Fabrication of CdS films with superhydrophobicity by the microwave assisted chemical bath deposition

Highly Reliable Textile-Type Memristor by Designing Aligned Nanochannels

Information-processing devices are the core components of modern electronics. Integrating them into textiles is the indispensable demand for electronic textiles to form close-loop functional systems. Memristors with crossbar configuration are regarded as promising building blocks to design woven information-processing devices that seamlessly unify with textiles. However, the memristors always suffer from severe temporal and spatial variations due to the random growth of conductive filaments during filamentary switching processes. Here, inspired by the ion nanochannels across synaptic membranes, a highly reliable textile-type memristor made of Pt/CuZnS memristive fiber with aligned nanochannels, showing small set voltage variation (<5.6%) under ultralow set voltage (≈0.089 V), high on/off ratio (≈106 ), and low power consumption (0.1 nW), is reported. Experimental evidence indicate that nanochannels with abundant active S defects can anchor silver ions and confine their migrations to form orderly and efficient conductive filaments. Such memristive performances enable the resultant textile-type memristor array to have high device-to-device uniformity and process complex physiological data like brainwave signals with high recognition accuracy (95%). The textile-type memristor arrays are mechanically durable to withstand hundreds of bending and sliding deformations, and seamlessly unified with sensing, power-supplying, and displaying textiles/fibers to form all-textile integrated electronic systems for new generation human-machine interactions.

A versatile “3M” methodology to obtain superhydrophobic PDMS-based materials for antifouling applications

Fouling, including inorganic, organic, bio-, and composite fouling seriously affects our daily life. To reduce these effects, antifouling strategies including fouling resistance, release, and degrading, have been proposed. Superhydrophobicity, the most widely used characteristic for antifouling that relies on surface wettability, can provide surfaces with antifouling abilities owing to its fouling resistance and/or release effects. PDMS shows valuable and wide applications in many fields, and due to the inherent hydrophobicity, superhydrophobicity can be achieved simply by roughening the surface of pure PDMS or its composites. In this review, we propose a versatile “3M” methodology (materials, methods, and morphologies) to guide the fabrication of superhydrophobic PDMS-based materials for antifouling applications. Regarding materials, pure PDMS, PDMS with nanoparticles, and PDMS with other materials were introduced. The available methods are discussed based on the different materials. Materials based on PDMS with nanoparticles (zero-, one-, two-, and three-dimensional nanoparticles) are discussed systematically as typical examples with different morphologies. Carefully selected materials, methods, and morphologies were reviewed in this paper, which is expected to be a helpful reference for future research on superhydrophobic PDMS-based materials for antifouling applications.

Study on the Surface Properties and Aggregation Behavior of Quaternary Ammonium Surfactants with Amide Bonds

A number of techniques, including conductivity, surface tension, dynamic light scattering, transmission electron microscopy, and ¹H nuclear magnetic resonance (¹H NMR), Fourier transform infrared (FT-IR), and ¹H-¹H 2D nuclear Overhauser effect spectroscopy (¹H-¹H 2D NOESY), have been used to investigate the effect of amide bonds on the interfacial and assembly properties of a cationic surfactant, N-anilinoformylmethyl-N-cetyl-N,N-dimethyl ammonium chloride (AMC-C ₁₆ ), in aqueous solutions. The adsorption of AMC-C ₁₆ has been found to be much better than that of the conventional cationic surfactant, benzyl cetyldimethylammonium chloride (BAC-16) at the air/water interface and in solution. The surface tension measurements show the presence of two critical aggregation concentrations (CAC₁ and CAC₂) for AMC-C ₁₆ . The presence of a strong intermolecular hydrogen bond of AMC-C ₁₆ was confirmed by ¹H NMR and FT-TR. The molecular interactions of AMC-C ₁₆ were detected by ¹H-¹H 2D NOESY. The results show that the rigid group (phenyl) of AMC-C ₁₆ was partially overlapped with its alkyl chain in aqueous solution, and the possible aggregation behavior for AMC-C ₁₆ was proposed. The effects of an inorganic salt (NaCl) and an organic salt (C₆H₅COONa) to the aggregates of AMC-C ₁₆ have been discussed.

Sulfur ion concentration dependent morphological evolution of CdS thin films and its subsequent effect on photo-electrochemical performance

The sulfur ion concentration dependent morphological evolution and its subsequent effect on photo-electrochemical properties of chemically synthesized CdS thin films have been systematically investigated. The plausible growth mechanism for the morphological evolution of CdS thin films due to a change in sulfur ion concentration has been proposed. Scanning electron micrographs (SEMs) reveal that the morphology of CdS thin films has been changed from spherical grains to vertically aligned nanoflakes by systematic control of sulfur ion concentration. This article elucidates the astute relationships between precursor concentrations, reaction rate and morphological evolution. The X-ray diffraction (XRD) patterns reveal the formation of hexagonal wurtzite CdS thin films with the preferred (002) orientation for CdS nanoflakes, which is further supported by the analysis of the high resolution transmission electron micrographs (HRTEMs). Optical absorption studies show a red shift in the absorption edge with an increase in sulfur concentration. The beneficial role of nanoflake formation is easily reflected in the photo-electrochemical performance. Improved solar cell performances are observed for CdS nanoflakes grown with a sulfur to cadmium ion concentration ratio of 4 (S : Cd = 4).

Microwave-assisted chemical bath deposition process to fabricate CdS buffer layers used in Cu(In,Ga)Se2 solar cells

Development of CdS buffer layers in Cu(In,Ga)Se₂ solar cells via a microwave-assisted chemical bath deposition process.

Microwave chemistry for inorganic nanomaterials synthesis

This Feature Article gives an overview of microwave-assisted liquid phase routes to inorganic nanomaterials. Whereas microwave chemistry is a well-established technique in organic synthesis, its use in inorganic nanomaterials' synthesis is still at the beginning and far away from having reached its full potential. However, the rapidly growing number of publications in this field suggests that microwave chemistry will play an outstanding role in the broad field of Nanoscience and Nanotechnology. This article is not meant to give an exhaustive overview of all nanomaterials synthesized by the microwave technique, but to discuss the new opportunities that arise as a result of the unique features of microwave chemistry. Principles, advantages and limitations of microwave chemistry are introduced, its application in the synthesis of different classes of functional nanomaterials is discussed, and finally expected benefits for nanomaterials' synthesis are elaborated.

Preparation of superhydrophobic surfaces of hierarchical structure of hybrid from nanoparticles and regular pillar-like pattern

The hierarchical structure silica surface of inlaying silica nanoparticles along a regular pillar-like pattern is fabricated by embossing silica sol-gel precursor mixed with silica nanoparticles on glass substrates with an elastomeric mold. The substrate is further modified by a self-assembled fluorosilanated monolayer to reduce its surface energy. The advancing/receding contact angle measurements are performed to demonstrate that a water droplet on these surfaces can exhibit a transition from the Wenzel state to the Cassie state due to the addition of silica nanoparticles to enhance its surface roughness.

Interfacial self-assembled fabrication of petal-like CdS/ dodecylamine hybrids toward enhanced photoluminescence

We report a new available strategy for fabricating 2-dimensional petal-like CdS/dodecylamine (DDA) hybrids with enhanced photoluminescence (PL) by using a method of oil/water interfacial self-assembly. First, water-soluble CdS nanocrystals (NCs) were controllably prepared at the two-phase interface by injecting the Na2S solution into CCl4 phase. And then, the as-synthesized CdS NCs (ca. 4 nm) were transferred from the water to the CHCl3 phase under the direction of DDA. Finally, through the electrostatic interactions between the positively charged amino of DDA and the negatively charged the ligand of NCs surface, we have successfully fabricated petal-like CdS/DDA hybrids via the interfacial self-assembly between the as-synthesized CdS NCs and DDA. The properties of as-prepared CdS NCs and their hybrids were thoroughly investigated by ultraviolet-visible (UV-vis), transmission electron microscope (TEM), Fourier transform infrared spectra (FT-IR), photoluminescence (PL), scanning electron microscopy (SEM) measurements. We have found that these petal-like CdS/DDA hybrids after interfacial self-assembly exhibit good PL property and higher quantum yield.