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Preparation of Monodispersed Nanoparticles of Transparent Conductive Oxides
摘要： Generally, indium-tin-oxides (ITO) thin film is prepared by the sputtering process with ITO target, but only 20 % of ITO yielded from the target is deposited on the substrate. Namely, about 80 % ITO is exhausted by the deposition elsewhere far from the substrate. The recycling process of indium is limited so that ca. 20 % ITO of the starting material is lost without any recovery. Even if the recycling of ITO has been carried out in this process, we should prepare ITO target of 5 times more than apparent use of ITO on film. If we change it to printing process from the sputtering, the reduction in ITO use is expected as ca. 50 %, considering the increase in film thickness by printing. Our target technology also includes ITO nanoink for the project. As a result, monodispersed ITO nanoparticles (NPs) with a cubic shape were fabricated by using quaternary ammonium hydroxide-assisted metal hydroxide organogels. These NPs have perfect uniformity in size with beautiful shape, and perfect single crystalline structure including Sn. As we were attempted to make thin film with ITO nanoink, it was successfully fabricated below 200 nm in thickness and the resistivity was drastically decreased below 1.0 × 10–3 Ω cm after heat treatments. GZO nanoink as substitute of ITO has also been developed.
关键词： indium tin oxide,transparent conductive oxides,uniform nanoparticles,shape control
更新于2025-09-23 15:23:52
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Harnessing polymer grafting to control the shape of plasmonic nanoparticles
摘要： Matrix-free polymer grafted nanoparticles (NPs) are single component polymer nanocomposites (PNCs) for which the often reported severe aggregation of the conventional PNCs can be suppressed. For a given particle core, the size and shape of the polymer grafted nanoparticles can be controlled by the molecular weight of the polymer and its grafting density. However, the degree of homogeneity of one-component PNCs depends on the grafted chain molecular weight and grafting density, as well as on the shape of grafted NPs. Surface plasmon resonance enhanced dynamic light scattering from very dilute solutions, yielding both translational and rotational transport coefficients, complemented by UV–Vis extinction spectra, can detect deviations from spheres. Here, we report that poly(isobutylene)-grafted Ag NPs strongly deviate from the spherical shape and are modeled as prolate spheroids. This NP asphericity, due to inhomogeneous grafting, can impact the structure and properties of plasmonic PNCs in the solid state. Thus, characterizing this behavior is a crucial step prior to the formation of one-component PNCs.
关键词： shape control,polymer grafting,dynamic light scattering,UV–Vis extinction spectra,plasmonic nanoparticles
更新于2025-09-23 15:21:01
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Shape-control of CeF <sub/>3</sub> nanocrystals by doping polyoxometalates: syntheses, characterization and tunable photoluminescence
摘要： A series of CeF3 nanocrystals with uniform morphologies have been synthesized by introducing various polyoxometalates as dopants and shape modifiers. The results indicate that the shape and photoluminescence of the CeF3 nanocrystals could be finely tuned by changing the component and amount of the polyoxometalates.
关键词： doping,CeF3 nanocrystals,photoluminescence,shape-control,polyoxometalates
更新于2025-09-19 17:15:36
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Wulff-Based Approach to Modeling the Plasmonic Response of Single Crystal, Twinned, and Core–Shell Nanoparticles
摘要： The growing interest in plasmonic nanoparticles and their increasingly diverse applications is fuelled by the ability to tune properties via shape control, promoting intense experimental and theoretical research. Such shapes are dominated by geometries that can be described by the kinetic Wulff construction such as octahedra, thin triangular platelets, bipyramids, and decahedra, to name a few. Shape is critical in dictating the optical properties of these nanoparticles, in particular their localized surface plasmon resonance behavior, which can be modeled numerically. One challenge of the various available computational techniques is the representation of the nanoparticle shape. Specifically, in the discrete dipole approximation, a particle is represented by discretizing space via an array of uniformly distributed points-dipoles; this can be difficult to construct for complex shapes including those with multiple crystallographic facets, twins, and core?shell particles. Here, we describe a standalone user-friendly graphical user interface (GUI) that uses both kinetic and thermodynamic Wulff constructions to generate a dipole array for complex shapes, as well as the necessary input files for DDSCAT-based numerical approaches. Examples of the use of this GUI are described through three case studies spanning different shapes, compositions, and shell thicknesses. Key advances offered by this approach, in addition to simplicity, are the ability to create crystallographically correct structures and the addition of a conformal shell on complex shapes.
关键词： localized surface plasmon resonance,Wulff construction,plasmonic nanoparticles,shape control,graphical user interface,DDSCAT,discrete dipole approximation
更新于2025-09-16 10:30:52
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Precursor-Mediated Synthesis of Shape-controlled Colloidal CsPbBr <sub/>3</sub> Perovskite Nanocrystals and their Nanofiber-Directed Self-assembly
摘要： Shape control is often necessary to tune the optical and electronic properties of nanocrystals (NCs) and is mostly achieved through manipulation of surface ligands and processing conditions. Here we present a versatile synthesis of colloidal CsPbBr3 perovskite NCs of various shapes (nanorods, nanocubes and nanoplatelets) from an inexpensive steroidal Cs precursor: cesium cholate (CsCh). Cesium cholate has several advantages over the most commonly used Cs-precursor (cesium oleate or Cs2CO3 or CsOAc) such as low-cost, non-hygroscopicity and better reproducibility in the perovskite synthesis. Due to the solubility of this Cs-precursor in polar solvents such as methanol, a miniscule polar environment is created during the nucleation and growth of the nanocrystals leading to the serendipitous formation of nanorods at 180 ℃, whereas using a biphasic mixture of 1-octadecene and methanol, the morphology changes to nanocubes. By lowering the reaction temperature (90 ℃), nanoplatelets with 8-9 monolayers thicknesses are formed. These colloidal NCs of variety of shapes are strongly luminescent with a green emission having narrow emission linewidths (16-17 nm) and high quantum yields (96% for nanocubes, 94% for nanoplatelets). Furthermore, hybrid materials of nanocubes and organogel of a dimeric bile acid-derived ester gelator are obtained through co-assembly in which nanocubes arrange along nanofibers with stable, sharp and bright green emission. This enables spatial ordering of nanocubes ranging from micron to centimeter scale in thin films, which is crucial for advanced optoelectronic applications. To date, there is no report in literature on the anisotropic organization of perovskite CsPbBr3 nanocubes triggered by supramolecular co-assembly involving organogel nanofibers.
关键词： nanocubes,organogel,Shape control,hybrid materials,nanorods,cesium cholate,nanoplatelets,supramolecular co-assembly,colloidal CsPbBr3 perovskite NCs
更新于2025-09-12 10:27:22
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Surface Capping Agents and Their Roles in Shape‐Controlled Synthesis of Colloidal Metal Nanocrystals
摘要： Controlling the shapes and related properties of colloidal metal nanocrystals are key to the realization of their vast applications. Surface capping agents, including neutral molecules, ionic species, macromolecules, and biomolecules, have been extensively used to control the evolution of seeds into nanocrystals with diverse but well-controlled shapes. Here we offer a comprehensive review of these agents, with a focus on the mechanistic understanding of their roles in guiding the shape evolution of metal nanocrystals. We begin with a brief introduction to the early history of capping agents in electroplating and bulk crystal growth, followed by discussion of how they affect the thermodynamics and kinetics involved in a synthesis of metal nanocrystals. We then present representative examples involving both experimental and computational studies to highlight the various capping agents, including their binding selectivity, molecular-level interaction with a metal surface, and impacts on the growth of metal nanocrystals. We also showcase progress in leveraging capping agents to generate nanocrystals with complex structures and/or enhance their catalytic properties. Finally, we discuss various strategies for the exchange or removal of capping agents, together with perspectives on future directions.
关键词： shape control,structure-property relationship,crystal growth,metal nanocrystal,Capping agent
更新于2025-09-11 14:15:04
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Growth Promotion of Targeted Crystal Face by Nano-Processing via Laser Ablation
摘要： Control of crystal shape is an indispensable step for various applications of crystalline products. However, obtaining the desired crystal shape by conventionally tuning environmental conditions (temperature, additives, etc.) cannot always be reached. Recently, we have developed an innovative approach for spatiotemporal control of crystal growth of proteins and amino acids by locally modifying crystal structure (e.g., formation of screw dislocations) via femtosecond (fs) laser ablation. In this work, to clarify the appropriate laser condition for controlling the shape of single crystals with minimized damage, we first systematically investigated the dependence of pulse duration on laser ablation and crystal growth of L-phenylalanine (L-Phe). By using a laser system with tunable pulse durations from fs to nanosecond (ns), we found fs laser ablation can offer nanometer-sized, sharp etching of which diameter was smaller than the diffraction limit. By utilizing such nano-processing via fs laser ablation for promoting the growth of a targeted crystal face, we successfully demonstrated the preparation of a bulky crystal of L-Phe, which are difficult to be obtained by conventional crystallization methods.
关键词： L-phenylalanine,nano-processing,single crystal growth,crystal shape control,femtosecond laser ablation
更新于2025-09-11 14:15:04
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Mixing time between organometallic precursor and ligand: a key parameter controlling ZnO nanoparticle size and shape and processable hybrid materials
摘要： Since the advent of nanoscience, chemists’ grail is to perfectly and reproducibly elaborate nanoparticles (NPs) of fully defined size, shape, polydispersity, and surface state. It implies a total control of the experimental parameters impacting the synthesis. In the preparation of metal oxide nanoparticles using an organometallic approach, we evidenced that the mixing time between the precursor and the ligand is surprisingly a parameter of tremendous importance. Using NMR spectroscopy, Wide Angle X-ray Scattering and computational DFT studies, the formation of Zn-amido oligomers through an acid-base reaction between the organometallic zinc precursor and the amine ligand is demonstrated. Over time, this polymerization process plays a major role on the control of the size and shape of the ZnO nanoparticles formed through hydrolysis reaction. Hence, nanorods are obtained for short mixing time before hydrolysis while isotropic NPs are obtained for longer ones. Furthermore, it induces the formation of a gel with adjustable rheological properties thus opening new opportunities for the design of processable hybrid materials.
关键词： ZnO,gel formation,organometallic synthesis,nanoparticles,size and shape control
更新于2025-09-10 09:29:36
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Shape-dependent photocatalytic performance of SnFe2O4 nanocrystals synthesized by hydrothermal method
摘要： SnFe2O4 nanocrystals (nanocubes and nanodisks) were synthesized without using any surfactant by hydrothermal method. The morphologies of SnFe2O4 nanocrystals were depended mainly on the concentration of NaOH solution in hydrothermal condition. Transient photoelectron chemical analysis showed that the photoelectric performance of SnFe2O4 nanocubes (1.3 μA/cm2) was better than that of SnFe2O4 nanodisks (0.8 μA/cm2). The photocatalytic activity of SnFe2O4 nanocrystals was measured by degradation of Congo red solution under visible light irradiation. As a result, SnFe2O4 nanocubes showed a superior photocatalytic degradation of Congo red with the degradation rate of 92% in 120 min. The SnFe2O4 nanocubes can be recovered easily be a magnet and reused for 5 times with remained degradation ef?ciency about 85%. A possible photocatalytic mechanism has also been proposed. The SnFe2O4 nanocubes have good potential in water treatment applications.
关键词： FeSnO(OH)5,Photocatalytic,Shape control,SnFe2O4
更新于2025-09-10 09:29:36
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Shape Controllable Synthesis of Silver Particles by Selecting the Crystallization Routes
摘要： Classic crystallization describes a burst nucleation followed by a layer-by-layer atom deposition. The non-classic crystallization refers to particle mediated crystallization process. Different crystallization routes lead to the formation of diverse structured materials. Here we report a rational synthesis of silver particles by selecting the crystallization routes. Silver particles were synthesized by a solution reduction approach. The crystallization routes were regulated by adding amino acids to stabilize silver ions which leads to the decrease of the reduction rate. Without amino acids, silver dendrites were largely formed. With the addition of amino acids, flower-like (low concentration of amino acids) and spherical silver (high concentration of amino acid) particles were synthesized. Three kinds of amino acids were tested and the similar results were obtained. The time-dependent characterization on the evolution of silver particles showed that silver dendrites were formed by the classic atom deposition while the other two morphologies were formed by the combination of classic and non-classic crystallization. The silver particles synthesized were evaluated for ethylene epoxidation and the dendritic particles demonstrated a high selectivity.
关键词： catalytic selectivity,silver particles,reaction kinetics,shape control,crystallization
更新于2025-09-09 09:28:46