Enhanced Thermal Stability of Conductive Mercury Telluride Colloidal Quantum Dot Thin Films Using Atomic Layer Deposition.

Colloidal quantum dots (CQDs) are valuable for their potential applications in optoelectronic devices. However, they are susceptible to thermal degradation during processing and while in use. Mitigating thermally induced sintering, which leads to absorption spectrum broadening and undesirable changes to thin film electrical properties, is necessary for the reliable design and manufacture of CQD-based optoelectronics.

Infrared phase-change chiral metasurfaces with tunable circular dichroism.

Integrating phase-change materials in metasurfaces has emerged as a powerful strategy to realize optical devices with tunable electromagnetic responses. Here, phase-change chiral metasurfaces based on GST-225 material with the designed trapezoid-shaped resonators are demonstrated to achieve tunable circular dichroism (CD) responses in the infrared regime. The asymmetric trapezoid-shaped resonators are designed to support two chiral plasmonic resonances with opposite CD responses for realizing switchable CD between negative and positive values using the GST phase change from amorphous to crystalline.

Wavelength-tunable infrared chiral metasurfaces with phase-change materials.

Optical phase-change materials exhibit tunable permittivity and switching properties during phase transition, which offers the possibility of dynamic control of optical devices. Here, a wavelength-tunable infrared chiral metasurface integrated with phase-change material GST-225 is demonstrated with the designed unit cell of parallelogram-shaped resonator. By varying the baking time at a temperature above the phase transition temperature of GST-225, the resonance wavelength of the chiral metasurface is tuned in the wavelength range of 2.

Operando study of mechanical integrity of high-volume expansion Li-ion battery anode materials coated by AlO.

Group IV elements and their oxides, such as Si, Ge, Sn and SiO have much higher theoretical capacity than commercial graphite anode. However, these materials undergo large volume change during cycling, resulting in severe structural degradation and capacity fading. AlOcoating is considered an approach to improve the mechanical stability of high-capacity anode materials.

Digital Twin and web services for robotic deburring in intelligent manufacturing.

The development of modern manufacturing requires key solutions to enhance the intelligence of manufacturing such as digitalization, real-time monitoring, or simulation techniques. For smart robotic manufacturing, the modern approach regarding robot programming and process planning aims for both high efficiency and energy-awareness. During the design and manufacturing stages, optimization becomes crucial and can be fulfilled by means of appropriate digital manufacturing tools.

High-Throughput Microfluidics Platform for Intracellular Delivery and Sampling of Biomolecules from Live Cells.

Nondestructive cell membrane permeabilization systems enable the intracellular delivery of exogenous biomolecules for cell engineering tasks as well as the temporal sampling of cytosolic contents from live cells for the analysis of dynamic processes. Here, we report a format live-cell analysis device (LCAD) that can perform localized-electroporation induced membrane permeabilization, for cellular delivery or sampling, and directly interfaces with surface-based biosensors for analyzing the extracted contents. We demonstrate the capabilities of the LCAD via an automated high-throughput workflow for multimodal analysis of live-cell dynamics, consisting of quantitative measurements of enzyme activity using self-assembled monolayers for MALDI mass spectrometry (SAMDI) and deep-learning enhanced imaging and analysis.

The Effect of Periodic Spatial Perturbations on the Emission Rates of Quantum Dots near Graphene Platforms.

The quenching of fluorescence (FL) at the vicinity of conductive surfaces and, in particular, near a 2-D graphene layer has become an important biochemical sensing tool. The quenching is attributed to fast non-radiative energy transfer between a chromophore (here, a Quantum Dot, QD) and the lossy graphene layer. Increased emission rate is also observed when the QD is coupled to a resonator.

Approaching the Strain-Free Limit in Ultrathin Nanomechanical Resonators.

Ultrathin mechanical structures are ideal building platforms to pursue the ultimate limit of nanomechanical resonators for applications in sensing, signal processing, and quantum physics. Unfortunately, as the thickness of the vibrating structures is reduced, the built-in strain of the structural materials plays an increased role in determining the mechanical performance of the devices. As a consequence, it is very challenging to fabricate resonators working in the modulus-dominant regime, where their dynamic behavior is exclusively determined by the device geometry.

Optimized oxygen deprived low temperature sputtered WO thin films for crystalline structures.

We report a detailed analysis on the effects of processing parameters for sputtered tungsten trioxide (WO) thin nanoscale films on their structural, vibrational and electrical properties. The research aims to understand the fundamental aspects of WO sputtering at relatively low temperatures and in an oxygen deprived environment targeting applications of temperature and oxygen sensitive substrates. Structural analysis indicates that films deposited at room temperature, or substrate temperatures at or below 400 °C with low oxygen partial pressure are amorphous.

Broadband infrared binary-pattern metasurface absorbers with micro-genetic algorithm optimization.

Broadband binary-pattern metasurface absorbers are designed and demonstrated in the mid-infrared wavelength range through the micro-genetic algorithm. The tungsten-based metasurface absorbers with the optimized binary-pattern nanostructures exhibit broadband near-perfect absorption due to the multiple plasmonic resonances supported within the unit cell. Furthermore, the influence of minor pixel modifications in the optimized binary-pattern nanostructures on the absorption performance is investigated in the experiment.

Quantitative Observation of Threshold Defect Behavior in Memristive Devices with Operando X-ray Microscopy.

Memristive devices are an emerging technology that enables both rich interdisciplinary science and novel device functionalities, such as nonvolatile memories and nanoionics-based synaptic electronics. Recent work has shown that the reproducibility and variability of the devices depend sensitively on the defect structures created during electroforming as well as their continued evolution under dynamic electric fields. However, a fundamental principle guiding the material design of defect structures is still lacking due to the difficulty in understanding dynamic defect behavior under different resistance states.

Reconfigurable Vanadium Dioxide Nanomembranes and Microtubes with Controllable Phase Transition Temperatures.

Two additional structural forms, free-standing nanomembranes and microtubes, are reported and added to the vanadium dioxide (VO) material family. Free-standing VO nanomembranes were fabricated by precisely thinning as-grown VO thin films and etching away the sacrificial layer underneath. VO microtubes with a range of controllable diameters were rolled-up from the VO nanomembranes.

Wavelength-selective mid-infrared metamaterial absorbers with multiple tungsten cross resonators.

Wavelength-selective metamaterial absorbers in the mid-infrared range are demonstrated by using multiple tungsten cross resonators. By adjusting the geometrical parameters of cross resonators in single-sized unit cells, near-perfect absorption with single absorption peak tunable from 3.5 µm to 5.

Single-Crystalline SrRuO3 Nanomembranes: A Platform for Flexible Oxide Electronics.

The field of oxide electronics has benefited from the wide spectrum of functionalities available to the ABO3 perovskites, and researchers are now employing defect engineering in single crystalline heterostructures to tailor properties. However, bulk oxide single crystals are not conducive to many types of applications, particularly those requiring mechanical flexibility. Here, we demonstrate the realization of an all-oxide, single-crystalline nanomembrane heterostructure.

Enhanced structural color generation in aluminum metamaterials coated with a thin polymer layer.

A high-resolution and angle-insensitive structural color generation platform is demonstrated based on triple-layer aluminum-silica-aluminum metamaterials supporting surface plasmon resonances tunable across the entire visible spectrum. The color performances of the fabricated aluminum metamaterials can be strongly enhanced by coating a thin transparent polymer layer on top. The results show that the presence of the polymer layer induces a better impedance matching for the plasmonic resonances to the free space so that strong light absorption can be obtained, leading to the generation of pure colors in cyan, magenta, yellow and black (CMYK) with high color saturation.

Aluminum plasmonic metamaterials for structural color printing.

We report a structural color printing platform based on aluminum plasmonic metamaterials supporting near perfect light absorption and narrow-band spectral response tunable across the visible spectrum to realize high-resolution, angle-insensitive color printing with high color purity and saturation. Additionally, the fabricated metamaterials can be protected by a transparent polymer thin layer for ambient use with further improved color performance. The demonstrated structural color printing with aluminum plasmonic metamaterials offers great potential for relevant applications such as security marking and information storage.

Broadband perfect absorber based on one ultrathin layer of refractory metal.

Broadband perfect absorber based on one ultrathin layer of the refractory metal chromium without structure patterning is proposed and demonstrated. The ideal permittivity of the metal layer for achieving broadband perfect absorption is derived based on the impedance transformation method. Since the permittivity of the refractory metal chromium matches this ideal permittivity well in the visible and near-infrared range, a silica-chromium-silica three-layer absorber is fabricated to demonstrate the broadband perfect absorption.

Tailoring the morphology of carbon nanotube arrays: from spinnable forests to undulating foams.

Directly spinning carbon nanotube (CNT) fibers from vertically aligned CNT arrays is a promising way for the application of CNTs in the field of high-performance materials. However, most of the reported CNT arrays are not spinnable. In this work, by controlling catalyst pretreatment conditions, we demonstrate that the degree of spinnability of CNTs is closely related to the morphology of CNT arrays.