Small Methods最新文献

The direct synthesis of graphene on dielectric substrates has attracted growing interest due to its potential for scalable, transfer-free integration in electronic and photonic applications. However, graphene grown on dielectrics typically exhibits lower carrier mobility compared to copper-grown counterparts, limiting its performance. Here, we report the synthesis of large-area graphene on Al-rich reconstructed c-plane sapphire (0001) via chemical vapor deposition (CVD) and reveal that, over time and under ambient storage conditions, a spontaneous decoupling occurs at the graphene-sapphire interface. Raman spectroscopy reveals a reduction in both strain and doping in the aged samples, consistent with electrical transport measurements showing a twofold increase in carrier mobility. X-ray photoelectron spectroscopy (XPS) and cross-sectional transmission electron microscopy (cross-sectional TEM) identify the intercalation of oxygen-containing species at the interface as the mechanism responsible for the decoupling. These findings uncover a previously unrecognized pathway to enhance the electronic performance of directly grown graphene on sapphire, reinforcing the viability of this platform for future scalable graphene-based technologies.

Fusion of extracellular vesicles (EVs) with liposomes can be used to alter the properties of EVs to enhance their drug delivery capabilities. However, metrics for assessing fusion are not well established. Fusion efficiency, the most frequently provided metric, is often characterized in bulk, clouding distribution of fusion across heterogeneous EV populations, and lacking assessment of more precise physical effects of fusion. Here we applied orthogonal single-particle techniques including nanoparticle-tracking analysis (NTA), resistive-pulse sensing (RPS), nanoscale flow cytometry, interferometric fluorescence imaging, and laser trapping Raman spectroscopy (LTRS), each with different limitations, to examine the effects of fusion. All techniques reduced particle number, while single-particle fluorescence analyses revealed substantial differences in fused-particle yield. Nanoscale flow cytometry and interferometric fluorescence imaging consistently identified freeze-thaw and sonication as producing the highest numbers of fused vesicles, with freeze-thaw generating the lowest proportion of non-fused EVs and liposomes. Interferometric fluorescence imaging further showed that fused vesicles retained native EV membrane proteins, but that fusion also reduced the abundance of these proteins, indicating membrane perturbation. We introduce here a multi-metric framework to evaluate fusion efficiency, purity, and physical alterations to vesicles, as a basis for comparing techniques and to support future optimization of engineered EV formulations.

All-polymer solar cells (all-PSCs) suffer from significant challenges of large-scale aggregation and phase separation due to poor compatibility between donor and acceptor polymers. In this study, we introduce volatile solid additives to regulate intermolecular interactions and improve blending miscibility, thereby controlling aggregation and phase separation. Both computational and experimental results reveal that the key to this regulation lies in the strong electrostatic potential coupling between the solid additive and the polymer acceptor. This selective interaction modulates the aggregation behavior during film deposition and thermal annealing, enabling a gradual phase evolution. Further analysis indicates that the strong electrostatic coupling reduces aggregate size and promotes more ordered molecular packing, ultimately optimizing the film morphology. As a result, all-PSCs based on PM6/PY-IT incorporating the solid additive 2-BDBF exhibit a significantly improved power conversion efficiency of 18.62%, representing an increase compared to 14.93% ender the control conditions. This work demonstrates that solid additives with engineered electrostatic interactions offer an effective strategy to tune intermolecular forces, optimize morphology evolution, and boost device performance in all-PSCs.

Surfaces with a water contact angle greater than 150° are defined as superhydrophobic surfaces, exhibiting characteristics such as water repellency, self-cleaning ability, and extremely low friction with water droplets. Most superhydrophobic surfaces possess micro- or nanoscale hierarchical structures; however, the fabrication of superhydrophobic surfaces typically requires considerable time and cost. Herein, we report a facile method for fabricating hierarchical structures via condensation of water vapor to address these problems. The size of the hierarchical structures can be controlled by adjusting the condensation time. The hierarchical structures via water vapor condensation exhibit the features of superhydrophobic surfaces, as confirmed by measurements of contact angle, sliding angle, and droplet impact behavior. As a feasible application, a self-cleaning test is also carried out. The facile fabrication method in this study is expected to be easily applicable for hierarchical structure formation and further extended to large-area sample production.

Self-propelled micromotors hold great promise for improving the performance of electrochemical biosensors by overcoming mass transport limitations inherent to target recognition on electrode surfaces. However, the successful integration of micromotors in electrochemical biosensors for the analysis of crude biological samples has remained elusive. In this study, we introduce the Motolyzer, a micromotor-based assay that utilizes DNAzymes for the identification and detection of bacterial targets in crude biological samples. In this system, immobilized DNAzymes are propelled by magnetic-layered micromotors within biological samples. Upon encountering their specific targets, these DNAzymes release redox DNA barcodes, which are subsequently analyzed using electrochemical chips. The Motolyzer significantly enhances the target-to-blank ratio of the biosensor (4.5 times) and achieves a limit-of-detection of 2 × 10⁴ CFU mL^-1 for Legionella pneumophila, a slow-growing bacterium, within 1 h, thereby eliminating the need for bacterial culture. Notably, the Motolyzer exhibits high specificity against non-target bacterial strains as well as non-bacterial metabolites, establishing it as a reliable, rapid assay for the identification of specific bacteria in crude biological samples. The versatility of this approach opens promising avenues for the rapid detection of various pathogens and biomarkers in both clinical and environmental settings.

Vat photopolymerization is a high-resolution and high-throughput technology used in many biomedical applications. However, achieving geometric precision in printed devices with features spanning orders of magnitude in length scale is non-trivial. Here, a new characterization tool combining fast, high-resolution optical coherence tomography imaging with a high-powered digital light processing projector enables real time measurements of photopolymer curing. The direct, quantitative measurement of hydrogel working curves (the relationship between cure depth and light exposure) shows that the critical energy for gelation (E_c) exhibits extreme size dependence, demanding a rethinking of gray-scaling light intensity for achieving predictable voxel formation at high resolutions. This in situ method also enables measurement of size-dependent working curves and dead zone thicknesses using oxygen permeable window materials, which is impossible via ex situ methods. Generally, size sensitivity is amplified at low irradiance, high dye-loading, and in the presence of oxygen permeable windows. Despite the extreme size sensitivity, calibrating the light exposure to the size dependent E_c allows a 3x improvement in layer-growth uniformity compared to a naïve approach. Overall, these results highlight the challenges in high-resolution printing of hydrogels and provide a framework to measure and account for size dependence.

Stress distribution maps in polycrystalline materials are needed to reveal stress pathways caused by short-and long-range interactions of crystallites. Stress induced changes to wavenumbers in Raman spectroscopy is a well-known phenomenon that occurs when a crystalline material undergoes elastic strain. Using spatially resolved Raman spectroscopy, we have developed a technique to experimentally measure grain-scale residual stresses across a sample of polycrystal quartz Tiger's Eye. The results of this technique are validated using multiple criteria, including evaluation of the residual stress map itself and the accuracy of the measurements taken. The residual map of Tiger's Eye shows striking similarity to observed characteristics of other polycrystalline residual stress distributions, revealing heterogenous areas of high and low magnitude stresses. The stress magnitudes are consistent with residual stress magnitudes previously measured from polycrystalline quartz. Characterization of Tiger's Eye quartz also revealed the geometric nature of the iron oxide inclusions, not previously observed in Tiger's Eye quartz. With this technique, we present a residual stress map of Tiger's Eye quartz that shows with accuracy a heterogeneous stress state with inter- and intra-granular detail.

Achieving high efficiency perovskite light-emitting diodes (PeLEDs) requires transparent electrodes that combine low sheet resistance, high optical transmittance, and atomically smooth morphology. Conventional crystalline indium tin oxide (ITO) electrodes, however, necessitate high-temperature deposition above 300°C or post-annealing, resulting in grain boundaries and rough surfaces that are incompatible with flexible substrates and low-temperature device architecture. Here, we report room-temperature processed, grain boundary-free Sn excess doped indium tin oxide (SE-ITO) electrodes fabricated via RF-RF co-sputtering of In₂O₃ and SnO₂. Through the heavy incorporation Sn⁴⁺ dopants (19 wt.%) and optimized oxygen-vacancy engineering, the amorphous SE-ITO achieves an exceptional combination of low sheet resistance (10 Ω sq^-1) and high visible transmittance (85%), comparable to thermally annealed crystalline ITO. When implemented as the transparent anodes in green PeLEDs, the amorphous SE-ITO films enable a peak external quantum efficiency of 17.5% and a maximum luminance of 1860 cd m^-2, outperforming devices using commercial crystalline ITO (16.3%, 1690 cd m^-2). These results establish fully amorphous, room-temperature SE-ITO electrodes as a viable alternative to crystalline counterparts, offering a new pathway toward flexible, high-efficiency, and thermally compatible PeLED technologies.

Synthesis of nanomaterials via plasma plume ablation offers a rapid and surfactant-free route for nanoparticles production. However, controlling nucleation under highly non-equilibrium conditions remains a major challenge, often leading to low yield and poor size uniformity. Here we demonstrate that introducing heterogeneous metal ions into the ablation medium provides an effective strategy to regulate plasma plume. Using pulsed laser ablation in liquids as a model system, we show that dissolved metal ions undergo heterogeneous nucleation, thereby simultaneously suppressing plume redeposition. Using silver ions （Ag⁺） as a representative ion, we identify an optimal concentration window (∼1 mm) that maximized nanoparticle yield while producing uniformly small IrAg nanoparticles. A systematic ion library further reveals that the promotion efficiency across different ions correlates strongly with the standard reduction potential (E°), establishing a quantitative link between ion reducibility and plume behavior. These results demonstrate that thermodynamic driving forces bias the relative rates of reduction and nucleation, thereby selecting the dominant condensation pathway under non-equilibrium conditions. This ion-regulated strategy extends the classical LaMer framework into plasma plume synthesis and provides predictive guidelines for scalable, size-controlled nanomaterial production.