Small Methods最新文献

Based on its advantages of high specific capacity, excellent rate capability, and low cost, Nickel-rich layered oxide cathode materials LiNi_xCo_yMn_1-x-yO₂ (Ni-rich NCM, x ≥ 0.9) have become a key choice for the new energy vehicle industry. During electrochemical cycling, however, multiple phase transitions-particularly the detrimental H2-H3 transformation induces abrupt anisotropic lattice distortion along the c-axis. This leads to the formation of microcracks within Ni-rich NCM, which results in the gradual degradation of capacity retention and thermal stability. This study reports an ultra-high nickel cathode material with an in situ stable rock-salt layer constructed on the surface. The NiO rock-salt layer can serve as a covering layer for the material, reducing its direct contact with the electrolyte. Additionally, due to the dispersed primary particles of single-crystal LiNi_0.9Co_0.05Mn_0.05O₂ cathodes (NCM90-S), anisotropic stress change is avoided, and crack formation is effectively suppressed during cycling, demonstrating exceptional cycle performance. Consequently, compared to polycrystalline LiNi_0.9Co_0.05Mn_0.05O₂ cathodes (NCM90-P), NCM90-S achieves superior capacity retention after 300 cycles at 1C (80.2% vs. 60.3%).

Two-dimensional (2D) transition metal dichalcogenides exhibit strong excitonic responses, direct bandgaps, and remarkable nonlinear optical properties, making them highly attractive for integrated photonic, optoelectronic, and quantum applications. Here, we present a large-area freestanding membrane photonic platform that achieves exceptional enhancement of light-matter interactions in monolayer WSe₂ via quasi-bound states in the continuum (quasi-BICs). The freestanding architecture effectively suppresses radiative losses and supports high-Q optical resonances, leading to enhanced light-matter interactions. This results in significant photoluminescence emission and second-harmonic generation (SHG) enhancement factors of 1158 and 378, respectively, with spatial uniformity sustained across a 450 × 450 µm² area. This uniform SHG enhancement further enables polarization-resolved mapping of crystal orientation and grain boundaries, offering a practical method for large-area structural characterization of 2D materials. Moreover, femtosecond-pumped SHG spectra reveal multiple narrowband peaks originating from distinct quasi-BIC modes-providing direct spectral evidence of resonantly enhanced nonlinear coupling. The combined attributes of strong optical enhancement, spectral selectivity, and wafer-scale compatibility establish this platform as a scalable interface for 2D semiconductor integration in next-generation optoelectronic, nonlinear, and quantum photonic technologies.

Memristor-based olfactory systems have attracted significant interest. However, a multifunctional memristor array capable of sensing, memory, and computation has not been realized. This study develops a selector-less crossbar array (CBA) composed of Pt/HfO₂ nanorods/TiN memristors, termed "chemo-memristive" devices, that exhibits asymmetric current-voltage (I-V) characteristics under a hydrogen (H₂) atmosphere. H₂ exposure creates oxygen vacancies (V_O) in the nanogap, corresponding to the ruptured filament region. The V_O-H complexes form shallow traps that enable trap-assisted conduction under the TiN-injection polarity, thereby switching the I-V response from symmetric to a polarity-dependent, asymmetric one. This yields an H₂‑assisted intermediate‑resistance state and enables analog resistance tuning via NG widening. Hence, precise conductance modulation and cell-selective readout were achieved by exploiting the forward-reverse current asymmetry, as validated in selector-free operation of a 3 × 3 CBA. Modified National Institute of Standards and Technology digit pattern-recognition simulations demonstrate high inference accuracy (>94%) with highly linear and symmetrical conductance modulation, suitable for large-scale arrays. The adjustable I-V properties allow an electrically reconfigurable olfactory network that can process H₂ flow patterns using high-dimensional graph features. A single H₂‑assisted CBA integrates selective sensing, which reinforces intended paths, with analog in‑memory computation, enabling combined neuromorphic and electronic‑olfaction functionality.

Lithography serves as a foundational process in semiconductor fields, enabling high-resolution patterning and transfer. Among various pattern transfer methods, the lift-off process is widely used owing to its material versatility and etch-free advantages. However, conventional lift-off faces several limitations, including solvent-related environmental concerns, low yield, and poor pattern fidelity. To overcome these challenges, we introduce a solvent-free dry lift-off method based on polyvinylidene fluoride (PVDF), a functional polymer with a high thermal expansion coefficient. Thermal shrinkage of PVDF under controlled heating and cooling conditions mechanically interlocks with the resist, enabling spontaneous delamination of the resist structure without the need for solvents or mechanical forces. This method achieves 100% yield and rapid fabrication of high-resolution, high-density patterns at the wafer scale. The process is compatible with both photolithography and electron-beam lithography. We further demonstrate its application in multilayer film-based Fabry-Pérot cavity devices, achieving large-area, uniform structural color patterns. This work establishes a scalable, environmentally friendly spontaneous dry lift-off strategy for next-generation sustainable micro- and nanofabrication.

Proper physicochemical characterization of advanced materials and complex industrial composites remains a significant challenge, particularly for nanomaterials, whose nanoscale dimensions and mostly complex chemistry challenge the analysis. In this work, we employed a correlative analytical approach that integrates atomic force microscopy (AFM), scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), Auger electron spectroscopy (AES), and Raman spectroscopy. This combination enables detailed chemical and structural characterization with sub-micrometer spatial resolution. Three commercial graphene-based materials of varying complexity were selected and investigated to test the analytical performance of this approach. Furthermore, one of the commercial graphene oxide samples was chemically functionalized via amination and fluorination. This allowed us to assess how surface modifications influence both the material properties and the limits of the applied analytical techniques.

Controlled sulfur vacancies (S_v) engineering in monolayer molybdenum disulfide (ML-MoS₂) has emerged as a powerful strategy to enhance its surface-enhanced Raman scattering (SERS) performance. In this study, we investigate the effect of chemical (H₂O₂) etching time on S_v formation in ML-MoS₂ and its subsequent impact on SERS activity. An optimal etching time (∼3 min for 20% H₂O₂) yields a high density of S_v sites that act as active adsorption centers and localized donor states, resulting in an ∼80-fold increase in enhancement factor (EF) and a ∼100-fold improvement in the detection limit (2.35 × 10^-10 m) compared to pristine MoS₂ (1 × 10^-8 m), while performing SERS measurements. In addition, donor-like behavior of the S_v sites is confirmed by computational simulations. However, prolonged etching beyond the optimal S_v concentration results in oxygen substitution at S_v sites, significantly reducing the adsorption capacity and surface chemical activity of ML-MoS₂, ultimately impairing its SERS performance. This study highlights the critical role of the etching duration in modulating S_v-defects to tune the opto-chemical properties of ML-MoS₂, offering a promising strategy for the development of chemical mechanism-based SERS sensing platforms.

Triboelectrification has been known for millennia and remains of great practical importance, with applications spanning pharmaceuticals, electronics, industrial processes, and especially energy harvesting. Its inherent complexity, however, has long hindered a definitive understanding. In recent years, the advent of triboelectric nanogenerators (TENGs) has stimulated extensive experimental investigations and, in parallel, the development of promising first-principles-based theoretical models. Together, these advances have begun to clarify fundamental aspects of triboelectric charge transfer. This review traces the progression from early electron-transfer concepts to recent frameworks, including the backflow-stuck charges, thermoelectric, flexoelectric, and mechanochemical models. We discuss their evolution, the problems they address, the discoveries and insights they have enabled, as well as their limitations. At the beginning of the manuscript, special emphasis is given to the development of TENGs, which have both advanced practical applications and uncovered new triboelectric phenomena. Finally, we identify key open challenges and provide an outlook on future directions. The integration of complementary models through multiscale approaches, supported by systematic experimental validation, offers the most promising pathway toward a comprehensive understanding of this long-standing problem and the rational design of triboelectric materials and devices.

Herein, we report a novel erlotinib (EH) -loaded calcium carbonate (CaCO₃) tubular micromotor fabricated via an internal-filling strategy, achieving a high drug payload of 2.53 × 10^{- 1 2} mol per micromotor, which integrates three core functionalities in one system: targeted delivery of EH, pH-responsive release, and ultrasound-based tracking. The microtube structures (10 µm in diameter) are prepared by electrochemical deposition, followed by filling the EH@CaCO₃ microparticle into the interior of the tubular motor. Distinct from the surface coating approach for drug immobilization, this internal-filling strategy enables substantially greater payloads. The EH@CaCO₃ tubular micromotor shows favorable bubble and magnetic propulsion capabilities. Serving as a proof-of-concept for targeted anti-cancer drug delivery, these micromotors can transport drugs within microchips channel to the targeted position. Under acidic conditions, CaCO₃ undergoes decomposition to release the encapsulated drug. Concurrently, the Zn-based inner structure of the tubular micromotor reacts with hydrogen ions (H⁺), leading to micromotor degradation and thereby facilitating rapid drug release. The as-released drug shows cell killing ability toward non-small cell lung cancer cells A549. Meanwhile, as the micromotors move in an acidic environment, the in situ generated bubbles can act as "ultrasonic contrast agents", thereby enabling real-time tracking of the micromotors. For potential in vivo applications, this facilitates the tracking of such motors in scenarios where optical microscopy is ineffective. The blood compatibility, coagulation function, and preliminary in vivo immune response evaluation all indicate that the system had good biosafety. This study provides a new idea for the development of a next-generation micro drug delivery platform with high drug loading, intelligent delivery, and real-time visualization.

The high thermoelectric performance of Fe₂VAl stems from its sharply rising band edges on either side of the band gap, which is highly sensitive to composition. Addressing reproducibility and scale-up challenges, we have developed a strategy to enhance its p-type thermoelectric performance by defects and grain boundary engineering through regulating the V/Al ratio and In-doping in Fe₂V_0.85Ti_0.1Ta_0.05Al. p-type performance of Fe₂VAl has typically lagged behind n-type. In this work, a significant enhancement in power factor is realized near room temperature through a wetting effect. Additionally, a two-step metallization process is developed for both p- and n-type Fe₂VAl thermoelectric legs, allowing to achieve significantly low contact resistance and maximize power output. Ultimately, a high output power density of 624 mW/cm² with ΔT = 327 K is achieved for the All-Fe₂VAl two-pair module, 3.8 times the previous highest reported value. Despite its relatively high thermal conductivity, the impressive high power density makes it a possible choice for certain power generation and cooling applications, with benefits of material non-toxicity, inherent stability, and high mechanical strength. This study presents a novel approach to enhancing the thermoelectric performance of p-type Fe₂VAl through the wetting effect, achieving high output power density in abundant and relatively inexpensive All-Fe₂VAl-based devices.

Single-walled carbon nanotubes (SWCNTs) exhibit exceptional optical and electronic properties but require proper dispersion in a liquid for solution process and biological applications. Here, we present a semi-automated platform for consistent fabrication of ssDNA-wrapped SWCNT dispersions. Conventional manual preparation methods suffer from batch-to-batch variations due to imprecise SWCNT weighing and inconsistent sonication parameters. Our system integrates an XYZ-motorized stage with a programmable tip sonicator and the preparation of SWCNT mass source with high consistency, enabling unprecedented consistency and automated processing of multiple samples. This platform enables systematic investigation of fabrication parameters, including ssDNA:SWCNT mass ratio, sonication power, and duration. We evaluate the performance of these hybrids as serotonin nanosensors, analyzing their fluorescence response characteristics and sensitivity. Our approach significantly reduces human labor while providing precise control over critical parameters, yielding consistent, high-quality serotonin-responsive nanosensors. This research demonstrates the importance of automated fabrication processes for achieving reliable and scalable production of SWCNT-based nanomaterials with uniform sensing properties.