thus is of considerable fundamental and practical interest. The hybrid assemblies often not only inherit individual characteristics of polymers and PNCs but also exhibit distinct photophysical and catalytic properties compared to that of a single PNC building block. The tailorable plasmonic coupling between PNCs within assemblies enables the precise control over localized surface plasmon resonance, which subsequently affords a series of light-driven or photo-activated applications, such as surface-enhanced Raman scattering detection, photoacoustic imaging, photothermal therapy, and photodynamic therapy. In this review, the synthetic strategies of a library of PNC-polymer hybrid building blocks and corresponding assemblies are summarized along with the mechanisms of polymer-assisted self-assembly of PNCs and the concepts for bridging the intrinsic properties of PNC-polymer assemblies to widespread practical applications.

A simple strategy to achieve shape control of Au-Cu2-xS colloidal heterostructured nanocrystals and their preliminary use in organic photovoltaics

Au-Cu2-xS Janus nanostructures with a shape-controlled semiconductor part are successfully built. The key parameters for controlling the morphology of Cu2-xS in Au-Cu2-xS are demonstrated. Coupled local surface plasmon resonance (LSPR) properties in these Au-Cu2-xS NCs give them potential for application in polymer solar cells (PSCs) as an efficient dopant.

Rich Ground-State Chemical Ordering in Nanoparticles: Exact Solution of a Model for Ag-Au Clusters

We show that nanoparticles can have very rich ground-state chemical order. This is illustrated by determining the chemical ordering of Ag-Au 309-atom Mackay icosahedral nanoparticles. The energy of the nanoparticles is described using a cluster expansion model, and a mixed integer programming approach is used to find the exact ground-state configurations for all stoichiometries. The chemical ordering varies widely between the different stoichiometries and displays a rich zoo of structures with nontrivial ordering.

Reconfigurable Polymer Shells on Shape-Anisotropic Gold Nanoparticle Cores

Reconfigurable hybrid nanoparticles made by decorating flexible polymer shells on rigid inorganic nanoparticle cores can provide a unique means to build stimuli-responsive functional materials. The polymer shell reconfiguration has been expected to depend on the local core shape details, but limited systematic investigations have been undertaken. Here, two literature methods are adapted to coat either thiol-terminated polystyrene (PS) or polystyrene-poly(acrylic acid) (PS-b-PAA) shells onto a series of anisotropic gold nanoparticles of shapes not studied previously, including octahedron, concave cube, and bipyramid. These core shapes are complex, rendering shell contours with nanoscale details (e.g., local surface curvature, shell thickness) that are imaged and analyzed quantitatively using the authors' customized analysis codes. It is found that the hybrid nanoparticles based on the chosen core shapes, when coated with the above two polymer shells, exhibit distinct shell segregations upon a variation in solvent polarity or temperature. It is demonstrated for the PS-b-PAA-coated hybrid nanoparticles, the shell segregation is maintained even after a further decoration of the shell periphery with gold seeds; these seeds can potentially facilitate subsequent deposition of other nanostructures to enrich structural and functional diversity. These synthesis, imaging, and analysis methods for the hybrid nanoparticles of anisotropically shaped cores can potentially aid in their predictive design for materials reconfigurable from the bottom up.

Synthesis of Engineered Zeolitic Materials: From Classical Zeolites to Hierarchical Core-Shell Materials

The term "engineered zeolitic materials" refers to a class of materials with a rationally designed pore system and active-sites distribution. They are primarily made of crystalline microporous zeolites as the main building blocks, which can be accompanied by other secondary components to form composite materials. These materials are of potential importance in many industrial fields like catalysis or selective adsorption. Herein, critical aspects related to the synthesis and modification of such materials are discussed. The first section provides a short introduction on classical zeolite structures and properties, and their conventional synthesis methods. Then, the motivating rationale behind the growing demand for structural alteration of these zeolitic materials is discussed, with an emphasis on the ongoing struggles regarding mass-transfer issues. The state-of-the-art techniques that are currently available for overcoming these hurdles are reviewed. Following this, the focus is set on core-shell composites as one of the promising pathways toward the creation of a new generation of highly versatile and efficient engineered zeolitic substances. The synthesis approaches developed thus far to make zeolitic core-shell materials and their analogues, yolk-shell, and hollow materials, are also examined and summarized. Finally, the last section concisely reviews the performance of novel core-shell, yolk-shell, and hollow zeolitic materials for some important industrial applications.

Sacrificial-template-free synthesis of core-shell C@Bi2S3 heterostructures for efficient supercapacitor and H2 production applications

Core-shell heterostructures have attracted considerable attention owing to their unique properties and broad range of applications in lithium ion batteries, supercapacitors, and catalysis. Conversely, the effective synthesis of Bi₂S₃ nanorod core@ amorphous carbon shell heterostructure remains an important challenge. In this study, C@Bi₂S₃ core-shell heterostructures with enhanced supercapacitor performance were synthesized via sacrificial- template-free one-pot-synthesis method. The highest specific capacities of the C@Bi₂S₃ core shell was 333.43 F g^-1 at a current density of 1 A g^-1. Core-shell-structured C@Bi₂S₃ exhibits 1.86 times higher photocatalytic H₂ production than the pristine Bi₂S₃ under simulated solar light irradiation. This core-shell feature of C@Bi₂S₃ provides efficient charge separation and transfer owing to the formed heterojunction and a short radial transfer path, thus efficiently diminishing the charge recombination; it also facilitates plenty of active sites for the hydrogen evolution reaction owing to its mesoporous nature. These outcomes will open opportunities for developing low-cost and noble-metal-free efficient electrode materials for water splitting and supercapacitor applications.