Small Methods最新文献

Grain boundaries (GBs) and surface defects within perovskite films are inherent challenges that affect the photovoltaic performance of perovskite solar cells  (PSCs. In this work, Nylon 11 (N11) is utilized, a long-chain polymer, for post-treating the GBs and surface defects within FAPbI₃ films. The multifunctional groups of N11 exhibit unique passivation abilities, enabling self-regulation and selective correction of reverse-charged defects. Post-treating with N11 results in high-quality FAPbI₃ films characterized by tight GBs and low surface defect density. Despite fabrication under full open-air conditions, the N11 post-treatment significantly enhances the power conversion efficiency (PCE) value of FAPbI₃ PSCs, increasing it from the reference value of 21.89% to 23.54%. Importantly, the long alkyl chain present in N11 significantly enhances the humidity stability of the PSCs. Unencapsulated PSCs treated with N11 maintain 89% of their initial PCE after exposure to air with 30% relative humidity (RH) for 1000 h, demonstrating resilience to elevated humidity levels. This work highlights the substantial improvement in the photovoltaic performance of PSCs achieved through the post-treatment with N11.

Nucleic acid-based molecular recognition plays crucial roles in various fields like biosensing and disease diagnostics. To achieve optimal detection and analysis, it is essential to regulate the response performance of nucleic acid probes or switches to match specific application requirements by regulating thermodynamics and kinetics properties. However, the impacts of thermodynamics and kinetics theories on recognition performance are sometimes obscure and the relative conclusions are not intuitive. To promote the thorough understanding and rational utilization of thermodynamics and kinetics theories, this review focuses on the landmarks and recent advances of nucleic acid thermodynamics and kinetics and summarizes the nucleic acid thermodynamics and kinetics-based strategies for regulation of nucleic acid-based molecular recognition. This work hopes such a review can provide reference and guidance for the development and optimization of nucleic acid probes and switches in the future, as well as for advancements in other nucleic acid-related fields.

In order to improve the solubility of metallated monomers and product crystallinity, metal-covalent organic frameworks (MCOFs) are commonly prepared via high-temperature sol-vothermal synthesis. However, it hampers the direct extraction of crystallization evolution information. Exploring facile room-temperature strategies for both synthesizing MCOFs and exploiting the crystallinity mechanism is extremely desired. Herein, by a novel single-phase synthetic strategy, three MCOFs with different microstructure is rapidly prepared based on the Schiff base reaction between planarity-tunable C_3v monomers and metallated monomers at room temperature. Based on detailed time-dependent experiments and theoretical calculations, it is found that there is a planarity-tuned and competitive growth relationship between disordered structures and crystal nucleus for the first time. The high planarity of monomers boosts the formation of crystal nucleus and rapid growth, suppressing the forming of amorphous structures. In addition, the microenvironment effect on selective photocatalytic coupling of benzylamine (BA) is investigated. The strong donor-acceptor (D-A) MCOF exhibits efficient photocatalytic activity with a high conversion rate of 99% and high selectivity of 99% in 5 h under the 520 nm light irradiation. This work opens a new pathway to scalable and efficient synthesis of highly crystalline MCOFs.

The popularity of portable and wearable flexible electronic devices, coupled with the rapid advancements in military field, requires electromagnetic interference (EMI) shielding materials with lightweight, thin, and flexible characteristics, which are incomparable for traditional EMI shielding materials. The film materials can fulfill the above requirements, making them among the most promising EMI shielding materials for next-generation electronic devices. Meticulously controlling structure of composite film materials while optimizing the electromagnetic parameters of the constructed components can effectively dissipate and transform electromagnetic wave energy. Herein, the review systematically outlines high-performance EMI shielding composite films through structural design strategies, including homogeneous structure, layered structure, and porous structure. The attenuation mechanism of EMI shielding materials and the evaluation (Schelkunoff theory and calculation theory) of EMI shielding performance are introduced in detail. Moreover, the effect of structure attributes and electromagnetic properties of composite films on the EMI shielding performance is analyzed, while summarizing design criteria and elucidating the relevant EMI shielding mechanism. Finally, the future challenges and potential application prospects of EMI shielding composite films are prospected. This review provides crucial guidance for the construction of advanced EMI shielding films tailored for highly customized and personalized electronic devices in the future.

Metabolic RNA labeling-based time-resolved single-cell RNA sequencing (scRNA-seq) has provided unprecedented tools to dissect the temporal dynamics and the complex gene regulatory networks of gene expression. However, this technology fails to reveal the spatial organization of cells in tissues, which also regulates the gene expression by intercellular communication. Herein, it is demonstrated that integrating time-resolved scRNA-seq with spatial transcriptomics is a new paradigm for spatiotemporal analysis. Metabolic RNA labeling-based time-resolved Well-TEMP-seq is first applied to profile the transcriptional dynamics of glioblastoma (GBM) cells and discover two potential pathways of EZH2-mediated mesenchymal transition in GBM. With spatial transcriptomics, it is further revealed that the crosstalk between CCL2⁺ malignant cells and IL10⁺ tumor-associated macrophages in the tumor microenvironment through an EZH2-FOSL2-CCL2 axis contributes to the mesenchymal transition in GBM. These discoveries show the power of integrative spatiotemporal scRNA-seq to elucidate the complex gene regulatory mechanism and advance the understanding of cellular processes in disease.

The results of a combined grazing incidence wide-angle X-ray scattering (GIWAXS) and 4D scanning transmission microscopy (4D-STEM) analysis of the effects of thermal processing on poly(3[2-(2-methoxyethoxy)ethoxy]-methylthiophene-2,5-diyl) are reported, a conjugated semiconducting polymer used as the active layer in organic electrochemical transistor devices. GIWAXS provides a measure of overall crystallinity in the film, while 4D-STEM produces real-space maps of the morphology and orientation of individual crystallites along with their spatial extent and distribution. The sensitivity of the 4D-STEM detector allows for collection of electron diffraction patterns at each position in an image scan while limiting the imparted electron dose to below the damage threshold. The effects of heat treatment on the distribution and type of crystallites present in the films is determined.

Co-free Li-rich layered oxides (CFLLOs) with anionic redox activity are among the most promising cathode materials for high-energy-density and low-cost lithium-ion batteries (LIBs). However, irreversible oxygen release often causes severe structural deterioration, electrolyte decomposition, and the formation of unstable cathode-electrolyte interface (CEI) film with high impedance. Additionally, the elimination of cobalt elements further deteriorates the reaction kinetics, leading to reduced capacity and poor rate performance. Here, a multifunctional strategy is proposed, incorporating Li₂MnO₃ phase content regulation, micro-nano structure design, and heteroatom substitution. The increased content of Li₂MnO₃ phase enhances the capacity through oxygen redox. The smaller nanoscale primary particles induce greater tensile strain and introduce more grain boundaries, thereby improving the reaction kinetics and reactivity, while the larger micron-sized secondary particles help to reduce interfacial side reactions. Furthermore, Na⁺ doping modulates the local coordination environment of oxygen, stabilizing both the anion framework and the crystal structure. As a result, the designed cathode exhibits enhanced rate performance, delivering a capacity of 158 mAh g⁻¹ at 5.0 C and improved cyclic stability, with a high capacity retention of 99% after 400 cycles at 1.0 C. This multifunctional strategy holds great promise for advancing the practical application of CFLLOs in next-generation LIBs.

MXenes are prototypes of surface tunable 2D materials with vast potential for properties tuning. Accurately characterizing their surface functionalization and its role in electronic structure is crucial, X-ray photoelectron spectroscopy (XPS) being among the go-to methods to do so. Despite extensive use, XPS analysis remains however intricate. Focusing on the benchmark MXene Ti₃C₂T_z, Density Functional Theory (DFT) calculations of core-level binding energy shifts (BE.s.) are combined with experiments in order to provide a quantitative interpretation of XPS spectra. This approach demonstrates that BE.s. are driven by the complex interplay between chemical, structural, and subtle electronic structure effects preventing analysis from intuitive arguments or comparison with reference materials. In particular, it is shown that O terminations induce the largest BE.s. at Ti 2p levels despite lower electronegativity than F. Additionally, F 1s levels show weak sensitivity to the F local environment, explaining the single contribution in the spectrum, whereas O 1s states are significantly affected by the local surface chemistry. Finally, clear indicators of surface group vacancies are given at Ti 2p and O 1s levels. These results demonstrate the combination of calculations with experiments as a method of the highest value for MXenes XPS spectra analysis, providing guidelines for otherwise complex interpretations.

Graphene (Gr) and carbon nanotubes (CNTs), the two intriguing carbon nanomaterials, have presented great potential in serving as high-performance electrocatalysts in lithium-sulfur (Li-S) chemistry. The concurrent management of both materials would achieve a promoted synergistic effect. Nevertheless, there still remains a lack of an effective material synthesis route. Herein, a single-step plasma-enhanced chemical vapor deposition (PECVD) strategy is devised to prepare Gr@CNTs heterostructures with strong bonded connections. In the PECVD system, the damaged sidewalls generated in CNT tubes can serve as appropriate nucleation sites for further Gr growth. The formation mechanisms are thoroughly explored in aspects of both experimental characterizations and theoretical calculations. To confirm the validity of this approach, thus-constructed Gr@CNTs architectures are employed as the sulfur host, enabling boosted redox kinetics of polysulfides. This project provides fundamental insight into the mechanism exploration for single-step PECVD growth of Gr@CNTs heterostructure, hence promoting the practical application prospect of carbon nanomaterials toward Li-S systems.