Nanoscale最新文献

Correction and removal of expression of concern for 'A hysteresis-free perovskite transistor with exceptional stability through molecular cross-linking and amine-based surface passivation' by Hyeong Pil Kim et al., Nanoscale, 2020, 12, 7641-7650, https://doi.org/10.1039/C9NR10745B.

Engineering the surface chemistry of nanomaterials enables diverse applications but requires a clear understanding of how functional groups interact with nanomaterials. Here, a systematic study on the ligand-matrix chemistry of naturally occurring clay-based nanomaterials is conducted to enhance the recovery of rare-earth elements (REE) over common competing salt ions. Our results reveal a clear correlation among functional groups, surface chemistry, and equilibrium adsorption capacity, where transitioning from electron-withdrawing to electron-donating groups resulted in an enhancement of equilibrium adsorption capacity (more than 9 times). The engineered particles exhibit a strong affinity for REE over competing ions found in brine and wastewater (e.g., Na⁺, Mg²⁺, and Ca²⁺), facilitating highly selective REE recovery from complex environments containing trace-level REE (exceeding 85% recovery in oilfield produced water). Furthermore, the functionalized clay nanoparticles are formulated into 3D-printable inks for fabricating porosity-controlled, customizable adsorbent prototypes, where the controlled macro-channel architecture enables improved adsorption kinetics (almost doubling the efficiency over a 24 h period) compared to chunk adsorbents of the same chemical composition without requiring external stirring, highlighting the potential for sustainable REE extraction.

Group II-VI semiconductor nanoplatelets (NPLs) have unique quantum confinement effects and large specific surface areas, offering distinct advantages in advanced optoelectronic devices, catalysis, and biomedical sensing. Carboxylate ligands are widely used in NPL synthesis; however, their roles in the synthesis process remain insufficiently understood. Herein, we systematically investigated the formation process of CdSe NPLs via a one-pot method using carboxylate ligands with different chain lengths and proportions. We found that ligand chain length can significantly influence the NPL formation. The ratio of short- to long-chain ligands governs the nucleation, growth pathway and final NPL morphology. For a low proportion of short-chain ligands, elongated NPLs formed during nucleation and subsequently underwent lateral expansion, yielding flat NPLs with high aspect ratios. In contrast, a high proportion of short-chain ligands resulted in the formation of dot-shaped nanocrystals during nucleation, which subsequently dissolved, accompanied by the gradual formation of NPLs with low aspect ratios and a curved morphology. We propose that these observations are associated with competitive interactions between short- and long-chain ligands at the nanocrystal surfaces. Short-chain ligands, due to weaker hydrocarbon chain interactions, promote lateral growth, whereas long-chain ligands preferentially inhibit lateral expansion. This study provides new insights into the formation mechanism of CdSe NPLs and facilitates morphology control and the practical application of related nanomaterials.

The thermal shrinkage and material deterioration of commercial polyolefin separators at high temperatures remain substantial barriers to safe lithium metal battery operation. In this work, bacterial cellulose (BC) nanofibers were employed as a matrix, with poly(p-phenylene benzobisoxazole) (PBO) nanofibers (PNFs) prepared via a reported protonation strategy. BC/PNF (BP) nanocomposite separators were fabricated via vacuum filtration. By incorporating 10 wt% PNFs, the BP10 separator retained an intact nanofibrous network and full dimensional stability after thermal treatment at 300 °C for 0.5 h, outperforming commercial PP in structural integrity. BP10 exhibited an ionic conductivity of 0.68 mS·cm^-1 and a lithium-ion transference number of 0.37, both exceeding those of PP. The Li/LiFePO₄ cells assembled with BP10 achieved 122.6 mAh·g^-1 after 200 cycles at 1C, and Li/Li symmetric cells sustained stable cycling for over 1000 h at 1.0 mA cm^-2; elevated-temperature cycling at 55 °C likewise outperformed PP. TG-FTIR analysis showed that PNFs shifted the thermal decomposition pathways of the nanocomposite separator, suppressing small-molecule volatile release such as CO and reducing total volatile products by ∼50%. The findings demonstrated a simple, fast and effective strategy for constructing nanocomposite separators from renewable BC and thermally robust PNFs for high-performance lithium metal battery separators with enhanced ionic transport and thermal stability.

Copper tungstate (CuWO₄) is a ternary metal oxide that has attracted sustained interest as a photoanode material for photoelectrochemical (PEC) water oxidation due to its visible light absorption, favorable band alignment, high theoretical photocurrent density and intrinsic chemical stability in oxidative environments. Despite these advantages, its performance remains limited by poor charge transport, short carrier diffusion lengths and pronounced recombination, making its PEC ability highly sensitive to synthesis-dependent characteristics established during fabrication. In this review, we revisit the evolution of CuWO₄ photoanodes, beginning with earlier studies that established its fundamental activity and examine how subsequent work has clarified the interplay between electronic structure, bulk properties and interfacial processes. Particular attention is given to the role of Cu oxidation states, defect chemistry and emerging insights into surface energetics and water adsorption, which collectively influence charge transfer kinetics at the semiconductor electrolyte interface. We provide a critical assessment of fabrication strategies, including solid-state, vapor phase and solution-based methods with emphasis on how precursor chemistry, stoichiometry and processing conditions govern phase formation, crystallinity and microstructural evolution. The influence of annealing temperature and atmosphere is discussed in relation to phase purity, defect populations and morphological stability, alongside challenges with controlling multiphase formation and compositional gradients. Strategies to improve performance, such as doping, morphology engineering, heterostructure design, and cocatalyst integration, are evaluated in the context of their impact on overall PEC performance and impact on bulk and electronic properties of the material. Through this analysis, key limitations and opportunities are identified, underscoring the need for more studies to advance CuWO₄ toward efficient and scalable PEC systems.

Metabolomics provides functional molecular readouts of disease phenotypes, therapeutic responses, and tissue microenvironments, but its extension to low-volume, single-cell, and spatially resolved samples remains analytically challenging. Laser desorption/ionization mass spectrometry (LDI-MS) offers a rapid, direct, and high-throughput route for small-molecule analysis. However, its performance in biomedical metabolomics is largely governed by the matrix-analyte interface. Nanomaterials have emerged as attractive LDI-MS matrices because of their low background in the low-mass region, large surface area, tunable photothermal and electronic properties, and designable surface chemistry. In this review, we summarize recent advances in nanomatrix-assisted LDI-MS for biomedical metabolomics, emphasizing design principles. We discuss three key design dimensions of nanomatrix and interface engineering: structural engineering for energy absorption and desorption efficiency, surface functionalization for metabolite enrichment and low-interference ionization, and interface engineering for reproducibility, throughput, and low-volume sample compatibility. Representative biomedical applications are highlighted, including biofluid metabolic fingerprinting, extracellular vesicle and single-cell metabolomics, and spatial metabolic imaging. Finally, we discuss current challenges in matrix reproducibility, metabolite coverage, workflow standardization, and clinical validation, and outline future opportunities for integrated nanomatrix platforms in multiscale biomedical metabolomics.

The discovery of altermagnetism, a novel magnetic order characterized by real-space antiferromagnetic alignment and reciprocal-space anisotropic spin polarization, has opened new avenues in spintronics and topological quantum materials. In this paper, we employ first-principles calculations to investigate the electronic structure, magnetic properties, and topological behavior of monolayer Fe₂I₂. We predict that this material hosts a stable d-wave altermagnetic ground state with an out-of-plane magnetic orientation. Our analysis reveals the presence of Weyl points with opposite Chern numbers near the Fermi level, establishing monolayer Fe₂I₂ as a bipolarized Weyl semimetal. Upon incorporating spin-orbit coupling (SOC), the crystal symmetry is reduced, leading to the opening of a finite bandgap (∼58.9 meV) at the Weyl points and inducing a quantum crystal valley Hall effect. Furthermore, we demonstrate that uniaxial strain along the a-axis serves as an effective knob for tuning the topological states: tensile strain induces a migration of Weyl points from the Γ-X to the X-M direction, while compressive strain significantly modulates the valley bandgap. With a predicted high Nel temperature of 630 K, monolayer Fe₂I₂ emerges as a promising candidate for ultrafast, low-power topological spintronic devices.

Substitutional doping provides an effective route for tailoring the optical and electronic properties of two-dimensional transition metal dichalcogenides. Here, we investigate the influence of Cr-induced defect states on the ultrafast carrier dynamics of monolayer MoS₂ (MS) using femtosecond transient absorption (TA) spectroscopy. Cr incorporation introduces distinct defect-related excitonic resonances that strongly modify the relaxation pathways of photoexcited carriers. Our measurements reveal enhanced bandgap renormalization and a progressive transfer of spectral population from the A exciton into Cr-induced defect states, indicating efficient carrier localization. At elevated excitation densities, a new defect-related transition emerges which exhibits distinct spectral evolution, relaxation dynamics, and superlinear population growth, consistent with charged defect-bound excitonic states. Interestingly, carrier trapping into Cr-induced states suppresses density-dependent exciton-exciton annihilation and prolongs excitonic lifetimes. Furthermore, the defect states exhibit exceptionally large saturation fluences (up to ∼640 µJ cm^-2), enabling substantially enhanced carrier-storage capacity. These findings establish dopant-induced defect engineering as a powerful approach for tuning ultrafast carrier relaxation and nonlinear optical response in monolayer MS, paving the way for advanced nonlinear photonic and optoelectronic devices.