Xue Zhou

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.

Wearable Large‐Scale Perovskite Solar‐Power Source via Nanocellular Scaffold

Dramatic advances in perovskite solar cells (PSCs) and the blossoming of wearable electronics have triggered tremendous demands for flexible solar-power sources. However, the fracturing of functional crystalline films and transmittance wastage from flexible substrates are critical challenges to approaching the high-performance PSCs with flexural endurance. In this work, a nanocellular scaffold is introduced to architect a mechanics buffer layer and optics resonant cavity. The nanocellular scaffold releases mechanical stresses during flexural experiences and significantly improves the crystalline quality of the perovskite films. The nanocellular optics resonant cavity optimizes light harvesting and charge transportation of devices. More importantly, these flexible PSCs, which demonstrate excellent performance and mechanical stability, are practically fabricated in modules as a wearable solar-power source. A power conversion efficiency of 12.32% for a flexible large-scale device (polyethylene terephthalate substrate, indium tin oxide-free, 1.01 cm2 ) is achieved. This ingenious flexible structure will enable a new approach for development of wearable electronics.

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.

Strong Photonic-Band-Gap Effect on the Spontaneous Emission in 3D Lead Halide Perovskite Photonic Crystals

Stimulated emission in perovskite-embedded polymer opal structures is investigated. A polymer opal structure is filled with a perovskite, and perovskite photonic crystals are prepared. The spontaneous emission of the perovskite embedded in the polymer opal structures exhibits clear signatures of amplified spontaneous emission (ASE) via gain modulation. The difference in refractive-index contrast between the perovskite and the polymer opal is large enough for retaining photonic-crystals properties. The photonic band gap has a strong effect on the fluorescence emission intensity and lifetime. The stimulated emission spectrum exhibits a narrow ASE rather than a wide fluorescence peak in the thin film.

Printable Skin‐Driven Mechanoluminescence Devices via Nanodoped Matrix Modification

Mechanically driven light generation is an exciting and under-exploited phenomenon with a variety of possible practical applications. However, the current driving mode of mechanoluminescence (ML) devices needs strong stimuli. Here, a flexible sensitive ML device via nanodopant elasticity modulus modification is introduced. Rigid ZnS:M2+ (Mn/Cu)@Al2 O3 microparticles are dispersed into soft poly(dimethylsiloxane) (PDMS) film and printed out to form flexible devices. For various flexible and sensitive scenes, SiO2 nanoparticles are adopted to adjust the elasticity modulus of the PDMS matrix. The doped nanoparticles can concentrate stress to ZnS:M2+ (Mn/Cu)@Al2 O3 microparticles and achieve intense ML under weak stimuli of the moving skin. The printed nano-/microparticle-doped matrix film can achieve skin-driven ML, which can be adopted to present fetching augmented animations expressions. The printable ML film, amenable to large areas, low-cost manufacturing, and mechanical softness will be versatile on stress visualization, luminescent sensors, and open definitely new functional skin with novel augmented animations expressions, the photonic skin.