Catalyst-assisted growth of CsPbBr perovskite nanowires.

Halide perovskites (HPs), particularly at the nanoscale, attract attention due to their unique optical properties compared to other semiconductors. They exhibit bright emission, defect tolerance, and a broad tunable band gap. The ability to directly transport charge carriers along the HPs nanowires (NWs) has led to the development of methods for their synthesis.

Supercapattery-Diode: Using Layered Double Hydroxide Nanosheets for Unidirectional Energy Storage.

The supercapacitor-diode (CAPode) is a device that integrates the functionality of an ionic diode with that of a conventional supercapacitor. The unique combination of energy storage and rectification properties in CAPodes is relevant for iontronics, alternate current rectifiers, logic operations, grid stabilization, and even biomedical applications. Here, we propose a novel aqueous-phase supercapattery-diode with excellent energy storage [total specific capacity () = 162 C g, energy density = 34 W h kg at 1.

Unconventional Synthesis of Metal (Ni, Co, Ag) Antimony Alloy Particles.

Bimetallic alloy materials attract interest owing to their properties and stability compared to pure metals, especially alloys with nanoscale dimensions. Metal antimony (MSb) alloys, specifically NiSb, are widely used for charge storage applications due to their high stability. Most synthetic approaches to form these materials require drastic conditions (e.

Real-time monitoring of phase transitions in π-SnS nanoparticles.

While the new cubic phase of tin monosulfide, π-SnS, shows potential for various applications, not much work was focused on the phase transitions, thermal stability, and thermal properties of π-SnS. In this work, we addressed these issues using temperature-resolved X-ray diffraction combined with thermo-gravimetric differential scanning calorimetry and thermo-gravimetric infrared spectroscopy. The cubic π-SnS phase nanoparticles capped with polyvinylpyrrolidone were proven stable for 12 hours at 400 °C, pointing out the possible utilization of this new cubic phase at elevated temperatures.

Dynamics of the nanocrystal structure and composition in growth solutions monitored by lab-scale X-ray diffraction.

characterization of nanoparticle (NP) growth has become the state-of-the-art approach for studying their growth mechanisms; there is broad consensus on the reliability and precision of characterization techniques compared to more traditional ones. Nonetheless, most of the currently available methods require the use of sophisticated setups such as synchrotron-based X-ray sources or an environmental liquid transmission electron microscopy (TEM) cell, which are expensive and not readily accessible. Herein, we suggest a new approach to study NP growth mechanisms: using a commercially available heating chamber for time-resolved X-ray diffraction (TR-XRD) measurements of NP growth in solution.

Formation of Copper Oxide Nanotextures on Porous Calcium Carbonate Templates for Water Treatment.

The necessity of providing clean water sources increases the demand to develop catalytic systems for water treatment. Good pollutants adsorbers are a key ingredient, and CuO is one of the candidate materials for this task. Among the different approaches for CuO synthesis, precipitation out of aqueous solutions is a leading candidate due to the facile synthesis, high yield, sustainability, and the reported shape control by adjustment of the counter anions.

Metal/semiconductor interfaces in nanoscale objects: synthesis, emerging properties and applications of hybrid nanostructures.

Hybrid nanostructures, composed of multi-component crystals of various shapes, sizes and compositions are much sought-after functional materials. Pairing the ability to tune each material separately and controllably combine two (or more) domains with defined spatial orientation results in new properties. In this review, we discuss the various synthetic mechanisms for the formation of hybrid nanostructures of various complexities containing at least one metal/semiconductor interface, with a focus on colloidal chemistry.

Novel easy to fabricate liquid crystal composite with potential for electrically or thermally controlled transparency windows.

Switchable liquid crystal (LC) composites are a unique and attractive class of functional materials due to their extensive use in various applications including smart and privacy windows. Demand for developing smart windows with good switchable performance has steadily increasing in the past decades due to their importance in energy saving. Herein, we present the use of novel and highly active switchable LC composite material-octadecanol-doped LC-prepared via a facile, low-cost, and scalable process, for thermally or electrically controlled transparency windows.

Calcareous Foraminiferal Shells as a Template for the Formation of Hierarchal Structures of Inorganic Nanomaterials.

A microorganism template approach has been explored for the fabrication of various well-defined three-dimensional (3D) structures. However, most of these templates suffer from small size (few μm), difficulty to remove the template, or low surface area, which affect their potential use in different applications or makes industrial scale-up difficult. Conversely, foraminifer's microorganisms are large (up to 200 mm), consist of CaCO (easy to dissolve in mild acid), and have a relatively high surface area (≈5 m g).

Directed Assembly of Au-Tipped 1D Inorganic Nanostructures via Nanolithographic Docking.

Controlled assembly of nanostructures is a key challenge in nanotechnology. In this work, we introduce an approach for the controlled assembly of 1D nanodumbbells-Au-tipped semiconductor nanorods-into arbitrary 2D higher architectures, by their chemical docking to nanopatterned functionalities. We realized the docking functionalities via nanoimprinted metallic nanodots functionalized with an organic monolayer, whose terminal thiol groups chemically bind the nanodumbbell tips.

Bioinspired Hierarchical Porous Structures for Engineering Advanced Functional Inorganic Materials.

Tremendous efforts have been directed at designing functional and well-defined 3D structures in recent decades. Many approaches have been devised and are currently used to create 3D structures, including lithography, 3D printing, assembly, and template-mediated (natural or synthetic) methods. Natural scaffolds offer some unique traits, as compared to their artificial counterparts, presenting highly ordered, porous, identical, abundant, and diverse structures.

Electrophoretic deposition of single-source precursors as a general approach for the formation of hybrid nanorod array heterostructures.

Hypothesis: Subjecting colloids to electric fields often results in (electrophoretic) deposition on conductive substrates. Dispersing a single-source precursor (SSP) of choice in an appropriate solvent, should allow its deposition on different substrates. The SSP-solvent interaction might play a role in the deposition (e.

Ternary hybrid nanostructures of Au-CdS-ZnO grown via a solution-liquid-solid route using Au-ZnO catalysts.

Multi-component nanostructures of Au-CdS-ZnO with a novel morphology were synthesized by a non-conventional strategy where seeded growth is combined with solution-liquid-solid (SLS) growth. Each of these synthetic routes is used for growing a different domain of the final heterostructure, where ZnO rods are grown first on Au nanoparticles via heterogeneous nucleation while CdS is later grown between these two domains via SLS, using the Au tip of the preformed Au-ZnO as a catalyst. The in situ alloying of the Au tip with Cd enabled the metal tip to function as an SLS catalyst at a relatively mild reaction temperature which is lower than the melting point of pure Au.

Organic phase synthesis of noble metal-zinc chalcogenide core-shell nanostructures.

Multi-component nanostructures have been attracting tremendous attention due to their ability to form novel materials with unique chemical, optical and physical properties. Development of hybrid nanostructures that are composed of metal-semiconductor components using a simple approach is of interest. Herein, we report a robust and general organic phase synthesis of metal (Au or Ag)-Zinc chalcogenide (ZnS or ZnSe) core-shell nanostructures.

Coating and enhanced photocurrent of vertically aligned zinc oxide nanowire arrays with metal sulfide materials.

Hybrid nanostructures combining zinc oxide (ZnO) and a metal sulfide (MS) semiconductor are highly important for energy-related applications. Controlled filling and coating of vertically aligned ZnO nanowire arrays with different MS materials was achieved via the thermal decomposition approach of single-source precursors in the gas phase by using a simple atmospheric-pressure chemical vapor deposition system. Using different precursors allowed us to synthesize multicomponent structures such as nanowires coated with alloy shell or multishell structures.

Exciton Quenching Due to Copper Diffusion Limits the Photocatalytic Activity of CdS/Cu2S Nanorod Heterostructures.

The formation of donor/acceptor junctions in hybrid nanomaterials is predicted to enhance photocatalytic activity as compared to single-component semiconductor systems. Specifically, nanomaterials containing a junction of n-type cadmium sulfide (CdS) and p-type copper sulfide (Cu2S) formed via cation exchange have been proposed as potential photocatalysts for reactions such as water splitting. Herein, we study the elemental distribution of Cu within these nanostructures using analytical transmission electron microscopy techniques.

Thermal decomposition approach for the formation of α-Fe2O3 mesoporous photoanodes and an α-Fe2O3/CoO hybrid structure for enhanced water oxidation.

Hematite (α-Fe2O3) is one of most investigated oxides for energy applications and specifically for photocatalysis. Many approaches are used to prepare well-controlled films of hematite with good photocatalytic performance. However, most of these methods suffer from a number of disadvantages, such as the small quantities of the product, and the assembly of the nanostructures is usually a secondary process.

Selective growth of metal particles on ZnO nanopyramids via a one-pot synthesis.

Hybrid nanostructures of metal (Cu, Au, Ag)-ZnO nanopyramids were synthesized. These hybrid nanostructures possess two distinct morphologies where the metal can be selectively attached to either the base or the tip of the ZnO pyramids. This is the first time that such morphologies are reported for Cu-ZnO and Ag-ZnO hybrid nanostructures.

Studying quantum dot blinking through the addition of an engineered inorganic hole trap.

An all-inorganic compound colloidal quantum dot incorporating a highly emissive CdSe core, which is linked by a CdS tunneling barrier to an engineered charge carrier trap composed of PbS, is designed, and its optical properties are studied in detail at the single-particle level. Study of this structure enables a deeper understanding of the link between photoinduced charging and surface trapping of charge carriers and the phenomenon of quantum dot blinking. In the presence of the hole trap, a "gray" emissive state appears, associated with charging of the core.

Harnessing thermal expansion mismatch to form hollow nanoparticles.

Nano popcorn: a new formation mechanism for the synthesis of hollow metal oxide nanoparticles through a melt fracture mechanism. The hollow nanoparticles are formed via brittle fracture following the generation of tensile stresses arising due to liquid-phase thermal expansion of a low melting point core metal. The progress of this physical process can be monitored using in situ transmission electron microscopy for a model system of indium/indium oxide.

Synthesis and characterization of hybrid nanostructures.

There has been significant interest in the development of multicomponent nanocrystals formed by the assembly of two or more different materials with control over size, shape, composition, and spatial orientation. In particular, the selective growth of metals on the tips of semiconductor nanorods and wires can act to couple the electrical and optical properties of semiconductors with the unique properties of various metals. Here, we outline our progress on the solution-phase synthesis of metal-semiconductor heterojunctions formed by the growth of Au, Pt, or other binary catalytic metal systems on metal (Cd, Pb, Cu)-chalcogenide nanostructures.

Probing compositional variation within hybrid nanostructures.

We present a detailed analysis of the structural and magnetic properties of solution-grown PtCo-CdS hybrid structures in comparison to similar free-standing PtCo alloy nanoparticles. X-ray absorption spectroscopy is utilized as a sensitive probe for identifying subtle differences in the structure of the hybrid materials. We found that the growth of bimetallic tips on a CdS nanorod substrate leads to a more complex nanoparticle structure composed of a PtCo alloy core and thin CoO shell.

Enhanced semiconductor nanocrystal conductance via solution grown contacts.

We report a 100000-fold increase in the conductance of individual CdSe nanorods when they are electrically contacted via direct solution phase growth of Au tips on the nanorod ends. Ensemble UV-vis and X-ray photoelectron spectroscopies indicate this enhancement does not result from alloying of the nanorod. Rather, low temperature tunneling and high temperature (250-400 K) thermionic emission across the junction at the Au contact reveal a 75% lower interface barrier to conduction compared to a control sample.

Efficient multiple exciton generation observed in colloidal PbSe quantum dots with temporally and spectrally resolved intraband excitation.

We have spectrally resolved the intraband transient absorption of photogenerated excitons to quantify the exciton population dynamics in colloidal PbSe quantum dots (QDs). These measurements demonstrate that the spectral distribution, as well as the amplitude, of the transient spectrum depends on the number of excitons excited in a QD. To accurately quantify the average number of excitons per QD, the transient spectrum must be spectrally integrated.

Caged quantum dots.

Photoactivatable organic fluorophores and fluorescent proteins have been widely adopted for cellular imaging and have been critical for increasing temporal and spatial resolution, as well as for the development of superresolution microscopy techniques. At the same time, semiconducting nanocrystal quantum dots (QDs) have shown superior brightness and photostability compared to both organic fluorophores and proteins. As part of our efforts to develop nanoparticles with novel optical properties, we have synthesized caged quantum dots, which are nonluminescent under typical microscopic illumination but can be activated with stronger pulses of UV light.