Silicon eccentric shell nanoparticles fabricated by template-assisted deposition for Mie magnetic resonances enhanced light confinement.

We report a structure of silicon eccentric shell particles array, fabricated by the SiOparticles monolayer array assisted deposition of amorphous Si, for high-efficiency light confinement. The SiOparticles monolayer array is tailored to regulate its interparticle distance, followed by silicon film deposition to obtain silicon eccentric shell arrays with positive and negative off-center distance. We studied the Mie resonances of silicon solid sphere, concentric shell, eccentric shell and observed that the eccentric shell with positive off-centersupports superior light confinement because of the enhanced Mie magnetic resonances.

Progressive algorithm for the scattering of electromagnetic waves by a multilayered eccentric sphere.

This paper presents a general progressive algorithm for the computational study of electromagnetic wave scattering by a multilayered eccentric nanoparticle. The presented methodology is based on a combination of the vector addition theorem for spherical wave functions and an efficient progressive algorithm that matches the boundary conditions of every two adjacent shell layers from the outmost to the innermost layer. As a result, only a solution of small-sized matrices is required rather than solving a large set of system equations as reported in other works.

Bubble rising and interaction in ternary fluid flow: a phase field study.

Bubble-droplet interaction is essential in the gas-flotation technique employed in wastewater treatment. However, due to the limitations of experimental methods, the details of the fluid flow involved have not been fully understood. Therefore, a phase field model for a three-phase flow was developed to study the rise of a single bubble and bubble-droplet interactions.

Efficient progressive algorithm for light scattering of a multilayered concentric nanoparticle.

An efficient progressive methodology is presented for the computation of multi-scattering of electromagnetic waves by a multilayered concentric nanoparticle. Instead of solving a large set of system equations as reported in other works, the proposed approach utilizes a progressive algorithm which considers two adjacent shell layers at a time, marching progressively from the innermost to the outmost layer, and requires only multiplication of 4×4 matrices. The progressive algorithm yields the analytical expression for the scattering parameter of the concentric particle.

Targeted Nanoscale 3D Thermal Imaging of Tumor Cell Surface with Functionalized Quantum Dots.

Measuring the changes in tumor cell surface temperature can provide insights into cellular metabolism and pathological features, which is significant for targeted chemotherapy and hyperthermic therapy. However, conventional micro-nano scale methods are invasive and can only measure the temperature of cells across a single plane, which excludes specific organelles. In this study, fluorescence quantum dots (QDs) are functionalized with the membrane transport protein transferrin (Tf) as a thermo-sensor specific for tumor cell membrane.

Interdigital electrodes of air@NiO porous nanoshells for high performance microsupercapacitors by thermally-assisted 3D printing.

Microsupercapacitors of air@NiO porous nanoshells are manufactured by a novel thermally-assisted 3D printing process. It entails the use of printing inks of the moderate solid content of CNT-PS@Ni-precursor-nanoparticle mixture, a real-time heating substrate to print 3D interdigital electrodes, and subsequent thermal annealing to convert PS@Ni-precursor particles into air@NiO porous nanoshells. The microstructure of 3D printed electrodes is characterized by air@NiO porous nanoshells being well dispersed in the CNT network.

Hybrid nanostructure of SiO@Si with Au-nanoparticles for surface enhanced Raman spectroscopy.

In this study, a structure of large-area orderly-arranged SiO@Si core-shell nanoparticles decorated with Au nanoparticles was fabricated for surface-enhanced Raman spectroscopy (SERS). This hybrid structure features light confinement in the Si shells and a uniform distribution of localized electric hot spots. FDTD simulations were carried out to examine the near-field enhancement response of this structure.

Molecular Dynamics Simulation on the Electrowetting Behaviors of the Ionic Liquid [BMIM][BF] on a Solid Substrate.

Compared with traditional aqueous solutions, ionic liquids have important application prospects in the field of wetting and electrowetting due to the advantages of high electric conductivity, long liquid range, and low volatility. In this paper, molecular dynamics method was employed to investigate the wetting and electrowetting behaviors of the nanodroplet of ionic liquid on a solid substrate, as well as the distribution of ionic groups. The ionic liquid is 1-butyl-3-methyl tetra-fluoroborate and coarse grained to simplify the molecular simulation model.

Multilayered Dual Functional SiO@Au@SiO@QD Nanoparticles for Simultaneous Intracellular Heating and Temperature Measurement.

This paper discusses synthesis and application of dual functional SiO@Au@SiO@QD composite nanoparticles for integrated intracellular heating with temperature motoring. The particles are of multilayered concentric structure, consisting of Au nanoshells covered with quantum dots, with the former for infrared heating through localized surface plasma resonance while the later for temperature monitoring. The key to integrate plasmonic-heating/thermal-monitoring on a single composite nanoparticle is to ensure that the quantum dots be separated at a certain distance away from the Au shell surface in order to ensure a detectable quantum yield.

Nanoscale 3D temperature gradient measurement based on fluorescence spectral characteristics of the CdTe quantum dot probe.

The existing quantum dot temperature measurement techniques can only measure the planar temperature in the cell but fails in 3D temperature investigation. We present a novel method of measuring the 3D temperature field on nano scale, combining fluorescence spectral characteristics of the CdTe quantum dot probe with optical spatial positioning. Based on dual-helix point spread function, a 3D temperature optical measurement system with a resolution of 0.

Quantum 3D thermal imaging at the micro-nanoscale.

Real-time and accurate measurement of three-dimensional (3D) temperature field gradient maps of cells and tissues would provide an effective experimental method for analyzing the coupled correlation between metabolism and heat, as well as exploring the thermodynamic properties of nanoparticles under complex environments. In this work, a new principle of quantum 3D thermal imaging is proposed. The photoluminescence principle of quantum dots is expounded and CdTe QDs are prepared by aqueous phase synthesis.

Wetting Behaviors of a Nano-Droplet on a Rough Solid Substrate under Perpendicular Electric Field.

Molecular dynamic simulations were adopted to study the wetting properties of nanoscale droplets on rough silicon solid substrate subject to perpendicular electric fields. The effect of roughness factor and electric field strength on the static and dynamic wetting behaviors of a nano-droplet on a solid surface was investigated at the molecular level. Results show that the static contact angle tends to decrease slightly and show small difference with the increase of roughness factor, while it shows an obvious increase for the ramp-shaped surface because the appearing bottom space reduces the wettability of solid surface.

Parametric Study on Electric Field-Induced Micro-/Nanopatterns in Thin Polymer Films.

Electric field-induced micro-/nanopatterns in thin polymer films, sometimes referred as electrohydrodynamic patterning, is a promising technique to fabricate micro-/nanostructures. Extensive attention has been attracted because of its advantages in microcontact (easy demolding) and low cost. Although considerable work has been done on this technique, including both experimental and theoretical ones, there still appears a requirement for understanding the mechanism of electrohydrodynamic patterning.

Thermal sensing with CdTe/CdS/ZnS quantum dots in human umbilical vein endothelial cells.

An experimental methodology is presented to measure the temperature variation in cells with the usage of CdTe/CdS/ZnS core/shell/shell quantum dots as nanothermometers. The photoluminescence spectral shifts from the endocytosed quantum dots were measured and analyzed to show heat generation in the human umbilical vein endothelial cell following Ca stress. Cytotoxicity evaluation has demonstrated the CdTe/CdS/ZnS QDs are biocompatible to cells.

Nano-fabrication of depth-varying amorphous silicon crescent shell array for light trapping.

We report a new structure of depth controllable amorphous silicon (a-Si) crescent shells array, fabricated by the SiO monolayer array assisted deposition of a-Si by plasma enhanced chemical vapor deposition and nanosphere lithography, for high-efficiency light trapping applications. The depth of the crescent shell cavity was tailored by selective etching of a-Si layer of the SiO/a-Si core/shell nanoparticle array with a varied etching time. The morphological changes of the crescent shells were examined by scanning electron microscopy and atomic force microscopy.

3D Printing of Carbon Nanotubes-Based Microsupercapacitors.

A novel 3D printing procedure is presented for fabricating carbon-nanotubes (CNTs)-based microsupercapacitors. The 3D printer uses a CNTs ink slurry with a moderate solid content and prints a stream of continuous droplets. Appropriate control of a heated base is applied to facilitate the solvent removal and adhesion between printed layers and to improve the structure integrity without structure delamination or distortion upon drying.

Deformation Hysteresis of Electrohydrodynamic Patterning on a Thin Polymer Film.

Electrohydrodynamic patterning is a technique that enables micro/nanostructures via imposing an external voltage on thin polymer films. In this investigation, we studied the electrohydrodynamic patterning theoretically and experimentally, with special interest focused on the equilibrium state. It is found that the equilibrium structure height increases with the voltage.

Step-Controllable Electric-Field-Assisted Nanoimprint Lithography for Uneven Large-Area Substrates.

Large-area nanostructures are widely used in various fields, but fabrication on large-area uneven substrates poses a significant challenge. This study demonstrates a step-controllable electric-field-assisted nanoimprint lithography (e-NIL) method that can achieve conformal contact with uneven substrates for high fidelity nanostructuring. Experiments are used to demonstrate the method where a substrate coated with liquid resist is brought into contact with a flexible template driven by the applied electric field.

Long-wave approximation for hybridization modeling of local surface plasmonic resonance in nanoshells.

A hybridization model for the localized surface plasmon resonance of a nanoshell is developed within the framework of long-wave approximation. Compared with the existing hybridization model derived from the hydrodynamic simulation of free electron gas, this approach is much simpler and gives identical results for a concentric nanoshell. Also, with this approach, the limitations associated with the original hybridization model are succinctly stated.

Fast transient thermal analysis of gold nanoparticles in tissue-like medium.

Gold-nanoparticle-based hyperthermia has attracted considerable attention in the recent ten years in cancer treatment. In hyperthermia-based cancer treatment, in order to produce efficient thermal therapy yet without excessive heat damage to human body, besides the steady-state thermal condition, the transient thermal response is of vital importance. As part of theoretical research associated with nanoparticle-mediated hyperthermia therapy for cancer treatment, the transient heat transfer process of laser interacting with gold nanoparticle in tissue-like medium is investigated.

Energy absorption of gold nanoshells in hyperthermia therapy.

The unique optical characteristics of a gold nanoshell motivate the application of nanoshell-based hyperthermia in drug delivery and cancer treatment. However, most of our understanding on energy absorption and heat transfer is still focused on individual particles, which may not be accurate for nanoshell aggregates in a real application due to the strong optical interaction of nanoshells. This paper investigates the relationship between the optical interaction and the interparticle distance in the visible and near-infrared regions by means of a finite-difference time-domain (FDTD) method.