Small Methods最新文献

Post-treatment has been regarded as an important strategy in thin-film fabrication, which surmounts the limitations in directly deposited films through manipulating the chemical, electrical, morphological, and defect properties. In terms of the emerging photovoltaic material antimony selenosulfide (Sb₂(S,Se)₃), conventional hydrothermal synthesis of Sb₂(S,Se)₃ thin film has achieved great improvement toward 10% efficiency bottleneck in solar cell applications. However, this fabrication method fails to achieve desirable carrier transport and defective properties. In this study, we develop an InCl₃-based post-treatment method to enhance the carrier transport and passivate the deep-level defects, including S and Se vacancies and anti-site defects (Sb_S(e)3). We find that the indium ions generated by post-treatment preferentially diffuse into the interstitial sites of (Sb₄S(e)₆)_n ribbons, leading to the formation of In-S(e) chemical bonds. These atomic interactions facilitate efficient carrier transport across the entire film. Furthermore, the synergistic effects of energy level alignment optimization, deep-level defect passivation, and interfacial trap inhibition effectively suppress non-radiative carrier recombination and improve photovoltaic performance. Consequently, this post-treatment enables the Sb₂(S,Se)₃ solar cell to achieve a remarkable power conversion efficiency of 10.55%. This study provides a novel post-treatment method for defect passivation, electronic structure regulation, and carrier transport management for high-performance antimony selenosulfide solar cells.

Femtosecond laser fabrication enables the creation of a wide range of devices, but its scalability and yield can be limited by the lack of real-time, in situ monitoring tools. In particular, there is a strong need for metrics that directly correlate with device performance. Raman microspectroscopy provides a non-destructive route for in situ characterization. Here, we demonstrate its potential to assess the electrical performance of laser-written graphitic electrodes in diamond. By combining hyperspectral mapping with electrical testing, we show that depletion of the 1332  ${\mathrm{cm}}^{-1}$ sp3 Raman line serves as a monotonic and robust predictor of resistance, offering clear advantages over commonly used spectral features. We further introduce hyperspectral unmixing as a label-free approach to identify relevant spectral signatures in fabrication processes where Raman markers are less defined. Importantly, the methodology we present is not restricted to diamond but can be adapted to other host materials and functionalities, offering a practical path toward specification-driven fs-laser microfabrication.

Fabrication of two-dimensional (2D) transition-metal oxides has gained considerable attention due to their unique crystal structures and physical properties distinct from their bulk counterparts. Intercalation of foreign elements into the graphene/SiC(0001) interface is a possible approach for achieving this, as it enables the confinement and arrangement of atoms within the 2D interface. However, while various 2D metals and their compounds have been synthesized at the graphene/SiC interface, the fabrication of 2D transition-metal compounds remains challenging. This difficulty arises from the high reactivity of transition metals such as Fe, Co, and Ni, which readily form carbides and silicides with the host material. In this work, the fabrication of a 2D iron oxide at the graphene/SiC interface is demonstrated through the simultaneous intercalation of Fe and O. Direct observation using atomic-resolution electron microscopy revealed that the crystalline 2D iron oxide is encapsulated by graphene and forms a sharp interface with the SiC substrate. Structural analysis and Mössbauer spectroscopy suggest that the 2D iron oxide exhibits a wüstite-like structure. These findings provide another strategy for synthesizing 2D transition-metal oxides, opening new avenues for the advancement of 2D magnetic materials.

A deep understanding of the catalytic interfacial processes in nanoscale systems is essential for the rational design of nanocatalysts. Specifically, for the complex photocatalysis on hydrogen peroxide (H₂O₂) production, multi-key-factors govern the catalytic interface. This study adopts silver-doped gold nanoclusters (AuAgNCs) to illustrate the influence of trace doping on key interfacial processes at the catalytic interface by spectroscopic characterization methods, including femtosecond transient absorption spectroscopy (fs-TAS), transient photovoltage (TPV), transient potential scanning (TPS), and transient photo-induced current (TPC). The research demonstrates that: 1) Ag incorporation not only enhances oxygen adsorption but also promotes its self-activation by oxygen; 2) The band structure of AuNCs and AuAgNCs exhibits no significant variation; 3) Charge carrier separation is facilitated while recombination is suppressed on AuAgNCs; 4) The oxygen reduction reaction catalytic pathway remains unchanged. Furthermore, the calculations of the Butler-Volmer equation demonstrate the reaction rates on the AuAgNCs are twice as much as those on AuNCs, in accordance with the activity improvement results. This work, based on operando analysis on the photocatalytic interface of the Au-Ag alloy nanocluster photocatalyst, shows detailed and distinct effects of Ag doping on oxygen adsorption/activation, charge carrier kinetics, and interfacial distribution.

Nickel-iron oxides have emerged as promising candidates to replace precious-metal-based catalysts for the oxygen evolution reaction (OER) owing to their abundance in the Earth's crust and, hence, low cost. However, their inherently poor electrical conductivity and inefficient utilization of active sites severely hinder their large-scale industrial deployment. Herein, we report a novel strategy for the construction of a self-supporting heterostructured electrode (FeOOH/NiFeO_x/NFF, where NFF = nickel-iron foam) via a combination of laser ablation and chemical corrosion. The resulting material has a distinctive heterogeneous structure and superhydrophilic and aerophobic surface properties that collectively promote electrolyte infiltration, gas release, and charge transfer. As a result, the FeOOH/NiFeO_x/NFF electrode achieves an ultralow overpotential of 208 mV at 10 mA cm^-2, along with excellent long-term durability. Mechanistic studies, including in situ spectroscopy and chemical probing, revealed that the exceptional OER performance is governed by a lattice oxidation mechanism. This work provides a viable and scalable pathway for the rational design of high-performance and economically feasible Ni-Fe-based electrocatalysts for industrial alkaline water splitting.

Electron transport layers (ETLs) with efficient electron extraction are essential for high-performance organic solar cells (OSCs). Sol-gel-derived zinc oxide (ZnO) is widely used as an ETL because of its high electron mobility and suitable work function; however, intrinsic defects in ZnO often limit the power conversion efficiency (PCE) of the device. To overcome this limitation, inverted OSCs employing ZnO doped with small molecule electrolytes (SMEs) as the ETL are developed. Rylene diimide-based SMEs containing tosylate anions, PDIN-OTs and NDIN-OTs, are synthesized and incorporated into ZnO for non-fullerene OSCs. The resulting ZnO-SME hybrid films significantly enhance device performance, yielding a PCE of up to 18.3%. Devices modified with PDIN-OTs exhibit higher short-circuit current density (J_sc), while those using NDIN-OTs show improved fill factor (FF). These enhancements arise from the effective passivation of ZnO trap states through interactions between tosylate anions and Zn ions in the ZnO lattice, consistent with a trap-filling mechanism. This interaction facilitates electron transport, suppresses charge recombination, and increases ZnO conductivity. In addition, reduced work function, Urbach energy, and trap density further promote efficient charge transport and collection. Overall, this study demonstrates that organic SMEs are effective ZnO modifiers and offer a promising strategy for improving OSC performance.

We report in this work highly efficient, temporally stable, and multicolor chemiluminescence of CdSe/CdS/ZnS quantum dots (QDs) boosted by radicals that are in situ electrogenerated near the electrode surface. Typically, electrochemical oxidation of tri-n-propylamine (TPrA), a tertiary amine, generates radical cation (TPrA^•+) and radical (TPrA^•). Then, TPrA^• and TPrA^•+ sequentially inject an electron and a hole to the valence and conduction bands of a QD to populate the excited state (QD*). In this pathway, a negatively charged QD (QD^-) is formed as the key intermediate, instead of fragile positively charged QD⁺, thus producing highly stable and efficient luminescence. Moreover, this pathway is also identical to the so-called low-oxidation-potential electrochemiluminescence route of the gold standard luminophore, tris(2,2'-bipyridyl)ruthenium (Ru(bpy)₃ ²⁺), and therefore fully fit for microbead-based bioassays. Considering their high emission efficiency (∼5 times higher than Ru(bpy)₃ ²⁺ under same condition), narrow emission bands and tunable wavelengths, these QDs hold great promise as luminophores in ultrasensitive and multiplexed microbead-based bioassays.

Data-driven flexible motion sensors have drawn more attention recently. Compared with the current mainstream motion capture technologies, like the depth-of-field camera with the environmental limitations, silicon-based inertial devices with a mismatch in mechanical properties between their rigid morphology and the soft biological tissues in a microenvironment, etc., wearable motion sensing technology presents obvious advantages. Here, we demonstrated theoretically and experimentally a conductive/dielectric heterogeneous-interface (CDHI) regulated motion sensor inspired by biological sensory systems. This kind of device can recognize both the motion directions and parameters of external objects with the corresponding potential signals, and the function can be further extended to 3D space through a programmed interface pattern and machine learning assistance. Results show that this potential amplitude can be up to ∼ 102 ± 5 mV, motion height up to 30 cm, and frequency as low as 0.2 Hz, motion space of 0°∼360° in horizontal direction and up-down in vertical direction, respectively. The practical feasibility was further explored for human finger interactive electronics successfully, including virtual interactive control, the Sokoban game, and human-hand/manipulator follow-up control, respectively. The proposed wearable 3D tactile communicator provides a new sensing experience that the present array sensors via a touch mode cannot offer.

Strain engineering offers a powerful route to modulate the electronic structure and light-matter interactions in 2D semiconductors. However, existing approaches largely rely on flexible substrates or mechanically complex micro-electromechanical platforms, which limit scalability, reconfigurability, and on-chip integration. Here we introduce an in-plane isolated gated architecture that establishes strong lateral electrostatic fields across a suspended monolayer MoS₂, delivering large-range, tunable, and reversible in-plane uniaxial strain without any other moving parts, by harnessing the electro-elastic coupling originating from in-plane symmetry breaking. In situ photoluminescence quantifies a monotonic bandgap tuning from 1.83 eV to 1.66 eV under electrostatic field modulation, corresponding to over 3% in-plane strain. With this platform, strain contrast between suspended and supported domains forms an addressable homojunction governed by field magnitude and channel orientation. This strain-defined junction exhibits rectification behavior and a tunable photoconductive cutoff wavelength spanning 640 to 785 nm. Leveraging these properties, a single standalone device achieves wavelength-division multiplexing signal separation and polarization-resolved photodetection without external optical components. These results suggest electrostatic-field-induced strain as a promising, scalable, and CMOS-compatible mechanism for operando localized strain engineering in 2D materials, provides a general route to unlock capabilities in spectral sensing, polarization-aware detection, and compact optical interconnects.