Shuoran Chen

Colloidal photonic crystals with narrow stopbands assembled from low-adhesive superhydrophobic substrates.

This article presents a facile approach to centimeter-scale colloidal photonic crystals (PCs) with narrow stopbands assembled on low-adhesive superhydrophobic substrates. The full-width-at-half-maxima of the stopbands are just 12 nm. The narrow stopbands of colloidal PCs are ascribed to the combined effects of perfectly ordered assembly structure, large-scale crack elimination, decreased void fraction, and sufficient thickness of the colloidal PCs. These properties result from a self-assembly process on a low-adhesive superhydrophobic substrate. Latex suspension on this substrate displays a receding three-phase contact line during evaporation, which releases tensile stress induced by latex shrinkage and results in complete elimination of cracks in the colloidal PCs. Furthermore, the simultaneous assembly of latex particles on the outermost layer of a spread liquid film contributes to the perfectly ordered assembly structure. This facile fabrication of centimeter-scale colloidal PCs with narrow stopbands will offer significant insights into the design and creation of novel optical devices.

A General Strategy for Assembling Nanoparticles in One Dimension

Alignment of 1D assemblies of a wide variety of nanoparticles (e.g., metal, metal oxide, semiconductor quantum dots, or organic microspheres) in one direction upon diverse substrates (including industrial silicon wafers and transparent glass plates) by a general strategy is demonstrated. This sandwich method provides an efficient way of rapidly and precisely assembling nanoparticles on a large scale (up to 10 cm × 10 cm) for device applications.

Fabrication of Nanoscale Circuits on Inkjet‐Printing Patterned Substrates

Nanoscale circuits are fabricated by assembling different conducting materials (e.g., metal nanoparticles, metal nano-wires, graphene, carbon nanotubes, and conducting polymers) on inkjet-printing patterned substrates. This non-litho-graphy strategy opens a new avenue for integrating conducting building blocks into nanoscale devices in a cost-efficient manner.

Nanoparticle Based Curve Arrays for Multirecognition Flexible Electronics.

Assembly of nanoparticles into controllable micro or nanocurve circuits by a feasible strategy is demonstrated. The curves, with various tortuosity morphologies, have tunable resistive strain sensitivity, which can be integrated into a multi-analysis flexible sensor. The curve-based sensor can run complicated facial expression recognition, and may contribute practical applications on auxiliary apparatus for skin micromotion manipulation for paraplegics.

A general patterning approach by manipulating the evolution of two-dimensional liquid foams

The evolution of gas-liquid foams has been an attractive topic for more than half a century. However, it remains a challenge to manipulate the evolution of foams, which restricts the development of porous materials with excellent mechanical, thermal, catalytic, electrical or acoustic properties. Here we report a strategy to manipulate the evolution of two-dimensional (2D) liquid foams with a micropatterned surface. We demonstrate that 2D liquid foams can evolve beyond Ostwald ripening (large bubbles always consuming smaller ones). By varying the arrangement of pillars on the surface, we have prepared various patterns of foams in which the size, shape and position of the bubbles can be precisely controlled. Furthermore, these patterned bubbles can serve as a template for the assembly of functional materials, such as nanoparticles and conductive polymers, into desired 2D networks with nanoscale resolution. This methodology provides new insights in controlling curvature-driven evolution and opens a general route for the assembly of functional materials.

Swarm Intelligence-Inspired Spontaneous Fabrication of Optimal Interconnect at the Micro/Nanoscale

A spontaneous process is demonstrated to assemble nanoparticles into an optimal interconnect, as natural systems spontaneously figure out the shortest path. The optimal interconnect leads to a 65.9% decrease in electromagnetic interference, a 17.1% decrease in delay, and a 24.5% decrease in energy-delay. It will be of great significance for interconnect fabrication of versatile electronic circuits.

Patterned photonic crystals for hiding information

Coding techniques are not only a popular strategy for information recording and communication, but also an efficient strategy for information protection. Many species in nature, such as chameleons and peacocks, demonstrate brilliant colourful appearances for camouflage, courtship or communication. The unique optical property that originates from the interaction of light with the periodic nanostructures on their surfaces, known as photonic crystals (PCs), provides an attractive candidate for coding and anti-counterfeiting. Here we present a prototype design for hiding information in photonic crystals by building a coding and encryption relationship between optical stopbands and information units. The hidden messages are protected by three different defense strategies: characteristic optical stopbands, algorithm encryption and angle-dependent encryption, which could dramatically improve the security level of the hidden information. In combination with the large coding capacity, inherent optical stability and robust fabrication process, this PC coding system has great potential for secure information storage and communication, anti-counterfeiting and massively parallelized sensors.

Programmed Coassembly of One-Dimensional Binary Superstructures by Liquid Soft Confinement

Precise control of particles co-assembly has attracted great attention for fabricating intricate structures and functional materials. However, achieving precise co-assembly of one-dimensional (1D) binary superstructures remains challenging due to the constrained thermodynamic stability and lack of general strategies to control the 1D ordered arrangement of mixed particles. Here, we propose a facile strategy to achieve programmed co-assembly of 1D binary superstructures by liquid soft confinement without particle modification or external field. It reveals that binary particles undergo stepwise confinement and programmed co-assembly in the gradually shrinking and spatially tunable liquid soft confinement. Through tuning the liquid confined space and particles composition, diverse 1D binary superstructures with precisely controlled periodicity, orientation and symmetry are achieved, which shows generality for various particles of different sizes and materials. This work provides a promising route to refined patterning and manufacturing complex materials.

Rayleigh Instability-Assisted Satellite Droplets Elimination in Inkjet Printing

Elimination of satellite droplets in inkjet printing has long been desired for high-resolution and precision printing of functional materials and tissues. Generally, the strategy to suppress satellite droplets is to control ink properties, such as viscosity or surface tension, to assist ink filaments in retracting into one drop. However, this strategy brings new restrictions to the ink, such as ink viscosity, surface tension, and concentration. Here, we report an alternative strategy that the satellite droplets are eliminated by enhancing Rayleigh instability of filament at the break point to accelerate pinch-off of the droplet from the nozzle. A superhydrophobic and ultralow adhesive nozzle with cone morphology exhibits the capability to eliminate satellite droplets by cutting the ink filament at breakup point effectively. As a result, the nozzles with different sizes (10-80 μm) are able to print more inks (1 < Z < 38), for which the nozzles are super-ink-phobic and ultralow adhesive, without satellite droplets. The finding presents a new way to remove satellite droplets via designing nozzles with super-ink-phobicity and ultralow adhesion rather than restricting the ink, which has promising applications in printing electronics and biotechnologies.

Gas/liquid interfacial manipulation by electrostatic inducing for nano-resolution printed circuits

A critical requirement for highly conductive metallic printing circuits is to obtain consecutive and high-resolution printed patterns. However, the aggregation or assembly of metallic nanocrystals in solution is usually random, which perplexes the consecutiveness and resolution of the printed circuits. In this study, we prepared consecutive nano-resolution circuits by gas/liquid interfacial manipulation. Consecutive gas/liquid interfaces were achieved by electrostatic inducing of a cationic metal ink using anionic surfactant onto the gas/liquid interface to form continuous patterns. Gas/liquid interfacial morphology was manipulated by gas/liquid/solid three phase contact line (TCL); Through controlling TCL sliding on different surfaces, submicron or nano-resolution circuits were fabricated, which showed excellent conductivity. This facile strategy showed significant potential for use in wearable electronics and high-resolution electronic circuits.