Small Methods最新文献

Organic solar cells (OSCs) face persistent challenges in maintaining both high efficiency and operational stability. Here, we report a rational design of D-A-type additives (UV326-DBOPA and UV327-DBOPA) that modulate morphology and transfer ultraviolet (UV) photons into utilizable photoexcitations through an energy-transfer process in the active layer, thereby simultaneously enhancing device performance and suppressing photodegradation. In PM6: Y6 and PM6: L8-BO systems, the power conversion efficiencies (PCE) reach 16.1% and 17.5%, respectively, accompanied by markedly prolonged lifetimes under continuous UV illumination. Further analysis reveals that the structure of D-A-type additives substantially influences molecular packing and the associated energy-transfer pathways. The less self-aggregated UV326-DBOPA provides a superior efficiency and stability by enabling optimized intermolecular packing and intrinsic energy transfer within the photoactive layer. This work provides an integrated strategy for regulating morphology and harnessing UV energy, offering guidance for future additive molecular design.

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.

Monitoring enzymatic reactions is crucial in enzymology, drug metabolism, and bioengineering. Supramolecular tandem enzyme assays (STA), based on indicator displacement assays, leverage the differential binding affinities of supramolecular hosts for enzymatic substrates and products. STA enables label-free, real-time, and rapid monitoring of enzymatic reactions, offering advantages such as simplicity, high sensitivity, and strong specificity. STA has been extensively employed to determine enzymatic kinetic parameters, screen inhibitors, diagnose biomarkers, and analyze enantiomeric excess. This review summarizes recent advancements in STA strategies across various enzyme types and provides current challenges and perspectives for future development.

Agglomeration and crystallization of atoms are the key processes in nucleation. For heterogeneous nucleation, investigating the influence of the substrate surface on agglomeration and crystallization, and then understanding the related mechanism at the atomic scale is crucial to material synthesis. Here, electron beam in transmission electron microscopy is utilized to decompose BiOCl material for generating dissociative Bi atoms. We observe the heterogeneous nucleation process of Bi nanocrystals at the surface of BiOCl from the side view with atomic spatial resolution and millisecond temporal resolution. The nucleation and crystallization of Bi nanocrystal is found to occur at the concave sites of the surface with angles ranging from 91° to 157° and form stable nucleus with sizes of 1 to 2 nanometers, while the pre-agglomerated Bi clusters dissociate again on the flat and convex surface. We demonstrate the collision between the Bi atoms and the concave structure helps Bi atoms release kinetic energy and form nucleus, and then the concave surface further stabilizes the nucleus and promotes crystallization.

Graphite carbon nitride has garnered significant research interest for photocatalytic pollutant degradation. However, the slow kinetics of the oxygen reduction reaction and the high recombination rate of photogenerated charges have hindered improvements in its performance. This paper synthesizes etched and crushed carbon nitride by introducing sulfonyl groups into it. Comprehensive experimental characterization and theoretical calculation show that the sulfonyl group optimizes the electronic structure of the catalyst and promotes the separation and migration of photogenerated charges. More importantly, the sulfonyl group is directly anchored at the hydrophobic interface, reducing the reaction energy barrier while promoting the photocatalytic self-Fenton efficiency. In addition, the modified catalyst achieved a maximum H₂O₂ yield of 1571.63 µmol g^-1 h^-1, with a high apparent quantum efficiency of 11.37% at 380nm and a solar-to-chemical energy conversion efficiency of 0.81%. Ciprofloxacin was degraded into non-toxic small molecules within 30 min, and the degradation kinetic efficiency was increased by 6.04 times. The photocatalytic performance has been significantly improved. This study provides a significant strategy for adjusting the structure of photocatalysts by introducing electron-withdrawing groups and directionally anchoring them at hydrophobic interface to enhance catalytic activity and also provides valuable insights for the design and development of highly efficient photocatalysts.

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.

The low-temperature synthesis of transition metal dichalcogenides (TMDCs) is essential for next-generation electronics, but this process remains a challenge. Generally, conventional methods require high temperatures, whereas existing low-temperature approaches depend on extrinsic modifications, such as plasma enhancement or specialized precursors, to enhance reactivity. In this study, a novel fundamental strategy was introduced on the basis of the intrinsic electronic engineering of transition metals (TMs). A bilayered junction protocol was proposed, where a buffer TM (b-TM) is placed beneath the target TM (t-TM) to facilitate TMDC synthesis. This junction precisely controls interfacial charge transfer, directly modulating the density of states (DOS) at the Fermi level of t-TM. The choice of b-TM enables the bidirectional tuning of DOS at the Fermi level of t-TM, thereby influencing chalcogen precursor adsorption and systematically reducing the required synthesis temperature. Using this approach, uniform, large-area TMDC nanosheets (exceeding 5.5 inches) were synthesized at remarkably low temperatures even on glass substrates, demonstrating the method's broad applicability. We have also demonstrated this capability with various TMDCs, including MoS₂, WS₂, MoSe₂, and WSe₂. Notably, all 25 fabricated memristor arrays on these films demonstrated exceptional performance, achieving remarkably uniform and ultra-low Set/Reset voltage profiles (±0.15 V). This work establishes a new paradigm for low-temperature synthesis of TMDCs, potentially applicable to the entire class of TMDCs, paving the way for advanced electronic applications on flexible and transparent substrates.

Conjugated microporous polymers (CMPs) have emerged as promising materials for energy storage devices, including lithium-ion batteries (LIBs), owing to their high surface area, chemical tunability, eco-friendliness, and fast redox kinetics. However, their practical applications are limited by poor conductivity, low active material utilization, lower redox potential and cycling degradation, which hampers their utilization for LIBs. Herein, we report the synthesis of dihydrophenazine based CMP (TPA-DPZ) with multi-redox centers and its composite with acid functionalized CNTs equal to only 5% of CNTs by total wt.% of monomers using in situ polymerization technique (TPA-DPZ@CNT 5%). The fabricated cathode with high active material loading of 80% with an average discharge potential of 3.39 V achieved a maximum specific capacity of 128 mAh g^-1. Remarkably, at a higher current density of 20 A g^-1, it retains a capacity of 68.34 mAh g^-1 with a discharge time of only 13 s. The electrode exhibits excellent long-term stability, retaining 89% of its initial capacity after 10 000 cycles. It possessed a high energy density of 445 Wh kg^-1 (at 0.1 A g^-1) combined with a high power density of 67 kW kg^-1 at 20 A g^-1. This work highlights the synergistic effect of multi-redox CMP and conductive CNTs in overcoming the limitations of organic electrodes.

Ectopic pregnancy (EP) is a leading cause of maternal morbidity and mortality in early pregnancy. Current diagnostic approaches, which rely on ultrasound scanning and blood measurements, are limited by low detection sensitivity. Herein, we propose a one-step system that uses EP-associated serum metabolic fingerprints (ESF) for efficient EP diagnosis and risk prediction. The system employs nanoparticle-assisted laser desorption/ionization mass spectrometry to rapidly record ESF. A machine learning-based diagnostic model was then used to analyze ESF from 722 participants, achieving an area under the curve (AUC) of 0.913. Simultaneously, potential metabolic biomarkers from ESF were annotated, enabling accurate diagnosis of EP across various clinical profiles (AUC 0.922). Moreover, a rupture risk prediction model was constructed, yielding an AUC of 0.885, significantly surpassing conventional clinical indicators (AUC 0.702, p < 0.05). Our work offers a rapid, effective tool for early EP diagnosis and risk stratification, marking a pivotal advancement toward precision diagnostics.

The diarylethenes (DAEs), renowned for their reversible photoisomerization, exhibit tunable bandgaps, conductivity, intramolecular or intermolecular radical and energy transfer processes. Leveraging these properties, we designed a DAE based polymer (DEP), and incorporated it as an additive in the photoactive layer of organic photodiodes (OPDs). Radical intermediates of DEP can enhance the photo response of OPDs. With 6 wt.% of DEP in PM6:PC₆₁BM, the suppressed dark current density (J_d) of 1.20 × 10^-9 A cm^-2, increased photocurrent density (J_p) of 9.66 × 10^-4 A cm^-2 and superior detectivity (D*) of 2.02 × 10¹³ Jones are measured at -2 V under 630 nm irradiation, which shows superior performances to its counterpart with J_d of 4.31 × 10^-7 A cm^-2, J_p of 7.02 × 10^-4 A cm^-2, and D* of 8.38 × 10¹¹ Jones without DEP. Mechanistic studies reveal that DEP suppresses dark current by modulating the bandgap and molecular interaction. Meanwhile, the distinct photo response of doped OPDs is attributed to enhanced exciton diffusion and to positive photoconductivity from photoinduced radical intermediates.