Optical Evidence of Interfacial Strain-Induced Ferroelectric Tuning and Enhancement in CuInPS via Ferroelectric Substrate.

The precise domain control in ferroelectric CuInPS (CIPS) remains challenging. A promising approach is by interfacing CIPS with the ferroelectric layer, but interface-driven ferroelectricity tunning mechanism remains unclear. Here, the demonstration of interfacial strain-induced ferroelectric tuning and enhancement in CIPS via ferroelectric substrate is reported by photoluminescence (PL) spectroscopy, combined with piezoresponse force microscopy (PFM) and density functional theory (DFT) calculations.

Controlled Fabrication of Wafer-Scale, Flexible Ag-TiO Nanoparticle-Film Hybrid Surface-Enhanced Raman Scattering Substrates for Sub-Micrometer Plastics Detection.

As an important trace molecular detection technique, surface-enhanced Raman scattering (SERS) has been extensively investigated, while the realization of simple, low-cost, and controllable fabrication of wafer-scale, flexible SERS-active substrates remains challenging. Here, we report a facile, low-cost strategy for fabricating wafer-scale SERS substrates based on Ag-TiO nanoparticle-film hybrids by combining dip-coating and UV light array photo-deposition. The results show that a centimeter-scale Ag nanoparticle (AgNP) film (~20 cm × 20 cm) could be uniformly photo-deposited on both non-flexible and flexible TiO substrates, with a relative standard deviation in particle size of only 5.

Construction of Chiral-Magnetic-Dielectric Trinity Structures with Different Magnetic Systems for Efficient Low-Frequency Microwave Absorption.

The fabrication of carbon nanocoil (CNC)-based chiral-dielectric-magnetic trinity composites holds great significance in low-frequency microwave absorption fields. However, it is not clear that how the different magnetic systems affect the magnetic and frequency responses of the composites. Herein, four types of magnetic metals, FeCo, CoNi, FeNi, and FeCoNi, are selected to be combined with the chiral templates respectively, resulting in four types of chiral-dielectric-magnetic composites with similar morphology.

Precise Crystal Orientation Identification and Twist-Induced Giant Modulation of Optical Anisotropy in 1T'-ReS.

The ability to precisely identify crystal orientation as well as to nondestructively modulate optical anisotropy in atomically thin rhenium dichalcogenides is critical for the future development of polarization programmable optoelectronic devices, which remains challenging. Here, we report a modified polarized optical imaging (POI) method capable of simultaneously identifying in-plane (Re chain) and out-of-plane (-axis) crystal orientations of the monolayer to few-layer ReS, meanwhile, propose a nondestructive approach to modulate the optical anisotropy in ReS via twist stacking. The results show that parallel and near-cross POI are effective to independently identify the in-plane and out-of-plane crystal orientations, respectively, while regulating the twist angle allows for giant modulation of in-plane optical anisotropy from highly intrinsic anisotropy to complete optical isotropy in the stacked ReS bilayer (with either the same or opposite axes), as well modeled by linear electromagnetic theory.

A microfluidics vapor-membrane-valve generated by laser irradiation on carbon nanocoils.

We have investigated a micro vapor membrane valve (MVMV) for closing the microfluidic channels by laser irradiation on carbon nanocoils (CNCs) attached to the inner wall of the microchannels. The microchannel with MVMVs was found to exhibit a "closed" state without the supply of laser energy, which is explained on the basis of the theory of heat and mass transfer. Multiple MVMVs for sealing the channels can be generated in sequence and exist simultaneously at different irradiation sites, independently.

Hierarchical and Porous Structures of Carbon Nanotubes-Anchored MOF Derivatives Bridged by Carbon Nanocoils as Lightweight and Broadband Microwave Absorbers.

High-performance microwave absorption (MA) materials have attracted more and more attention because they can effectively prevent microwave radiation and interference from electronic devices. Herein, a new type of MA composite is constructed by introducing carbon nanotubes (CNTs)-anchored metal-organic framework derivatives (MOFDs) into a conductive carbon nanocoil (CNC) network, denoted as CNC/CNT-MOFD. The CNC/MOFD shows a wide effective absorption band of 6.

MOF-derived AuNS/LDH with high adsorption ability for surface enhanced Raman spectroscopy detection.

The sensitivity of surface enhanced Raman spectroscopy (SERS) depends on the construction of "hot spots" and the number of analyte molecules adsorbed onto the substrates. Herein, we have constructed a kind of SERS substrate based on gold nanostars (Au NSs) coated with nickel-cobalt layered double hydroxide (LDH) using a zeolitic imidazolate skeleton as sacrificial template via nickel ions etching. LDH was used as the absorption medium for target molecules, and concurrently prevented Au NSs from agglomeration to improve stability and uniformity of the substrate.

Fabrication and Conductive Mechanism Analysis of Stretchable Electrodes Based on PDMS-Ag Nanosheet Composite with Low Resistance, Stability, and Durability.

A flexible and stretchable electrode based on polydimethylsiloxane (PDMS)-Ag nanosheet composite with low resistance and stable properties has been investigated. Under the synergistic effect of the excellent flexibility and stretchability of PDMS and the excellent electrical conductivity of Ag nanosheets, the electrode possesses a resistivity as low as 4.28 Ωm, a low resistance variation in the 0-50% strain range, a stable electrical conductivity over 1000 cycles, and a rapid recovery ability after failure caused by destructive large stretching.

Construction of a binder-free non-enzymatic glucose sensor based on Cu@Ni core-shell nanoparticles anchored on 3D chiral carbon nanocoils-nickel foam hierarchical scaffold.

Bimetallic nanostructures composited with carbonaceous materials are the potential contenders for quantitative glucose measurement owing to their unique nanostructures, high biomimetic activity, synergistic effects, good conductivity and chemical stability. In the present work, chemical vapors deposition technique has been employed to grow 3D carbon nanocoils (CNCs) with a chiral morphology on hierarchical macroporous nickel foam (NF) to get a CNCs/NF scaffold. Following, bimetallic Cu@Ni core-shell nanoparticles (CSNPs) are effectively coupled with this scaffold through a facile solvothermal route in order to fabricate a binder-free novel Cu@Ni CSNPs/CNCs/NF hybrid nanostructure.

A flexible tissue-carbon nanocoil-carbon nanotube-based humidity sensor with high performance and durability.

A flexible humidity sensor based on a tissue-carbon nanocoil (CNC)-carbon nanotube (CNT) composite has been investigated. Taking advantage of the excellent water absorption of tissue and the electrical sensitivity of CNCs/CNTs to humidity, this humidity sensor obtains outstanding humidity sensing performance, including a wide sensing range of 10-90% RH, a maximum response value of 492% (Δ/) at 90% RH, a maximum sensitivity of 6.16%/% RH, a good long-time stability of more than 7 days, a high humidity resolution accuracy of less than 1% RH and a fast response time of 275 ms.

Novel Wearable Pyrothermoelectric Hybrid Generator for Solar Energy Harvesting.

Recently, wearable energy harvesting systems have been attracting great attention. As thermal energy is abundant in nature, developing wearable energy harvesters based on thermal energy conversion processes has been of particular interest. By integration of a high-efficient solar absorber, a pyroelectric film, and thermoelectric yarns, herein, we design a novel wearable solar-energy-driven pyrothermoelectric hybrid generator (PTEG).

Surface modification of helical carbon nanocoil (CNC) with N-doped and Co-anchored carbon layer for efficient microwave absorption.

Surface modification and composition control for nanomaterials are effective strategies for designing high-performance microwave absorbing materials (MWAMs). Herein, we have successfully fabricated Co-anchored and N-doped carbon layers on the surfaces of helical carbon nanocoils (CNCs) by wet chemical and pyrolysis methods, denoted as Co@N-Carbon/CNCs. It is found that pure CNCs show a very good microwave absorption performance under a filling ratio of only 6%, which is attributed to the uniformly dispersed conductive network and the cross polarization induced by the unique chiral and spiral morphology.

Flexible, Transparent and Highly Conductive Polymer Film Electrodes for All-Solid-State Transparent Supercapacitor Applications.

Lightweight energy storage devices with high mechanical flexibility, superior electrochemical properties and good optical transparency are highly desired for next-generation smart wearable electronics. The development of high-performance flexible and transparent electrodes for supercapacitor applications is thus attracting great attention. In this work, we successfully developed flexible, transparent and highly conductive film electrodes based on a conducting polymer, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS).

Carbon nanocoils decorated with a porous NiCoO nanosheet array as a highly efficient electrode for supercapacitors.

Well-organized substrate materials are of considerable significance in the development of energy-efficient pseudocapacitor electrodes. Herein, functionalized three-dimensional (3D) carbon nanocoils on nickel foam (CNCs/NF) have been used as the substrate to grow faradaic nickel cobaltite (NiCo2O4) via a solvothermal method. The arrays of NiCo2O4 were assembled by interconnected ultrathin nanosheets with random inter-particle pores.

Structural Engineering of Hierarchical Aerogels Comprised of Multi-dimensional Gradient Carbon Nanoarchitectures for Highly Efficient Microwave Absorption.

Recently, multilevel structural carbon aerogels are deemed as attractive candidates for microwave absorbing materials. Nevertheless, excessive stack and agglomeration for low-dimension carbon nanomaterials inducing impedance mismatch are significant challenges. Herein, the delicate "3D helix-2D sheet-1D fiber-0D dot" hierarchical aerogels have been successfully synthesized, for the first time, by sequential processes of hydrothermal self-assembly and in-situ chemical vapor deposition method.

Self-healing and anti-freezing graphene-hydrogel-graphene sandwich strain sensor with ultrahigh sensitivity.

Hydrogels with specially designed structures and adjustable properties have been considered as smart materials with multi-purpose application prospects, especially in the field of flexible sensors. However, most hydrogel-based sensors have low sensitivity, which inevitably affects their promotion in the market. Herein, a strain sensor comprising a poly(vinyl alcohol)/poly(acrylic acid) (PVA/PAA) hybrid hydrogel sandwiched between two graphene layers was successfully constructed in a facile way, and it exhibited many excellent properties including extremely high sensitivity.

Tip-to-tip assembly of urchin-like Au nanostar at water-oil interface for surface-enhanced Raman spectroscopy detection.

Au Nanostar (NS) monolayer as a surface enhanced Raman scattering (SERS) substrate has been synthesized by self-assembly at a water-oil interface. It is confirmed from the experiment and simulation results that the Au NS monolayer includes lots of "hot spots" at or between the tips of the Au NSs, enhancing the local electromagnetic fields and giving rise to strong SERS signals sequentially. The limit of detection is determined to be down to 4.

Highly Flexible, Stretchable, and Self-Powered Strain-Temperature Dual Sensor Based on Free-Standing PEDOT:PSS/Carbon Nanocoils-Poly(vinyl) Alcohol Films.

The wearable and self-powered sensors with multiple functions are urgently needed for energy saving devices, economical convenience, and artificial human skins. It is a meaningful idea to convert excess heat sources into power supplies for wearable sensors. In this report, we have fabricated a series of free-standing self-powered temperature-strain dual sensors based on poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS)/carbon nanocoils (CNCs)-poly(vinyl) alcohol composite films by a simple drop casting method.

A Facile Synthesis of Novel Amorphous TiO Nanorods Decorated rGO Hybrid Composites with Wide Band Microwave Absorption.

Amorphous structures may play important roles in achieving highly efficient microwave absorption performance due to the polarization losses induced by the disorders, vacancies and other functional groups existed in them. Herein, a kind of amorphous TiO/rGO composite (a-TiO/rGO) was successfully fabricated via a facile one-step solvothermal method. The complex permittivity of the composites can be regulated by adjusting the addition of precursor solution.

Facile Fabrication of High-Performance Pen Ink-Decorated Textile Strain Sensors for Human Motion Detection.

Recently, wearable strain sensors have increasingly attracted much attention due to their potential applications in human motion detection and personal health monitoring. To date, it is still a challenge to fabricate a flexible strain sensor with both comfort and high performance. In this study, we dip the commercially available spandex/polyamide fabric into carbonic pen ink to prepare a textile strain sensor with good skin affinity.

Reduced holey graphene oxide film and carbon nanotubes sandwich structure as a binder-free electrode material for supercapcitor.

A novel carbon nanotubes (CNTs) and reduced holey graphene oxide film (RHGOF) sandwich structure has been fabricated to enhance its electrochemical properties. CNTs are grown by a catalyst assisted chemical vapor deposition technique, interpenetrated between the RHGOF layers. A RHGOF/CNTs hybrid film is used as a binder-free supercapacitor electrode.

A carbon nanocoil-based flexible tip for a live cell study of mechanotransduction and electro-physiological characteristics.

The responses of living cells to external mechanical and electrical stimulation play important roles in regulating their biological functions and behaviors, and the response mechanisms have attracted great attention. Global stimulation on cells is generally used in traditional methods, but it is insufficient to investigate the mechanism of a dynamic physiological response at the subcellular level. At present, there is still lack of a low-cost and easy-operated method to apply local mechanical force and electrical stimulation on living cells.

Growth of Carbon Nanocoils by Porous α-FeO/SnO Catalyst and Its Buckypaper for High Efficient Adsorption.

High-purity (99%) carbon nanocoils (CNCs) have been synthesized by using porous α-FeO/SnO catalyst. The yield of CNCs reaches 9,098% after a 6 h growth. This value is much higher than the previously reported data, indicating that this method is promising to synthesize high-purity CNCs on a large scale.