scholarly journals Surface lattice engineering for fine-tuned spatial configuration of nanocrystals

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Bo Jiang ◽  
Yifei Yuan ◽  
Wei Wang ◽  
Kun He ◽  
Chao Zou ◽  
...  
Keyword(s):  
Energy Storage ◽  
Spatial Configuration ◽  
Lattice Mismatch ◽  
Deposition Process ◽  
Subsequent Growth ◽  
Seeded Growth ◽  
Precise Control ◽  
Surface Lattice ◽  
Hybrid Nanocrystals ◽  
Further Development

AbstractHybrid nanocrystals combining different properties together are important multifunctional materials that underpin further development in catalysis, energy storage, et al., and they are often constructed using heterogeneous seeded growth. Their spatial configuration (shape, composition, and dimension) is primarily determined by the heterogeneous deposition process which depends on the lattice mismatch between deposited material and seed. Precise control of nanocrystals spatial configuration is crucial to applications, but suffers from the limited tunability of lattice mismatch. Here, we demonstrate that surface lattice engineering can be used to break this bottleneck. Surface lattices of various Au nanocrystal seeds are fine-tuned using this strategy regardless of their shape, size, and crystalline structure, creating adjustable lattice mismatch for subsequent growth of other metals; hence, diverse hybrid nanocrystals with fine-tuned spatial configuration can be synthesized. This study may pave a general approach for rationally designing and constructing target nanocrystals including metal, semiconductor, and oxide.

Enriching the branching of Au@PdAu core–shell nanocrystals using a syringe pump: kinetics control meets lattice mismatch

CrystEngComm ◽  
2021 ◽  
Vol 23 (13) ◽  
pp. 2582-2589
Author(s):  
Gongguo Zhang ◽  
Yanyun Ma ◽  
Xiaowei Fu ◽  
Wenjun Zhao ◽  
Feng Liu ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Surface Diffusion ◽  
Lattice Mismatch ◽  
Core Shell ◽  
Syringe Pump ◽  
Seeded Growth ◽  
Gold Nanocrystals

Gold@palladium–gold nanocrystals with a tunable branched shape are prepared via seeded growth, where the use of a syringe pump allows the manipulation over reaction kinetics as coupled by surface diffusion and strain caused by lattice mismatch.

Effect Of Phosphorus On Ge/Si(001) Island Formation

2002 ◽  
Vol 737 ◽  
Author(s):  
Theodore I. Kamins ◽  
Gilberto Medeiros-Ribeiro ◽  
Douglas A. A. Ohlberg ◽  
R. Stanley Williams
Keyword(s):  
Deposition Rate ◽  
Strain Energy ◽  
Competitive Adsorption ◽  
Lattice Mismatch ◽  
Three Dimensional ◽  
Deposition Process ◽  
Thin Layers ◽  
Island Size ◽  
Partial Pressures ◽  
Intermediate Size

ABSTRACTWhen Ge is deposited epitaxially on Si, the strain energy from the lattice mismatch causes the Ge in layers thicker than about four monolayers to form distinctive, three-dimensional islands. The shape of the islands is determined by the energies of the surface facets, facet edges, and interfaces. When phosphorus is added during the deposition, the surface energies change, modifying the island shapes and sizes, as well as the deposition process. When phosphine is introduced to the germane/hydrogen ambient during Ge deposition, the deposition rate decreases because of competitive adsorption. The steady-state deposition rate is not reached for thin layers. The deposited, doped layers contain three different island shapes, as do undoped layers; however, the island size for each shape is smaller for the doped layers than for the corresponding undoped layers. The intermediate-size islands are the most significant; the intermediate-size doped islands are of the same family as the undoped, multifaceted “dome” structures, but are considerably smaller. The largest doped islands appear to be related to the defective “superdomes” discussed for undoped islands. The distribution between the different island shapes depends on the phosphine partial pressure. At higher partial pressures, the smaller structures are absent. Phosphorus appears to act as a mild surfactant, suppressing small islands.

Buffer Layer Thickness and the Properties of InN Thin Films on AIN- Seeded (00.1) Sapphire And (111) Silicon

1994 ◽  
Vol 339 ◽  
Author(s):  
T. J. Kistenmacher ◽  
S. A. Ecelberger ◽  
W. A. Bryden
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
Layer Thickness ◽  
Electrical Transport ◽  
Lattice Mismatch ◽  
Electrical Mobility ◽  
Seeded Growth ◽  
Electrical Transport Properties ◽  
Buffer Layer Thickness ◽  
Homogeneous Strain

ABSTRACTIntroduction of a buffer layer to facilitate heteroepitaxy in thin films of the Group IIIA nitrides has had a tremendous impact on growth morphology and electrical transport. While AIN- and self-seeded growth of GaN has captured the majority of attention, the use of AIN-buffered substrates for InN thin films has also had considerable success. Herein, the properties of InN thin films grown by reactive magnetron sputtering on AIN-buffered (00.1) sapphire and (111) silicon are presented and, in particular, the evolution of the structural and electrical transport properties as a function of buffer layer sputter time (corresponding to thicknesses from ∼50Å to ∼0.64 μm) described. Pertinent results include: (a) for the InN overlayer, structural coherence and homogeneous strain normal to the (00.1) growth plane are highly dependent on the thickness of the AIN-buffer layer; (b) the homogeneous strain in the AIN-buffer layer is virtually nonexistent from a thickness of 200Å (where a significant X-ray intensity for (00.2)AIN is observed); and (c) the n-type electrical mobility for films on AIN-nucleated (00.1) sapphire is independent of AIN-buffer layer thickness, owing to divergent variations in carrier concentration and film resistivity. These effects are in the main interpreted as arising from a competition between the lattice mismatch of the InN overlayer with the substrate and with the AIN-buffer layer.

Characterization of Mechanical Properties in Multifunctional Structural-Energy Storage Nanocomposites for Lightweight Micro Autonomous Systems

2011 ◽  
Author(s):  
Daniel P. Cole ◽  
Monica Rivera ◽  
Mark Bundy
Keyword(s):  
Energy Storage ◽  
Electrode Materials ◽  
Mechanical Performance ◽  
Autonomous Systems ◽  
Deposition Process ◽  
Mechanical Tests ◽  
Energy Storage Materials ◽  
Structural Components ◽  
Storage Materials

A major concern in the design of micro-robotic systems is an on-board energy supply capable of providing the necessary power requirements, while limiting the volume/mass burden to the vehicle. The conventional solution to this design problem is to maximize the energy density of the on-board power supply. An alternative approach is to replace single-function structural components with multifunctional structural-energy storage materials. The mass and volume savings associated with the material substitution could potentially result in improved endurance and/or increased payload (e.g. video camera, microphone, chemical/biological sensors). In this study, carbon nanotube (CNT) based composites were used to fabricate structural-energy storage materials. Specifically, supercapacitor electrodes were constructed from paper covered with CNT ink and from polymer matrices infused with aligned CNT forests. The composites were subject to bulk mechanical tests in order to characterize their suitability as structural components in micro-autonomous systems. Tensile tests on the paper composites show directional and strain rate dependencies. The CNT-ink deposition process was found to degrade the elastic modulus of the paper by approximately 50%, although the tensile strength of the materials was largely unaffected. Preliminary electrical characterization of the CNT-coated electrode materials indicate that the nanomaterials potentially reach a percolation threshold after multiple depositions, resulting in a conductive surface network. Initial results indicate that improvements in the electrical properties of the CNT paper electrodes are met with reductions in the mechanical performance of the composites.

Micropatterning of Monodisperse Spherical Particles by Electrophoretic Deposition Process Using Interdigitated Microarray Electrode

2006 ◽  
Vol 301 ◽  
pp. 243-246 ◽  
Author(s):  
Jun Ichi Hamagami ◽  
Kazuhiro Hasegawa ◽  
Kiyoshi Kanamura
Keyword(s):  
Electrophoretic Deposition ◽  
Electric Field Distribution ◽  
Colloidal Suspension ◽  
Deposition Process ◽  
Electrode System ◽  
Spherical Particles ◽  
Polystyrene Microspheres ◽  
Precise Control ◽  
System A ◽  
Monodisperse Polystyrene

Micrometer wire consisting of microbeads was successfully fabricated onto a patterned conductive electrode substrate by an electrophoretic deposition (EPD) process with precise control of electric field distribution generated in the colloidal suspension. Monodisperse polystyrene microspheres with 320 nm in diameter and an interdigitated microarray Au electrode having 10 μm in width and 5 μm in spacing were used in this EPD system. A micropattern of polystyrene particles with two dimensional arrays was formed onto the patterned electrode by the EPD process with two electrode system using an electrostatic interaction between the electrodes and the charged particles in the suspension.

Forming Gradient Multilayer (GML) Nano Films for Photovoltaic and Energy Storage Applications

2011 ◽  
Vol 1323 ◽  
Author(s):  
Boris Gilman ◽  
Igor Altman
Keyword(s):  
Energy Storage ◽  
High Efficiency ◽  
Low Cost ◽  
Deposition Process ◽  
Material Composition ◽  
Successful Implementation ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
Entire Thickness ◽  
Fast Development

ABSTRACTFor successful implementation of the nanomaterial-based PV and Energy storage devices there is a need for well-structured nano films consisting of a strictly controlled sequence of nanoparticle layers. Most promising nano-films include a “built-in” gradient of a nanoparticle size and/or material composition across the part or entire thickness of the film. Such Gradient Multilayer (GML) nano films will be able to significantly improve a PV efficiency of the 3rd generation Solar Cells and Energy storage devices. The development of GML-based devices is presently limited by lack of simple, inexpensive, scalable, and production-worthy deposition methods that are capable of forming GML nano-film on PV-suitable substrates such as flexible materials.The proposed concept describes novel principles of an advanced non-conventional deposition of the highly efficient GML nano films.The proposed GML deposition method is based on the phenomena of Flying Particles (FP). According to the FP-methods a pre-selected mix of nanoparticles (NP) of various size and/or material composition is deposited on a flexible (or other) substrate in a pre-defined order of NP size and/or composition thus forming GML nano film. Deposited GML film comprises a sequence of size-tuned and/or composition-tuned NP layers, which has a potential for significant increase of PV efficiency.The deposition process includes the NPs launch and flight through a resistant gas ambient. Due to the Stokes aerodynamic laws the FP times-to-target will be different for NP of a different size and/or density (material composition). Simulation is presented to confirm the separation of FP”s of a different size and/or density during their motion through the low-pressure gas. The calculations have been made for the initial stages of the FP process thus establishing the most efficient parameters of the process. Resultant GML nano films are expected to have superior qualities, particularly for building high efficiency / low cost PV panels. The FP-method allows for a fast development and easy implementation in PV manufacturing.

scholarly journals Effective Formation of Well-Defined Polymeric Microfibers and Nanofibers with Exceptional Uniformity by Simple Mechanical Needle Spinning

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 980 ◽  
Author(s):  
Hoik Lee ◽  
Yuma Inoue ◽  
Myungwoong Kim ◽  
Xuehong Ren ◽  
Ick Kim
Keyword(s):  
Polymer Concentration ◽  
Processing Parameters ◽  
Mechanical Force ◽  
Processing Parameter ◽  
Needle Size ◽  
Precise Control ◽  
Spinning Process ◽  
Facile Fabrication ◽  
Further Development ◽  
Highly Uniform

The fabrication of nanofibers with a mechanical force has attracted increasing attention owing to its facile and easy fabrication. Herein, we demonstrate a novel and facile fabrication technique with the mechanical force, needle spinning, which utilizes a needle tip to draw a polymer solution to form fibrous structures. We studied the effect of the processing parameters to the nanofiber structure, namely, the pulling away speed, pulling away distances, needle size, and polymer concentration, which were systemically controlled. As the needle spinning provides an effective route to adjust those parameters, highly uniform nanofibers can be achieved. There are clear tendencies in the diameter; it was increased as the polymer concentration and needle size were increased, and was decreased as the pulling away distance and pulling away speed were increased. Needle spinning with a precise control of the processing parameter enables us to readily fabricate well-defined nanofibers, with controlled dimensions in diameter and length; plus, single nanofibers also can be easily formed. Those features cannot be realized in common spinning process such as electrospinning. Therefore, this technique will lead to further development of the use of mechanical force for nanofiber fabrication and will expand the range of nanofibers applications.

scholarly journals PbS Quantum Dots Decorating TiO2 Nanocrystals: Synthesis, Topology, and Optical Properties of the Colloidal Hybrid Architecture

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2939
Author(s):  
Carlo Nazareno Dibenedetto ◽  
Teresa Sibillano ◽  
Rosaria Brescia ◽  
Mirko Prato ◽  
Leonardo Triggiani ◽  
...  
Keyword(s):  
Optical Properties ◽  
Lattice Mismatch ◽  
Hybrid Structure ◽  
Systematic Investigation ◽  
Hybrid Nanostructures ◽  
Visible Range ◽  
Hybrid Architecture ◽  
Tio2 Nanocrystals ◽  
Seeded Growth ◽  
Experimental Conditions

Fabrication of heterostructures by merging two or more materials in a single object. The domains at the nanoscale represent a viable strategy to purposely address materials’ properties for applications in several fields such as catalysis, biomedicine, and energy conversion. In this case, solution-phase seeded growth and the hot-injection method are ingeniously combined to fabricate TiO2/PbS heterostructures. The interest in such hybrid nanostructures arises from their absorption properties that make them advantageous candidates as solar cell materials for more efficient solar light harvesting and improved light conversion. Due to the strong lattice mismatch between TiO2 and PbS, the yield of the hybrid structure and the control over its properties are challenging. In this study, a systematic investigation of the heterostructure synthesis as a function of the experimental conditions (such as seeds’ surface chemistry, reaction temperature, and precursor concentration), its topology, structural properties, and optical properties are carried out. The morphological and chemical characterizations confirm the formation of small dots of PbS by decorating the oleylamine surface capped TiO2 nanocrystals under temperature control. Remarkably, structural characterization points out that the formation of heterostructures is accompanied by modification of the crystallinity of the TiO2 domain, which is mainly ascribed to lattice distortion. This result is also confirmed by photoluminescence spectroscopy, which shows intense emission in the visible range. This originated from self-trapped excitons, defects, and trap emissive states.

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