ACS Applied Materials & Interfaces最新文献

Expanding material types and developing two-dimensional (2D) semiconductor materials with high performance have been hotspots in the field. In this research, it is found that the 12 existing semiconductors A₂BXY₂ (A = K, Na; B = Li, Na; X = Al, Ga, In; Y = P, As, Sb) have a pronounced layered structure. We predict their 2D structures and properties, using first-principles calculations. Lower exfoliation energies confirm the feasibility of mechanical exfoliation from their bulk phases and that the 2D structures can be stabilized independently at room temperature. Interestingly, A₂BXY₂ has an anionic tetrahedral one-dimensional chain or two-dimensional mesh structure of [XY₂]^3- composed of elements III-V. All A₂BXY₂ monolayers exhibit direct or indirect band gap features (0.78-1.94 eV). More encouragingly, the A₂BXY₂ monolayers possess ultrahigh carrier mobilities (∼10⁵ cm² V^-1 s^-1) at room temperature. Furthermore, the results based on the nonequilibrium Green's function indicate that 2D A₂BXY₂ exhibits a high ON/OFF ratio (∼10⁴). To sum up, the A₂BXY₂ family is an outstanding promising candidate for optoelectronics application.

The sensing of phthalate esters (PAEs) is vital for people's health and environmental protection. This study aimed to develop a highly sensitive and selective photoelectrochemical (PEC) biosensor for PAEs analysis in complex samples. The biosensor is based on a CdS nanoparticle/TiO₂ nanotube (CdS NP/TiO₂ NT) electrode substrate and a truncated PAEs aptamer (PAEs-apt). By exploiting spatial variations in the potential resistance of the sensing interface, the biosensor achieved superior sensitivity in determining the concentration of PAEs compared to the SELEX aptamer. It exhibited a linear correlation in the range of 0.005 to 1 ng/mL with a detection limit of 1.67 ng/L. Furthermore, the biosensor displayed excellent selectivity for PAEs, with an analysis error factor below 0.277 when the concentration of interfering species was 100 times that of the target. The high performance of the biosensor was attributed to the excellent photoelectronic properties of CdS NPs/TiO₂ NTs, high density of PAEs-apt for PAEs, high affinity of PAEs-apt for PAEs, and specific recognition of PAEs. Notably, this PEC biosensor could be used for the PAEs assay in urine and water samples, providing a sensitive and simple analytical method for detecting the same class of compounds with similar chemical structures in complex samples.

Ionic thermoelectric materials, renowned for their high Seebeck coefficients, are gaining prominence for their potential in harvesting low-grade waste heat. However, the theoretical underpinnings for enhancing the performance of these materials remain underexplored. In this study, the Hoffmeister effect was leveraged to augment the thermoelectric properties of hydrogel-based ionic thermoelectric materials. A series of PAAm-x Zn(CF₃SO₃)₂, PAAm-x ZnSO₄, and PAAm-x Zn(ClO₄)₂ hydrogels were synthesized, using polyacrylamide (PAAm) as the matrix and three distinct zinc salts with varying anion volumes to impart the Hoffmeister effect. Exceptionally, the most cost-effective ZnSO₄ yielded the highest ionic Seebeck coefficient among the hydrogels, with PAAm-1 ZnSO₄ achieving a remarkable value of -3.72 mV K^-1. To elucidate the underlying mechanism, we conducted an innovative analysis correlating the Seebeck coefficient with the zinc ion transfer number. Additionally, the hydrogel materials demonstrated outstanding mechanical properties, including high elongation at break (>1400% at its peak), exceptional resilience (virtually no hysteresis loops), and robust fatigue resistance (overlapping cyclic tensile curves). This work not only advances the understanding of ionic thermoelectric materials but also showcases the potential of hydrogels for practical waste heat recovery applications.

Understanding rock wettability is crucial across various fields including hydrology, subsurface fluid storage and extraction, and environmental sciences. In natural subsurface formations like carbonate and shale, mixed wettability is frequently observed, characterized by heterogeneous regions at the pore scale that exhibit both hydrophilic (water-wet) and hydrophobic (oil-wet) characteristics. Despite its common occurrence, the impact of mixed wettability on immiscible fluid displacement at the pore scale remains poorly understood, creating a gap in effective modeling and prediction of fluid behavior in porous media. The primary objective of this study was to investigate how mixed wettability affects pore-scale fluid displacement dynamics, utilizing microfluidic devices designed to replicate rock-like structures with varied wettability properties. Current techniques for achieving mixed wettability within microfluidic devices often struggle with spatial control and resolution, limiting their accuracy. To address this limitation, a novel approach was employed that combined photolithography and molecular vapor deposition of perfluorodecyltrichlorosilane to precisely and selectively modify wettability within specific pore regions, achieving a mixed wettability distribution correlated with pore size for the first time. The experimental setup included five identical micromodels representing distinct wetting conditions, which were initially saturated with air and subsequently flooded by water. By systematically varying the ratio of hydrophilic to hydrophobic areas, we covered a range from fully hydrophilic to fully hydrophobic and intermediate mixed wettability configurations. Comparative displacement experiments revealed that pore-level mixed wettability has a pronounced effect on fluid displacement behavior, influencing the injection time, spatial invasion patterns, and dynamic pressure profiles. Results indicated that both the injection time and dynamic pressure decreased with an increase in the hydrophilic area fraction. Each wettability configuration displayed unique sequences of pore-filling events, emphasizing the critical role of the wettability distribution in influencing displacement dynamics. While mixed wettability exhibited a clear monotonic effect on invasion time and dynamic pressure, saturation behavior was notably nonmonotonic. Interestingly, mixed wettability scenarios with relatively medium to high hydrophilic fractions demonstrated enhanced overall sweep efficiency compared to the hydrophobic case and reduced the bypassed gas phase relative to the hydrophilic case. However, inefficiently distributed mixed wet zones were found to reduce the sweep efficiency. These findings highlight the critical influence of mixed wettability in fluid displacement processes, with significant implications for applications in oil recovery, CO₂ sequestration, and other subsurface energy technologies.

The hard disk medium (HDM) with a carbon overcoat (COC) is a fundamental component of a hard disk drive. The conventional test for its corrosion durability, known as the "HOT/WET test," requires considerable time and effort and does not provide any local information about the corrosion. Here, we address this issue by employing open-loop electric potential microscopy (OL-EPM), a potential measurement technique based on atomic force microscopy (AFM), for corrosion inspection. To explore the applicability of OL-EPM, we observed the surface of the HDMs with different COC thicknesses in a dilute HNO₃ solution. Through time-dependent and high-resolution OL-EPM observations, we found that this technique can be used for detecting nanoscale COC defects. This is because the HDM surface under a COC defect is exposed to the solution and undergoes anodic dissolution, increasing the local potential around the defect. This is readily detected by OL-EPM even before corrosion product formation around the defects induces the topographic change. This work demonstrates that OL-EPM is useful not only for understanding the local corrosion mechanisms but also for detecting the COC defects in a much shorter time (∼3 h) than the HOT/WET test (3-4 days).