Advanced Materials Interfaces最新文献

The manipulation of droplets and wetting properties is crucial in many applications that involve surface-liquid interactions, especially on artificial superhydrophobic substrates. This study presents an active optoelectronic method to achieve transport and transition between two wetting states on patterned surfaces, namely Cassie–Baxter (CB) and Wenzel (W). The approach employs a photovoltaic iron-doped lithium niobate crystal placed on the bottom of a micropatterned substrate without any adhesive or sticky bonding. Taking advantage of the bulk photovoltaic effect, charge separation can be induced by light inside the crystal, thus leading to virtual electrodes. The long-range interaction between these virtual electrodes and the droplets on the top of the substrate allows for transitions between wetting states and droplet transport. Superhydrophobic wetting transitions between Cassie–Baxter and Wenzel are observed on different substrates using this technique. The forces acting on the droplet that cause the transition are determined numerically. The evolution of droplet deformation and contact angle during the generation of the virtual electrode depends on the shape and intensity of the light beam used for photoinduction, as well as on the compositional properties of the crystal.

The application of photoelectrochemical cells to the partial oxidation of biomass represents a promising avenue as a sustainable process for obtaining valuable products. However, achieving both efficient conversion rates and high selectivity of desired products remains a great challenge. In this study, the photoelectrochemical oxidation of glycerol is investigated to produce dihydroxyacetone (DHA) as the primary target using TiO₂ nanotubes (NTs) as the photoanode. Nitrogen doping is used to modify the TiO₂ NTs, resulting in enhanced visible light photoactivity in N-doped NTs. These N-doped NTs exhibit a high selectivity toward DHA and show a remarkable faradaic efficiency when irradiated with light at a wavelength of 450 nm, i.e., light that excites N-related states in the band gap of TiO₂. The N-doped material also exhibits remarkable stability over prolonged reaction periods. The superior performance of N-doped NTs can be attributed to the band-engineering effects induced by nitrogen doping. Specifically, N-doping leads to an upward shift of the valence band, thereby adjusting the exit energy levels of photogenerated holes that result in a high selectivity toward glycerol conversion to DHA.

This study investigates the fabrication of organic solvent nanofiltration (OSN) membranes through laser-induced graphitization of polybenzimidazole (PBI). Employing a CO2 laser, the polymer is converted into graphene, resulting in controlled submicron-scale porous 3D structures, a feat not achievable with traditional methods such as chemical crosslinking. The effectiveness of this process hinges on precise adjustments of laser parameters, such as fluence, to attain the ideal graphitization levels. The findings indicate that partial graphitization, as opposed to excessive, is crucial for preserving the membrane's microstructure and enhancing its functional properties. The partially graphitized PBI-LIG (Polybenzimidazole ‒ Laser-induced Graphene) membranes achieved up to 94% rejection of Congo red from ethanol, with an ethanol permeance rate of 12.14 LMH bar⁻¹—nearly twice that of standard PBI membranes. Additionally, these membranes showcased outstanding chemical stability and solvent resistance, maintaining over 99% structural integrity and experiencing <1% weight loss after prolonged exposure to various industrial solvents over a week. These results highlight the potential of laser-graphitized PBI membranes for applications in harsh chemical conditions, paving the way for further optimization of high-performance OSN membranes. This research advances membrane technology, merging laser engineering with materials science, and contributes to environmental sustainability and industrial efficiency.

Metal fluoride thin films are important materials in a multitude of applications. Currently, they are mostly used in optics, but their potential in energy harvesting and storage is recognized as well. Atomic layer deposition (ALD) is an advanced thin film deposition method that has an ever-increasing role in microelectronics. The assets of ALD are its capability to produce uniform, stoichiometric, and pure films with precise thickness control even on top of complicated structures, such as high aspect ratio trenches. These characteristics can be beneficial in applications of metal fluoride thin films but so far ALD of metal fluorides has remained much less studied and used than ALD of metal oxides, nitrides, sulfides, and pure metals. This review aims to motivate research on ALD of metal fluorides by surveying potential applications for ALD metal fluoride thin films and coatings. The basics of luminescent applications, antireflection coatings, and lithium-ion batteries will be discussed. Next, the fundamentals of ALD will be presented followed by a comprehensive summary of the metal fluoride ALD processes published so far.

Antimicrobial materials are crucial for high-touch surfaces to prevent the adhesion and proliferation of microorganisms, playing a key role in infection control measures. In this work, a magnetoelectric nanocomposite able to exert antimicrobial activity when magnetically stimulated, is obtained by solvent casting. The nanocomposites, composed of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and cobalt ferrite magnetostrictive nanoparticles (CFO NPs), respond to a variable magnetic field by mechanically stimulating the piezoelectric component of the material, thereby inducing an electrical polarization. The antimicrobial properties of the material are determined by exposing it to different frequencies (0.3 and 1 Hz) using a custom-designed magnetic bioreactor, where the resulting electrical microenvironments are the contributing factor. The growth of Escherichia coli and Staphylococcus aureus over the nanocomposite is highly inhibited when magnetically stimulated (dynamic conditions) mainly at 0.3 Hz, in contrast to static conditions. The electric microenvironment is further measured upon magnetic stimulation, with PHBV films with 20% CFO inducing a voltage variation of ≈20 µV at the surface while the films with 10% CFO induced a voltage variation of ≈12 µV. This work demonstrated that magnetic stimulation, combined with magnetoelectric materials, can be used for remote antimicrobial control, thus preventing the spread of infections.

One of the remaining challenges for lithium–sulfur batteries toward practical application is early cathode passivation by the insulating discharge product: Li₂S. To understand how to best mitigate passivation and minimize related performance loss, a kinetic Monte–Carlo model for Li₂S crystal growth from solution is developed. The key mechanisms behind the strongly different natures of Li₂S layer growth, structure, and morphology for salts with different (DN) are revealed. LiTFSI electrolyte in dimethyl ether leads to lateral Li₂S growth on carbon and fast passivation because it increases the Li₂S precipitation-to-dissolution probability on carbon relative to Li₂S. In contrast, LiBr electrolyte has a higher DN and yields a particle-like structure due to a significantly higher precipitation-to-dissolution probability on Li₂S compared to carbon. The resulting large number of Li₂S sites further favors particle growth, leading to low passivation. This study is able to identify the key parameters of the electrolyte and substrate material to tune Li₂S morphology and growth to pave the way for optimized performance.

Full-Color Retinal Prosthetic

Optoelectronic organic polymers are employed as functional material substitutes for photoreceptor cells towards a state-of-the-art full-color retinal prosthetic with the aim of potentially restoring vision in individuals afflicted with retinal disorders such as age-related macular degeneration and retinitis pigmentosa. More details can be found in article 2400128 by Leslie Askew, Aimee Sweeney, David Cox, and Maxim Shkunov.

Defect Engineering

Thanks to the existence of photo-active defect states in h-BN, an effective type-II band alignment between h-BN and WS₂ monolayer is formed under 520 laser irradiations. In article 2400288 by Xue Liu and co-workers, such lattice defects were intentionally introduced in the h-BN layer by controlled inductively coupled plasma (ICP) treatment, which provide more driving force for the separation of electron-hole pairs in WS₂ under laser irradiation, and promote the motion of charge carriers at the WS₂/ h-BN interface.

Wurtzite-(Al,Sc)N films are promising candidates for ferroelectric memory devices owing to their outstanding properties. However, there are many challenges on the way to practical applications, including lowering an electric field required for polarization switching. Understanding the switching kinetics, especially the starting point of polarization reversal, is key to designing materials with desired properties. Here, the impact of Sc concentration and segregation on the switching kinetics for (Al,Sc)N capacitors is investigated by evaluating time- and field-dependences of the switching polarization for the tri-layered (Al,Sc)N films with various Sc/(Al+Sc) ratios. The remanent polarization of stacked films slightly decreased compared to those of the single-layered films with the same average Sc/(Al+Sc) ratio, while their coercive fields depended on the average Sc content in (Al,Sc)N. The ferroelectric switching behavior suggests the possibility of nucleation originating from the Sc-rich region and the sequential switching mechanism for individual layers, which is unique to multilayered films. This shows a possibility that nucleations of the polarization switching start not from the interface between the (Al,Sc)N films and the electrodes. The unique switching kinetics in tri-layered (Al,Sc)N films have provided new insights into the field of ferroelectric switching in wurtzite-nitrides.