Materials Today Physics最新文献_第2页

Magnetic hardening via in-situ formed semi-coherent soft/hard magnetic phases in SmCo/FeCo nanocomposites SmCo/FeCo纳米复合材料原位形成半相干软磁/硬磁相的磁硬化

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2026-02-05 DOI: 10.1016/j.mtphys.2026.102045

Yingzhengsheng Huang , Wei Quan , Qiyao Geng , Longfei Ma , Qiang Zheng , Juan Du

Hard-soft magnetic nanocomposite magnets hold great promise for next-generation permanent magnets due to their ultrahigh theoretical maximum energy product ((BH)_max) and low-cost, while the low coercivity (H_c) of the currently fabricated SmCo/FeCo nanocomposites limits their performance. In this work, two types of microstructures with and without direct contacts between soft and hard magnetic phases in nanocomposites were designed and analyzed by micromagnetic simulations. The results showed that the directly contact nanocomposites exhibit a larger magnetic domain size and stronger interphase exchange coupling, facilitating magnetization of the hard magnetic phase and impeding reversal of the soft magnetic phase during magnetization and demagnetization processes. The simulation results were validated through the fabrication of SmCo/FeCo nanocomposites featuring an in-situ formed semi-coherent soft/hard magnetic phase. This nanocomposite was synthesized by crystallizing an as-milled amorphous Sm-Co-Fe precursor derived from a Sm-Co-Fe ingot. A reference magnet of without soft/hard magnetic phase contact, i.e. with amorphous-separated between two phases was fabricated by crystallizing amorphous-nanocrystalline precursor from co-milling Sm-Co alloy and Fe powders. Comparatively, the semi-coherent contact nanocomposite magnet showed a 28% increase in H_c and an 18% improvement in (BH)_max. Microstructural analysis revealed that the semi-coherent structure forms through synchronous crystallization driven by a compositional gradient. Micromagnetic simulations, Henkel curves, and in-situ domain observations confirmed that enhanced exchange coupling is the origin of H_c enhancement. This work provides a viable microstructural regulation strategy for developing high-performance nanocomposite magnets.

软硬磁性纳米复合磁体由于其超高的理论最大能积（BH）max)和低成本，在下一代永磁体中具有很大的前景，而目前制造的SmCo/FeCo纳米复合材料的低矫顽力（Hc）限制了它们的性能。本文采用微磁模拟的方法，设计和分析了纳米复合材料中软磁相与硬磁相直接接触和不直接接触的两种微观结构。结果表明，直接接触纳米复合材料具有更大的磁畴尺寸和更强的相交换耦合，在磁化和退磁过程中有利于硬磁相的磁化，阻碍软磁相的反转。通过制备原位形成半相干软硬磁相的SmCo/FeCo纳米复合材料，验证了仿真结果。该纳米复合材料是由Sm-Co-Fe铸锭衍生的非晶Sm-Co-Fe前驱体结晶而成的。采用Sm-Co合金和Fe粉末共磨非晶纳米晶前驱体，制备了无软硬磁相接触，即两相间无非晶分离的参考磁体。相比之下，半相干接触纳米复合磁体的Hc和BH分别提高了28%和18%。显微组织分析表明，在成分梯度的驱动下，晶化过程中形成了半相干结构。微磁模拟、汉高曲线和原位观测证实，增强的交换耦合是Hc增强的来源。本研究为开发高性能纳米复合磁体提供了一种可行的微结构调控策略。

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引用次数: 0

Semi-supervised spatiotemporal segmentation of in situ transmission electron microscopy for nanoparticle dynamics 透射电镜图像序列的半监督和时间感知分割

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2026-02-01 DOI: 10.1016/j.mtphys.2026.102033

Manpreet Kaur , Ali Ebadi , Xingying Zhang , Huanjing Liu , Cheng-Yu Chen , Eric A. Stach , Qian Liu

Understanding the real-time morphological evolution of nanoparticles under varying thermal and environmental conditions is crucial for revealing the mechanisms that govern their stability, growth, and functional performance in applications such as catalysis and nanomanufacturing. In-situ transmission electron microscopy provides direct, atomic-scale visualization of these dynamic processes through sequential imaging, capturing subtle transformations on a frame-by-frame basis. However, extracting reliable shape descriptors from such sequential image data remains challenging due to high noise, low contrast, inter-particle overlap, and the manual effort required for annotation. Existing segmentation methods often treat each frame independently, overlooking the temporal continuity inherent in in-situ imaging and failing to capture subtle but critical morphological transitions that underpin particle reshaping, coalescence, and structural evolution. To address these limitations, we present Swin U-Net Transformer with Temporal Convolutional Network for Segmentation (SwinTCN-Seg), a semi-supervised, spatiotemporally-aware framework that fuses transformer-based spatial encoding with temporal modeling to enable reliable analysis of morphological evolution in dynamic nanoparticle systems. Moreover, to reduce the need for dense manual labels, SwinTCN-Seg employs a pseudo-label propagation scheme that utilizes high-confidence predictions from labeled frames to guide learning on unlabeled ones, thereby uncovering transitional configurations. We validate SwinTCN-Seg on a large corpus of in-situ sequences of gold (Au) and platinum (Pt) nanoparticles imaged from 650 °C to 900 °C under vacuum and air environments. Despite being trained on only 5% of the labeled frames, the model achieves high segmentation accuracy, particularly in high-temperature regimes (

\geq

800 °C) where conventional methods struggle to detect complex phenomena such as faceting, sintering, and fragmentation. Code and models are available at https://github.com/kaur-manpreet325/TEM-Seg.

了解纳米颗粒在不同温度和环境条件下的实时形态演变对于揭示其稳定性、生长和功能性能的机制至关重要，这些机制在催化和纳米制造等应用中具有重要意义。原位透射电子显微镜通过顺序成像提供了这些动态过程的直接的、原子尺度的可视化，在逐帧的基础上捕捉细微的变化。然而，由于高噪声、低对比度、粒子间重叠以及注释需要人工操作，从此类连续图像数据中提取可靠的形状描述符仍然具有挑战性。现有的分割方法通常独立处理每一帧，忽略了原位成像固有的时间连续性，无法捕捉到支撑粒子重塑、聚并和结构演变的微妙但关键的形态转变。为了解决这些限制，我们提出了Swin U-Net Transformer with Temporal Convolutional Network for Segmentation (swintn - seg)，这是一种半监督的、时空感知的框架，融合了基于变压器的空间编码和时间建模，能够可靠地分析动态纳米颗粒系统的形态演变。此外，为了减少对密集手动标签的需求，SwinTCN-Seg采用了一种伪标签传播方案，该方案利用标记帧的高置信度预测来指导未标记帧的学习，从而揭示过渡配置。我们在650°C至900°C的真空和空气环境下的大量金（Au）和铂（Pt）纳米颗粒原位序列上验证了swintn - seg。尽管仅在5%的标记框架上进行了训练，但该模型实现了很高的分割精度，特别是在高温条件下（≥800°C），传统方法难以检测复杂现象，如切面、烧结和破碎。代码和模型可在https://github.com/kaur-manpreet325/TEM-Seg上获得。

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引用次数: 0

Advanced high-entropy nanoalloys toward renewable energy electrocatalysis 用于可再生能源电催化的先进高熵纳米合金

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2026-02-01 DOI: 10.1016/j.mtphys.2026.102035

Yajing Qi , Tianci Wei , Lin He , Xiaoran Bi , Xiaoyue An , Chunji Li , Weiwei Yang , Yongsheng Yu , Menggang Li

Alloying has long been recognized as one of the most promising strategies for designing high-performance metal-based electrocatalysts. However, the limited range of available elemental species in conventional alloys often restricts the continuous-tuning of the surface electronic structure of metal catalysts. High-entropy nanoalloys (HENAs), with their diverse compositional and structural characteristics, offer a pathway to overcome the limitations of traditional binary or ternary alloys, providing adsorption/desorption energies towards reaction intermediates closer to the optimum. Therefore, HENAs have emerged as promising candidates for electrocatalytic reactions integral to various renewable energy technologies, such as fuel cells, water electrolyzers, etc., and have witnessed remarkable progress in recent years. This review summarizes recent advances in HENA-based electrocatalysts for energy-related applications and highlights the crucial role of rational structural design in enhancing their performance. It begins with an introduction to the fundamental concepts, physicochemical properties, and structural characterizations of HENAs. Then, we categorize state-of-the-art HENA electrocatalysts based on their dimensionality, with particular emphasis on understanding their formation mechanisms at the nanoscale and atomic-scale. Furthermore, we discuss the rational underlying the structural regulation of electronic structures, electrocatalytic properties, and functional mechanisms of HENAs in several key electrocatalytic reactions. Finally, we outline the remaining challenges and future perspectives in this field, aiming to inspire the development of more advanced HENA-based catalysts to touch the ceiling of electrocatalytic activity and stability.

合金化一直被认为是设计高性能金属基电催化剂最有前途的策略之一。然而，传统合金中可用元素种类的有限限制了金属催化剂表面电子结构的连续调谐。高熵纳米合金（HENAs）以其不同的组成和结构特征，为克服传统二元或三元合金的局限性提供了一条途径，为反应中间体提供更接近最佳的吸附/解吸能。因此，HENAs已成为各种可再生能源技术（如燃料电池、水电解槽等）中不可或缺的电催化反应的有希望的候选者，并在近年来取得了显着进展。本文综述了基于hena的电催化剂在能源相关应用方面的最新进展，并强调了合理的结构设计在提高其性能方面的关键作用。首先介绍了HENAs的基本概念、物理化学性质和结构特征。然后，我们根据其尺寸对最先进的HENA电催化剂进行了分类，特别强调了在纳米尺度和原子尺度上对其形成机制的理解。此外，我们还讨论了HENAs在几个关键的电催化反应中的电子结构、电催化性能和功能机理的结构调控的合理性。最后，我们概述了该领域存在的挑战和未来的前景，旨在激发更先进的hena基催化剂的开发，以触及电催化活性和稳定性的天花板。

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引用次数: 0

Intrinsic photothermal performance and flexibility of polyurethane phase change materials via π-π conjugation for personal thermal management in outdoor cold environments 基于π-π共轭的聚氨酯相变材料在室外低温环境下的固有光热性能和柔性

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2026-02-01 DOI: 10.1016/j.mtphys.2026.102039

Wenxing Luo , Minming Zou , Jue Wang , Yan Ma , Xiaowu Hu , Wenjing Chen , Xiongxin Jiang , Qinglin Li

Phase change materials (PCMs) with photothermal properties can effectively convert solar energy into thermal energy and store it via phase change, subsequently provide heat for human body in cold environments. The introduction of photothermal fillers into polyurethane PCMs to develop photothermal polyurethane PCMs has been widely studied. However, the incompatibility between photothermal fillers and matrix leads to severe deterioration in the composite's flexibility. Therefore, achieving both the mechanical and photothermal properties of polyurethane PCM in wearable products is a pressing issue. In this work, a polyurethane PCM with intrinsic flexibility and photothermal properties was designed. It consists of small molecules filled with π-π conjugated structures and polyethylene glycol crosslinked through chemical interactions. By selecting diamine crosslinkers with varying conjugation strengths, the influence of π-π conjugation on flexibility and photothermal properties of polyurethane PCM was investigated. The results demonstrate that the stronger the π-π conjugation, the better the photothermal performance, with a photothermal conversion efficiency reaching up to 71.4%. Additionally, the strong intermolecular forces generated by π-π stacking also endow polyurethane PCM with high-temperature morphological stability, high tensile strength (22.4 MPa), and excellent toughness (351.1 MJ/m³). The intrinsic photothermal properties and good mechanical performance of polyurethane PCM make it suitable as a material for fabrics and coatings, ideal for wearable products in extreme cold environments, such as north pole and snowfields, where thermal energy is required.

具有光热特性的相变材料可以有效地将太阳能转化为热能并通过相变储存，从而在寒冷环境中为人体提供热量。将光热填料引入聚氨酯聚丙烯酸树脂中，开发光热聚氨酯聚丙烯酸树脂得到了广泛的研究。然而，光热填料与基体之间的不相容性导致复合材料的柔韧性严重恶化。因此，在可穿戴产品中实现聚氨酯PCM的机械性能和光热性能是一个紧迫的问题。本文设计了一种具有固有柔韧性和光热性能的聚氨基甲酸乙酯PCM材料。它由充满π-π共轭结构的小分子和聚乙二醇通过化学相互作用交联而成。通过选择不同共轭强度的二胺交联剂，研究了π-π共轭对聚氨酯PCM柔韧性和光热性能的影响。结果表明，π-π共轭越强，光热性能越好，光热转换效率可达71.4%。此外，π-π堆积产生的强大分子间作用力也使聚氨酯PCM具有高温形态稳定性、高抗拉强度（22.4 MPa）和优异的韧性（351.1 MJ/m3）。聚氨酯PCM固有的光热性能和良好的机械性能使其适合作为织物和涂料的材料，非常适合在极端寒冷的环境中使用可穿戴产品，如北极和雪原，这些环境需要热能。

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引用次数: 0

Wavelength-dependent photoresponse changes in graphene photodetectors induced by perovskite quantum dots 钙钛矿量子点诱导石墨烯光电探测器的波长相关光响应变化

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2026-02-01 DOI: 10.1016/j.mtphys.2026.102031

Young Jun Noh , Minjin Kim , Gi Hun Nam , Akash Gupta , Kootak Hong , Dongguen Shin , Doojin Lee , Yong Il Park , Sang Hyun Lee

Understanding the mechanisms underlying photocurrent generation in graphene-based photodetectors is essential for enhancing their spectral selectivity and response stability. Therefore, this study aims to systematically investigate and compare the photoresponse mechanisms of pristine monolayer graphene and CsPbBr₃ quantum dot (QD)-sensitized graphene heterostructures under 450 nm and 525 nm laser irradiation. Pristine graphene exhibits a wavelength-dependent photoresponse, with a pronounced negative photocurrent (NPC) under 450 nm irradiation due to photodesorption of p-type dopants and defect-assisted photoionization from the SiO₂ substrate. Under 525 nm irradiation, where photon energy is insufficient to activate surface and substrate mechanisms, graphene exhibited an unstable positive photocurrent (PPC) driven by weak photoconduction. In contrast, the CsPbBr₃/graphene heterostructure consistently exhibits strong and stable PPC at wavelengths. The integration of CsPbBr₃ QD enables efficient photocarrier generation and transfer to the graphene channel, overriding parasitic NPC pathways and stabilizing the overall photoresponse. Time-resolved measurements reveals significantly faster rise and fall times in the heterostructure, confirming a transition from slow surface-mediated processes to rapid photoconductive dynamics. This comparative study elucidates how intrinsic graphene properties, substrate interactions, and heterojunction effects collectively drive the photocurrent polarity and enhance performance in hybrid 2D/0D photodetectors.

了解石墨烯基光电探测器中光电流产生的机制对于提高其光谱选择性和响应稳定性至关重要。因此，本研究旨在系统研究和比较原始单层石墨烯和CsPbBr3量子点（QD）敏化石墨烯异质结构在450 nm和525 nm激光照射下的光响应机制。原始石墨烯表现出波长依赖的光响应，由于p型掺杂剂的光解吸和SiO2衬底的缺陷辅助光电离，在450 nm照射下具有明显的负光电流（NPC）。在525 nm辐照下，光子能量不足以激活表面和衬底机制，石墨烯表现出不稳定的正光电流（PPC），由弱光导驱动。相比之下，CsPbBr3/石墨烯异质结构在波长上始终表现出强大而稳定的PPC。CsPbBr3 QD的集成实现了高效的光载流子生成和转移到石墨烯通道，覆盖了寄生NPC途径并稳定了整体光响应。时间分辨测量显示异质结构的上升和下降时间明显更快，证实了从缓慢的表面介导过程到快速光导动力学的转变。这项比较研究阐明了石墨烯的固有特性、衬底相互作用和异质结效应如何共同驱动光电流极性，并提高了混合2D/0D光电探测器的性能。

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引用次数: 0

Optoelectronic logic gates and chaotic encryption optical communication enabled by dual-band optical response in a-Ga2O3/Cr2O3 heterostructures a-Ga2O3/Cr2O3异质结构中双带光响应实现光电逻辑门和混沌加密光通信

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2026-02-01 DOI: 10.1016/j.mtphys.2026.102032

Quancai Yue , Lijuan Ye , Lai Yuan, Guoping Qin, Di Pang, Yan Tang, Honglin Li, Hong Zhang, Wanjun Li

Self-powered bipolar photodetectors (PDs) have garnered significant attention for their potential in optoelectronic logic gates (OELGs) and secure optical communication systems, owing to their extremely low power consumption and cost-effectiveness. However, conventional unipolar PDs are constrained by functional rigidity and their reliance on passive decoding circuits. In this study, a self-powered bipolar photoelectrochemical detector (PEC-PD) is presented with a wavelength-dependent photoresponse in electrolytes, based on an amorphous gallium oxide/chromium oxide (a-Ga₂O₃/Cr₂O₃) p–n heterojunction. This distinctive behavior arises from variations in the competitive dynamics between interfacial redox reactions and photogenerated carrier transport at the semiconductor/electrolyte interface under short-wave ultraviolet (UV-C) and long-wave ultraviolet (UV-A) irradiation. The device exhibits a positive photocurrent response time of 82.1/91.2 ms under 254 nm illumination and a negative photocurrent response time of 9.1/13.6 ms under 380 nm without an external power supply. Utilizing this tunable photoresponse, five fundamental Boolean logic operations—“OR”, “AND”, “NOR”, “NOT”, and “NAND”—are demonstrated by tailoring the illumination at specific wavelengths. Furthermore, the distinct bipolar photocurrent behaviors enable encrypted optical communication within a single photoelectrode architecture. This study advances the understanding of carrier dynamics manipulation and provides a solid foundation for the development of multi-functional OELGs and secure optical communication systems.

由于其极低的功耗和成本效益，自供电双极光电探测器（pd）因其在光电逻辑门（OELGs）和安全光通信系统中的潜力而受到广泛关注。然而，传统的单极pd受到功能刚性和对无源解码电路的依赖的限制。在这项研究中，一种基于非晶氧化镓/氧化铬（a- ga2o3 /Cr2O3） p-n异质结的自供电双极光电电化学探测器（PEC-PD）在电解质中具有波长依赖的光响应。这种独特的行为源于在短波紫外线（UV-C）和长波紫外线（UV-A）照射下半导体/电解质界面氧化还原反应和光产生的载流子输运之间竞争动力学的变化。该器件在254 nm光照下的正光电流响应时间为82.1/91.2 ms，在没有外部电源的情况下，在380 nm光照下的负光电流响应时间为9.1/13.6 ms。利用这种可调谐的光响应，五种基本的布尔逻辑运算-“或”，“与”，“非”，“非”和“NAND”-通过剪裁特定波长的照明来演示。此外，独特的双极光电流行为使单个光电极结构内的加密光通信成为可能。该研究促进了对载流子动力学操纵的理解，为开发多功能oelg和安全光通信系统提供了坚实的基础。

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引用次数: 0

Supramolecular polymer-guided functionalization of rhenium diselenide nanosheets: Hierarchical Co-assembly and advanced performance 二硒化铼纳米片的超分子聚合物引导功能化：分层共组装和先进性能

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2026-02-01 DOI: 10.1016/j.mtphys.2026.102041

Tse-Hsin Lo , Ching-Hwa Ho , Wei-Tsung Chuang , Chih-Ping Chen , Chih-Chia Cheng

Rhenium diselenide (ReSe₂), a two-dimensional nanomaterial with excellent physical properties, holds potential for various applications. However, its performance and sustainability are severely limited by structural inhomogeneity, low electrical conductivity, and instability at high temperatures. We present an innovative approach to enhance its physical properties by combining ReSe₂ with an adenine-functionalized supramolecular polymer (AJ) to co-assemble a novel supramolecular composite system. Due to the strong affinity between the adenine groups in AJ and ReSe₂ crystals, AJ polymer chains securely attach to the ReSe₂ surface and self-assemble into hexagonal and lamellar nanostructures, which promotes stable exfoliation of ReSe₂ nanosheets and enhances the overall structural stability of the composites. Exfoliated ReSe₂ nanosheets exhibit many promising physical properties, including controllable layer number, uniform micron-sized thin nanosheet structures, distinct microscopic morphologies, and highly stable thermally reversible phase transitions and rheological behavior. Importantly, these composites exhibit significantly lower resistance and stable conductive performance compared to bulk ReSe₂ in electrochemical impedance and single-layer device evaluations, and enabled stable current conduction in devices. This newly developed system demonstrates the potential of supramolecular polymers to regulate the material properties of ReSe₂ and opens new opportunities for optoelectronics, semiconductors, and advanced technologies.

二硒化铼（ReSe2）是一种具有优异物理性能的二维纳米材料，具有广泛的应用前景。然而，其性能和可持续性受到结构不均匀性、低导电性和高温不稳定性的严重限制。我们提出了一种创新的方法，通过将ReSe2与腺嘌呤功能化的超分子聚合物（AJ）结合来共同组装一种新的超分子复合体系，以增强其物理性能。由于AJ和ReSe2晶体中的腺嘌呤基团之间具有很强的亲和力，AJ聚合物链可以安全地附着在ReSe2表面并自组装成六边形和片层状纳米结构，从而促进了ReSe2纳米片的稳定剥离，增强了复合材料的整体结构稳定性。剥离后的ReSe2纳米片具有许多有前途的物理性质，包括可控的层数、均匀的微米级薄纳米片结构、独特的微观形貌、高度稳定的热可逆相变和流变行为。重要的是，与本体ReSe2相比，这些复合材料在电化学阻抗和单层器件评估中表现出明显更低的电阻和稳定的导电性能，并使器件中的电流传导稳定。这个新开发的系统展示了超分子聚合物调节ReSe2材料特性的潜力，并为光电子、半导体和先进技术开辟了新的机会。

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引用次数: 0

Reversible thermal stiffening in polymers: A mini review 聚合物的可逆热硬化：综述

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2026-02-01 DOI: 10.1016/j.mtphys.2026.102042

Di Wu , Shuyue He , Wenbo Liu , Jason Y. Fang , Yue Wang

Conventional polymers lose mechanical properties at elevated temperatures, driving interest in polymers that show reversible heat-triggered stiffening. This review focuses on summarizing recent advances in smart polymer systems that exhibit reversible thermal stiffening, an unconventional property, where mechanical strength increases upon heating. Triggered temperature, stiffening factor, and response time are the three parameters for characterizing this behavior. We observed two primary material classes: polymer gels and solvent-free polymer melts, examining their design strategies, preparation methods, and underlying mechanisms. In gel systems, thermal stiffening is predominantly achieved upon lower critical solution temperature (LCST) polymer in solutions, while solvent-free polymer melts demonstrate more diverse and system-specific mechanisms. Although the material designs are distinguished, the reported thermal stiffening mechanisms can be summarized as reversible thermally triggered continuous polymer phases separation, denser polymer network, self-assembly polymer network, and particle network. To our knowledge, this article offers a comprehensive overview discussing various strategies for realizing thermal stiffening behavior in polymers. It also provides guidance for future developments in this emerging field of temperature-responsive smart polymer materials with self-enhanced performance capabilities.

传统聚合物在高温下会失去机械性能，这促使人们对具有可逆热致硬化特性的聚合物产生兴趣。这篇综述的重点是总结智能聚合物系统的最新进展，这些系统表现出可逆热硬化，这是一种非常规的特性，在加热时机械强度会增加。触发温度、强化系数和响应时间是表征这种行为的三个参数。我们观察了两种主要的材料类别：聚合物凝胶和无溶剂聚合物熔体，研究了它们的设计策略、制备方法和潜在的机制。在凝胶体系中，热硬化主要是在较低临界溶液温度（LCST）聚合物溶液中实现的，而无溶剂聚合物熔体则表现出更多样化和系统特异性的机制。虽然材料的设计是不同的，但报道的热强化机制可以概括为可逆的热触发连续聚合物相分离，更密集的聚合物网络，自组装聚合物网络和颗粒网络。据我们所知，这篇文章提供了一个全面的概述，讨论了实现聚合物热硬化行为的各种策略。它还为具有自我增强性能的温度响应智能聚合物材料这一新兴领域的未来发展提供了指导。

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引用次数: 0

Phase transitions, dielectric response and lattice dynamics of dimethylammonium mixed lead halide perovskites 二甲基铵混合卤化铅钙钛矿的相变、介电响应和晶格动力学

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2026-02-01 DOI: 10.1016/j.mtphys.2026.102024

Furqanul Hassan Naqvi , Syed Bilal Junaid , Jae-Hyeon Ko , Hyun Jung Kim , Hyoungjeen Jeen , Wonhyuk Shon , Seongsu Lee , Seong Heon Kim , Yeong Uk Choi , Jong Hoon Jung

Hybrid organic–inorganic perovskites exhibit rich structural dynamics that govern their stability and optoelectronic performance. Here we map the temperature-composition phase behavior of dimethylammonium lead mixed halides, DMAPbBr_3-xCl_x with x = 0, 0.5, 1.5, 2, 2.5 and 3, by combining temperature-dependent powder X-ray diffraction, Raman and Brillouin spectroscopy, dielectric spectroscopy and differential scanning calorimetry. All compositions undergo a first-order transition between an orthorhombic (P2₁2₁2₁) low-temperature phase and a hexagonal (P6₃/mmc) high-temperature phase. The transition temperature increases monotonically with Cl content at 251, 256, 265, 283, 306, and 318 K for x = 0, 0.5, 1.5, 2, 2.5, and 3, respectively. Distinct experimental signatures include: (i) abrupt hardening/softening anomalies of low-frequency Raman modes (down to 10 cm⁻¹) associated with octahedral twists and Pb–X stretching; (ii) softening of the longitudinal acoustic phonon mode and a discontinuous jump at transition temperatures in the Brillouin spectra, evidencing elastic modulus renormalization; (iii) step-like increases in the real part of the dielectric permittivity (ε₁), reflecting increased DMA reorientational polarizability and (iv) sharp DSC endotherms that quantify latent heat and confirm the first-order character. We integrate these datasets to develop a temperature–composition phase diagram for DMAPbBr_3-xCl_x and clarify how halide substitution stiffens the lattice and strengthens hydrogen-bond network to tune the transition temperature. The results provide mechanistic insight into cation–framework coupling in DMA-based perovskites and valuable insights for optimizing their structural properties to enhance device performance.

杂化有机-无机钙钛矿表现出丰富的结构动力学，这决定了它们的稳定性和光电性能。本文通过结合温度相关的粉末x射线衍射、拉曼和布里渊光谱、介电光谱和差示扫描量热法，绘制了x = 0、0.5、1.5、2、2.5和3的二甲基铵铅混合卤化物DMAPbBr3-xClx的温度-组成相行为。所有化合物都经历了正交（P212121）低温相和六方（P63/mmc）高温相之间的一阶转变。当x分别为0、0.5、1.5、2、2.5和3时，在251、256、265、283、306和318 K时，转变温度随Cl含量的增加而单调升高。不同的实验特征包括：(i)与八面体扭曲和Pb-X拉伸相关的低频拉曼模式（低至10 cm−1）的突然硬化/软化异常；（ii）纵向声子模式的软化和布里渊光谱在转变温度处的不连续跳变，证明弹性模量重整化；（iii）介电常数实部（ε1）呈阶梯状增加，反映了DMA重定向极化率的增加；（iv）明显的DSC恒温曲线量化了潜热并证实了一阶特征。我们整合这些数据集来开发DMAPbBr3-xClx的温度-组成相图，并阐明卤化物取代如何使晶格硬化并加强氢键网络以调整转变温度。研究结果为dma钙钛矿中的阳离子-框架耦合提供了机理见解，并为优化其结构特性以提高器件性能提供了有价值的见解。

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引用次数: 0

Pressure and composition tuning of structural and electronic properties of the ternary chalcohalide Pb4SeBr6 三元乙醇化物Pb4SeBr6结构和电子性能的压力和组成调谐

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2026-02-01 DOI: 10.1016/j.mtphys.2026.102036

Junhui Liang , Ying Sun , Wenbo Qiu , Shuangjiang Du , Xinglong Deng , Weizhao Cai

Chalcohalides, a class of mixed-anion semiconductors featuring both chalcogenide and halide atoms, exhibit rich structural diversity and functional properties such as strong nonlinear optical responses and ferroelectricity. Although high-pressure studies have revealed dramatic electronic transformations, including metallization and superconductivity in several chalcohalides, Pb-based systems remain largely unexplored. Here, we combine high-pressure experiments with targeted chemical substitution to investigate the structural and electronic evolution of the ternary chalcohalide Pb₄SeBr₆. We show that both physical compression and Te substitution provide effective routes to electronic-structure tuning. The derivatives Pb₄Se_1-xTe_xBr₆ (x = 0.05 and 0.18) exhibit bandgap reductions of 5.3% and 8.3%, respectively, corresponding to the effect of applying ∼5.6 GPa and ∼8.6 GPa of external pressure to the parent compound. In the parent compound, compression induces a substantial redshift of the absorption edge, narrowing the bandgap by ∼64.9% at 25.2 GPa. At ∼20.0 GPa, Pb₄SeBr₆ undergoes a first-order phase transition with the noncentrosymmetric structure retained, whereas the Te substitution (x = 0.18) produces a modest upward shift of the transition pressure to ∼22 GPa. Combined high-pressure electrical transport measurements and first-principles calculations further predict a semiconductor-to-metal transition near 90 GPa. These results demonstrate that synergistically applying physical pressure and chemical substitution provides a robust strategy for engineering electronic properties in chalcohalides, offering guidance for designing next-generation functional mixed-anion materials.

硫卤化物（Chalcohalides）是一类同时具有硫系原子和卤化物原子的混合阴离子半导体，具有丰富的结构多样性和强大的非线性光学响应和铁电性等功能特性。尽管高压研究已经揭示了剧烈的电子转变，包括几种硫化物的金属化和超导性，但基于铅的系统在很大程度上仍未被探索。在这里，我们结合高压实验和靶向化学取代来研究三元乙醇化物Pb4SeBr6的结构和电子演化。我们发现物理压缩和Te取代都为电子结构调谐提供了有效的途径。衍生物Pb4Se1-xTexBr6 （x = 0.05和0.18）分别表现出5.3%和8.3%的带隙减小，对应于对母体化合物施加~ 5.6 GPa和~ 8.6 GPa的外部压力的影响。在母体化合物中，压缩引起吸收边的大量红移，在25.2 GPa时将带隙缩小了约64.9%。在~ 20.0 GPa时，Pb4SeBr6经历了一阶相变，保留了非中心对称结构，而Te取代（x = 0.18）使转变压力适度上升到~ 22 GPa。结合高压电输运测量和第一性原理计算，进一步预测了半导体到金属的转变接近90 GPa。这些结果表明，协同施加物理压力和化学替代为设计下一代功能混合阴离子材料提供了一种强大的策略。

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引用次数: 0