Pub Date : 2024-11-06DOI: 10.1016/j.mtphys.2024.101585
Wei-Tsu Peng , Jiun-Hung Yi , Chih-Cheng Cheng , Kuan-Ju Yu , Tien-Kan Chung , Ming-Chang Lu
Magnons, quantized spin waves arising from collective excitations of spins, are typically considered negligible contributors to heat transfer. However, recent studies on low-dimensional magnetic materials have challenged this notion, revealing significant magnon-mediated heat transport. The underlying physics behind this phenomenon, however, remains poorly understood. In this study, we observed a significant reduction in heat transfer in nickel nanowires under the influence of a magnetic field. Our theoretical model revealed a substantial magnon contribution of up to 30 % to nanowire heat transfer. The reduction in heat transfer under a magnetic field stemmed from a drastic decrease in the magnon mean free path (MFP). This decrease in MFP was primarily attributed to suppressing long wavelength magnons with a longer MFP. Our findings provide deeper insights into heat transfer mechanisms in nanoscale ferromagnetic materials and offer valuable guidance for the design of future spintronic devices.
{"title":"Significant magnon contribution to heat transfer in nickel nanowires","authors":"Wei-Tsu Peng , Jiun-Hung Yi , Chih-Cheng Cheng , Kuan-Ju Yu , Tien-Kan Chung , Ming-Chang Lu","doi":"10.1016/j.mtphys.2024.101585","DOIUrl":"10.1016/j.mtphys.2024.101585","url":null,"abstract":"<div><div>Magnons, quantized spin waves arising from collective excitations of spins, are typically considered negligible contributors to heat transfer. However, recent studies on low-dimensional magnetic materials have challenged this notion, revealing significant magnon-mediated heat transport. The underlying physics behind this phenomenon, however, remains poorly understood. In this study, we observed a significant reduction in heat transfer in nickel nanowires under the influence of a magnetic field. Our theoretical model revealed a substantial magnon contribution of up to 30 % to nanowire heat transfer. The reduction in heat transfer under a magnetic field stemmed from a drastic decrease in the magnon mean free path (MFP). This decrease in MFP was primarily attributed to suppressing long wavelength magnons with a longer MFP. Our findings provide deeper insights into heat transfer mechanisms in nanoscale ferromagnetic materials and offer valuable guidance for the design of future spintronic devices.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"49 ","pages":"Article 101585"},"PeriodicalIF":10.0,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.mtphys.2024.101582
Haoyu Li , Hongyi Xiao , Takeshi Egami , Yue Fan
The absence of translational symmetry in glassy materials poses a significant challenge in establishing effective structure-property relationships in real space. Consequently, the potential energy landscape (PEL) in phase space is widely utilized to comprehend the complex phenomena in glasses. The classical PEL features a two-scale profile comprising mega-basins and sub-basins, corresponding to α-relaxations (e.g. glass transition) and β-relaxations (e.g. local cage-breaking atomic rearrangements), respectively. Recent studies, however, reveal that sub-basins are not smooth and contain finer structures, the origins of which remain elusive. Here we probe the smoothness of sub-basin bottoms in glasses' PEL by introducing small intra-cage cyclic loading and then measuring the net changes in atomic-level stresses. Compared to glasses with pair interaction, glasses with many-body interaction exhibit orders-of-magnitude larger and loading-dependent stress changes even before the first cage-breaking event takes place, which reflect much more feature-rich sub-basins. We further demonstrate this stark contrast stems from the spatial distribution of individual atom's constraining force field. Specifically, at vanishing perturbations, many-body interactions disrupt the positive-definite synchrony in energy variations of the perturbed atom and the whole system, causing inherently less confined atomic responses and infinitely rugged sub-basins. The implications of these findings for the selective addition or removal of fine structures in the PEL and the subsequent tuning of glassy materials' responses to external stimuli are also explored.
玻璃材料不存在平移对称性，这给在实际空间中建立有效的结构-性能关系带来了巨大挑战。因此，相空间势能图（PEL）被广泛用于理解玻璃中的复杂现象。经典的势能图具有双尺度剖面，包括巨盆地和子盆地，分别对应于α-松弛（如玻璃转变）和β-松弛（如局部破笼原子重排）。然而，最近的研究发现，亚盆地并不光滑，它包含更精细的结构，而这些结构的起源仍然难以捉摸。在此，我们通过引入小的笼内循环加载，然后测量原子级应力的净变化，来探究玻璃 PEL 中子盆地底部的平滑性。与具有配对相互作用的玻璃相比，具有多体相互作用的玻璃甚至在第一次破笼事件发生之前就表现出了数量级更大且与加载相关的应力变化，这反映了特征更为丰富的子盆地。我们进一步证明，这种鲜明对比源于单个原子约束力场的空间分布。具体来说，在扰动消失时，多体相互作用会破坏受扰动原子和整个系统能量变化的正无限同步性，从而导致原子反应的内在约束性降低和子盆地的无限崎岖。此外，还探讨了这些发现对选择性添加或去除 PEL 中的精细结构以及随后调整玻璃材料对外部刺激的反应的影响。
{"title":"Infinitely rugged intra-cage potential energy landscape in metallic glasses caused by many-body interaction","authors":"Haoyu Li , Hongyi Xiao , Takeshi Egami , Yue Fan","doi":"10.1016/j.mtphys.2024.101582","DOIUrl":"10.1016/j.mtphys.2024.101582","url":null,"abstract":"<div><div>The absence of translational symmetry in glassy materials poses a significant challenge in establishing effective structure-property relationships in real space. Consequently, the potential energy landscape (PEL) in phase space is widely utilized to comprehend the complex phenomena in glasses. The classical PEL features a two-scale profile comprising mega-basins and sub-basins, corresponding to α-relaxations (<em>e.g.</em> glass transition) and β-relaxations (<em>e.g.</em> local cage-breaking atomic rearrangements), respectively. Recent studies, however, reveal that sub-basins are not smooth and contain finer structures, the origins of which remain elusive. Here we probe the smoothness of sub-basin bottoms in glasses' PEL by introducing small intra-cage cyclic loading and then measuring the net changes in atomic-level stresses. Compared to glasses with pair interaction, glasses with many-body interaction exhibit orders-of-magnitude larger and loading-dependent stress changes even before the first cage-breaking event takes place, which reflect much more feature-rich sub-basins. We further demonstrate this stark contrast stems from the spatial distribution of individual atom's constraining force field. Specifically, at vanishing perturbations, many-body interactions disrupt the positive-definite synchrony in energy variations of the perturbed atom and the whole system, causing inherently less confined atomic responses and infinitely rugged sub-basins. The implications of these findings for the selective addition or removal of fine structures in the PEL and the subsequent tuning of glassy materials' responses to external stimuli are also explored.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"49 ","pages":"Article 101582"},"PeriodicalIF":10.0,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142594296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.mtphys.2024.101580
Rutao Meng , Xuejun Xu , Yue Huang , Li Wu , Jianpeng Li , Han Xu , Jiabin Dong , Yue Liu , Xuewen Fu , Hongling Guo , Gang Wang , Yi Zhang
Kesterite solar cells show great potential for sustainable photovoltaic technology, attributed to their excellent semiconductor properties and earth abundant composition. However, undesirable band bending at the grain boundaries (GBs) in Cu2ZnSn(S,Se)4 (CZTSSe) films induces serious carrier recombination because of inhomogeneous distribution of S and Se in the grain interiors (GIs) and at GBs, which results in large open-circuit voltage deficit and overall poor performance of CZTSSe solar cells. Here, a robust hydrothermal sulfurization design has successfully inverted the band bending at the GBs, with advanced cathodoluminescence measurement confirming the transition of carrier collection pathways from the GBs to the GIs, thereby achieving efficient carrier collection within the GIs. Simultaneously, this design has effectively passivated the non-radiative recombination in the GIs, smoothing the way for carrier collection. Ultimately, a 13.7 % efficiency CZTSSe solar cell with 44 % improvement is realized by this process. This study discloses that reversing the band bending at GBs is practical to tailor the carrier collection, and thus pave the pathway for high-efficient photoelectronic devices.
{"title":"Reversing band bending at grain boundaries enables high-efficiency Cu2ZnSn(S,Se)4 solar cells","authors":"Rutao Meng , Xuejun Xu , Yue Huang , Li Wu , Jianpeng Li , Han Xu , Jiabin Dong , Yue Liu , Xuewen Fu , Hongling Guo , Gang Wang , Yi Zhang","doi":"10.1016/j.mtphys.2024.101580","DOIUrl":"10.1016/j.mtphys.2024.101580","url":null,"abstract":"<div><div>Kesterite solar cells show great potential for sustainable photovoltaic technology, attributed to their excellent semiconductor properties and earth abundant composition. However, undesirable band bending at the grain boundaries (GBs) in Cu<sub>2</sub>ZnSn(S,Se)<sub>4</sub> (CZTSSe) films induces serious carrier recombination because of inhomogeneous distribution of S and Se in the grain interiors (GIs) and at GBs, which results in large open-circuit voltage deficit and overall poor performance of CZTSSe solar cells. Here, a robust hydrothermal sulfurization design has successfully inverted the band bending at the GBs, with advanced cathodoluminescence measurement confirming the transition of carrier collection pathways from the GBs to the GIs, thereby achieving efficient carrier collection within the GIs. Simultaneously, this design has effectively passivated the non-radiative recombination in the GIs, smoothing the way for carrier collection. Ultimately, a 13.7 % efficiency CZTSSe solar cell with 44 % improvement is realized by this process. This study discloses that reversing the band bending at GBs is practical to tailor the carrier collection, and thus pave the pathway for high-efficient photoelectronic devices.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"48 ","pages":"Article 101580"},"PeriodicalIF":10.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142541509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.mtphys.2024.101554
Tyler C. Sterling , Feng Ye , Seohyeon Jo , Anish Parulekar , Yu Zhang , Gang Cao , Rishi Raj , Dmitry Reznik
{"title":"Corrigendum to “Structural and electronic transformations in TiO2 induced by electric current” [Mater. Today Phys., 48 (November 2024), 101546]","authors":"Tyler C. Sterling , Feng Ye , Seohyeon Jo , Anish Parulekar , Yu Zhang , Gang Cao , Rishi Raj , Dmitry Reznik","doi":"10.1016/j.mtphys.2024.101554","DOIUrl":"10.1016/j.mtphys.2024.101554","url":null,"abstract":"","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"48 ","pages":"Article 101554"},"PeriodicalIF":10.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Germanium Telluride (GeTe) has been widely explored as a promising lead-free thermoelectric material in its rhombohedral and cubic phases. However, the structural transition between these two phases at ∼700 K causes an abrupt change of thermal expansion coefficient, challenging its broader practical applications. Also, as characterized by multi-valence bands and strong anharmonic interaction, the high-temperature cubic phase exhibits a higher power factor, lower thermal conductivity, and ultimately superior thermoelectric performance than its rhombohedral counterpart. Prompted by these, in this work, the cubic phase of Ge0.9Sb0.1Te (presented as GeSbTe in the following content) nanocrystalline thin film is successfully realized by RF sputtering followed by post-annealing treatment. Additionally, indium, as an electron donor to the germanium site and an effective scattering center, further moderates carrier concentration, enhances the Seebeck coefficient and reduces thermal conductivity. The optimal composition achieves an estimated peak of ∼1.95 and an estimated average of ∼1.11 within the temperature range of 300 K–575 K, showcasing GeTe as a compelling candidate for applications close to room temperature.
碲化镉锗（GeTe）的斜方体相和立方体相作为一种前景广阔的无铅热电材料已被广泛探索。然而，这两种相在 ∼700 K 时的结构转变会导致热膨胀系数的突然变化，这对其更广泛的实际应用提出了挑战。此外，高温立方相具有多价带和强非谐相互作用的特点，与斜方体相相比，其功率因数更高，热导率更低，热电性能更优。有鉴于此，在这项工作中，通过射频溅射和退火后处理，成功实现了 Ge0.9Sb0.1Te（下文中称为 GeSbTe）纳米晶薄膜的立方相。此外，铟作为锗位点的电子供体和有效的散射中心，进一步缓和了载流子浓度，提高了塞贝克系数并降低了热导率。在 300 K 至 575 K 的温度范围内，最佳成分的峰值估计为 ∼ 1.95，平均值估计为 ∼ 1.11，这表明 GeTe 是接近室温应用的理想候选材料。
{"title":"Synergistic effect of indium doping on thermoelectric performance of cubic GeTe-based thin films","authors":"Suman Abbas , Bhawna Jarwal , Thi-Thong Ho , Suneesh Meledath Valiyaveettil , Cheng-Rong Hsing , Ta-Lei Chou , Ching-Ming Wei , Li-Chyong Chen , Kuei-Hsien Chen","doi":"10.1016/j.mtphys.2024.101581","DOIUrl":"10.1016/j.mtphys.2024.101581","url":null,"abstract":"<div><div>Germanium Telluride (GeTe) has been widely explored as a promising lead-free thermoelectric material in its rhombohedral and cubic phases. However, the structural transition between these two phases at ∼700 K causes an abrupt change of thermal expansion coefficient, challenging its broader practical applications. Also, as characterized by multi-valence bands and strong anharmonic interaction, the high-temperature cubic phase exhibits a higher power factor, lower thermal conductivity, and ultimately superior thermoelectric performance than its rhombohedral counterpart. Prompted by these, in this work, the cubic phase of Ge<sub>0.9</sub>Sb<sub>0.1</sub>Te (presented as GeSbTe in the following content) nanocrystalline thin film is successfully realized by RF sputtering followed by post-annealing treatment. Additionally, indium, as an electron donor to the germanium site and an effective scattering center, further moderates carrier concentration, enhances the Seebeck coefficient and reduces thermal conductivity. The optimal composition achieves an estimated peak <span><math><mrow><mi>z</mi><mi>T</mi></mrow></math></span> of ∼1.95 and an estimated average <span><math><mrow><mi>z</mi><mi>T</mi></mrow></math></span> of ∼1.11 within the temperature range of 300 K–575 K, showcasing GeTe as a compelling candidate for applications close to room temperature.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"49 ","pages":"Article 101581"},"PeriodicalIF":10.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142562243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-28DOI: 10.1016/j.mtphys.2024.101579
Xuqing Zhang , Yongping Pu , Pan Gao , Xinye Huang , Jiahui Ma , Lei Zhang , Zenghui Liu
High energy-density (Wrec) dielectric capacitors have gained a focal point in the field of power electronic systems. In this study, high energy storage density materials with near-zero loss were obtained by constructing different types of defect dipoles in linear dielectric ceramics. Mg2+and Nb5+ are strategically chosen as acceptor/donor ions, effectively replacing Ti4+ within Ca0.5Sr0.5TiO3-based ceramics. The results indicate that under an applied electric field, specific defects such as and , can effectively regulate and electron movement, significantly reducing losses. Furthermore, high-density insulating grain boundaries, reduced concentrations and diminished carrier mobility contribute to enhanced resistivity, resulting in high Wrec ∼7.62 J/cm3 and η ∼92 % at 640 kV/cm, making it one of the most promising linear dielectrics to date. Notably, Wrec and η remain remarkably stable across a broad range of frequencies (1–500 Hz), temperatures (25–175 °C) and numerous cycles (up to 106). Additionally, finite element software was used to simulate the distribution of dielectric constant, electric potential, and local electric field, further verifying the correlation between microstructure and breakdown resistance. This innovative work provides a sustainable strategy to optimize the energy storage capacity of lead-free ceramics over a wide temperature range through strategic manipulation of defects.
{"title":"Linear dielectric ceramics for near-zero loss high-capacitance energy storage","authors":"Xuqing Zhang , Yongping Pu , Pan Gao , Xinye Huang , Jiahui Ma , Lei Zhang , Zenghui Liu","doi":"10.1016/j.mtphys.2024.101579","DOIUrl":"10.1016/j.mtphys.2024.101579","url":null,"abstract":"<div><div>High energy-density (<em>W</em><sub>rec</sub>) dielectric capacitors have gained a focal point in the field of power electronic systems. In this study, high energy storage density materials with near-zero loss were obtained by constructing different types of defect dipoles in linear dielectric ceramics. Mg<sup>2+</sup>and Nb<sup>5+</sup> are strategically chosen as acceptor/donor ions, effectively replacing Ti<sup>4+</sup> within Ca<sub>0.5</sub>Sr<sub>0.5</sub>TiO<sub>3</sub>-based ceramics. The results indicate that under an applied electric field, specific defects such as <span><math><mrow><mo>[</mo><mrow><msubsup><mrow><mi>M</mi><mi>g</mi></mrow><mrow><mi>T</mi><mi>i</mi></mrow><mo>″</mo></msubsup><mo>−</mo><msubsup><mi>V</mi><mi>O</mi><mrow><mo>·</mo><mo>·</mo></mrow></msubsup></mrow><mo>]</mo></mrow></math></span> and <span><math><mrow><mrow><msubsup><mrow><mo>[</mo><mi>N</mi><mi>b</mi></mrow><mrow><mi>T</mi><mi>i</mi></mrow><mo>·</mo></msubsup><mo>−</mo><msup><mrow><mi>T</mi><mi>i</mi></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></mrow><mo>]</mo></mrow></math></span>, can effectively regulate <span><math><mrow><msubsup><mi>V</mi><mi>O</mi><mrow><mo>·</mo><mo>·</mo></mrow></msubsup></mrow></math></span> and electron movement, significantly reducing losses. Furthermore, high-density insulating grain boundaries, reduced <span><math><mrow><msubsup><mi>V</mi><mi>O</mi><mrow><mo>·</mo><mo>·</mo></mrow></msubsup></mrow></math></span> concentrations and diminished carrier mobility contribute to enhanced resistivity, resulting in high <em>W</em><sub>rec</sub> ∼7.62 J/cm<sup>3</sup> and <em>η</em> ∼92 % at 640 kV/cm, making it one of the most promising linear dielectrics to date. Notably, <em>W</em><sub>rec</sub> and <em>η</em> remain remarkably stable across a broad range of frequencies (1–500 Hz), temperatures (25–175 °C) and numerous cycles (up to 10<sup>6</sup>). Additionally, finite element software was used to simulate the distribution of dielectric constant, electric potential, and local electric field, further verifying the correlation between microstructure and breakdown resistance. This innovative work provides a sustainable strategy to optimize the energy storage capacity of lead-free ceramics over a wide temperature range through strategic manipulation of defects.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"49 ","pages":"Article 101579"},"PeriodicalIF":10.0,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142520125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The development of lightweight and highly heat-resistant polyimide foams (PIFs) remains a great challenge in areas of aerospace, military ships, transportation, and industries. Herein, a series of lightweight and highly thermal-resistant copolymerized PIFs are successfully fabricated by the “stepwise heating-holding” thermal foaming of the copolymerized polyester ammonium salts (C-PEAS), using 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride (BTDA) and 2,3,3′,4′-biphenyl tetracarboxylic acid dianhydride (α-BPDA) as codianhydride, and p-phenylenediamine (PDA) as diamine. The introduction of α-BPDA increases the rigidity of PI molecule chains and foamability of C-PEAS, and significantly improves the heat resistance of PIFs. The resultant copolymerized PIFs exhibit ultra-low densities (<10 kg m−3), excellent heat resistance (Tg ranging from 351.2 °C to 405.6 °C), and high thermal stability. Moreover, they possess high flame retardancies (LOI>44 %) and low thermal conductivities (as low as 0.0463 W m−1 K−1 at 20 °C and no more than 0.0825 W m−1 K−1 at 200 °C), demonstrating their excellent thermal insulation properties in a wide temperature range. After the continuous heating at 200 °C for 40 min, the upper surface of PIFs present low average temperatures less than 60 °C. Additionally, the copolymerized PIFs exhibit remarkable acoustic properties with average acoustic absorption coefficients above 0.6 and noise reduction coefficients (NRC) above 0.3. Therefore, the lightweight and highly heat-resistant copolymerized PIFs show great application potentials in the extreme environments of aerospace, military ships, transportation, and industries.
{"title":"Lightweight and highly heat-resistant copolymerized polyimide foams for superior thermal insulation and acoustic absorption","authors":"Shuhuan Yun, Xianzhe Sheng, Zhenyu Xiong, Zhonglei Ma, Jianbing Qin, Guangcheng Zhang","doi":"10.1016/j.mtphys.2024.101578","DOIUrl":"10.1016/j.mtphys.2024.101578","url":null,"abstract":"<div><div>The development of lightweight and highly heat-resistant polyimide foams (PIFs) remains a great challenge in areas of aerospace, military ships, transportation, and industries. Herein, a series of lightweight and highly thermal-resistant copolymerized PIFs are successfully fabricated by the “stepwise heating-holding” thermal foaming of the copolymerized polyester ammonium salts (C-PEAS), using 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride (BTDA) and 2,3,3′,4′-biphenyl tetracarboxylic acid dianhydride (α-BPDA) as codianhydride, and p-phenylenediamine (PDA) as diamine. The introduction of α-BPDA increases the rigidity of PI molecule chains and foamability of C-PEAS, and significantly improves the heat resistance of PIFs. The resultant copolymerized PIFs exhibit ultra-low densities (<10 kg m<sup>−3</sup>), excellent heat resistance (<em>T</em><sub>g</sub> ranging from 351.2 °C to 405.6 °C), and high thermal stability. Moreover, they possess high flame retardancies (LOI>44 %) and low thermal conductivities (as low as 0.0463 W m<sup>−1</sup> K<sup>−1</sup> at 20 °C and no more than 0.0825 W m<sup>−1</sup> K<sup>−1</sup> at 200 °C), demonstrating their excellent thermal insulation properties in a wide temperature range. After the continuous heating at 200 °C for 40 min, the upper surface of PIFs present low average temperatures less than 60 °C. Additionally, the copolymerized PIFs exhibit remarkable acoustic properties with average acoustic absorption coefficients above 0.6 and noise reduction coefficients (NRC) above 0.3. Therefore, the lightweight and highly heat-resistant copolymerized PIFs show great application potentials in the extreme environments of aerospace, military ships, transportation, and industries.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"49 ","pages":"Article 101578"},"PeriodicalIF":10.0,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-23DOI: 10.1016/j.mtphys.2024.101576
Tianhui Jiang , Chunnan Wang , Tianyi Ling , Shuqing Sun , Lei Yang
Global research on flexible pressure sensors for evaluating human wellness and intelligent robotics is intensifying due to their advantages of excellent flexibility, lightweight design, high sensitivity and ease of integration. To facilitate practical applications, challenges associated with high-performance must be addressed, such as the trade-off between high sensitivity and a wide linear sensing range, fast response/recovery time, limited hysteresis, and stability under both dynamic and static pressure conditions. Moreover, ensuring the sensors’ reliability under various interferences and their multi-functionality to meet diverse usage requirements is essential for future applications. In this review, we summarize the latest advancements in multiple microstructures within the active layer and/or electrodes, which ensure excellent sensing performances, superior reliability and multifunctional features. Specifically, we focus on the design, working principles and sensing features of advanced micropattern, micropores, fiber-network, and hybrid microstructures in pressure sensors based on hierarchical micro-/nano-structure, conductive gradient coatings or multilayer structures. Additionally, the applications of microstructured pressure sensors in the fields of healthcare and human-machine interaction are summarized. Finally, we discuss the challenges and future prospects in the development of the next generation of flexible pressure sensors.
{"title":"Recent advances and new frontier of flexible pressure sensors: Structure engineering, performances and applications","authors":"Tianhui Jiang , Chunnan Wang , Tianyi Ling , Shuqing Sun , Lei Yang","doi":"10.1016/j.mtphys.2024.101576","DOIUrl":"10.1016/j.mtphys.2024.101576","url":null,"abstract":"<div><div>Global research on flexible pressure sensors for evaluating human wellness and intelligent robotics is intensifying due to their advantages of excellent flexibility, lightweight design, high sensitivity and ease of integration. To facilitate practical applications, challenges associated with high-performance must be addressed, such as the trade-off between high sensitivity and a wide linear sensing range, fast response/recovery time, limited hysteresis, and stability under both dynamic and static pressure conditions. Moreover, ensuring the sensors’ reliability under various interferences and their multi-functionality to meet diverse usage requirements is essential for future applications. In this review, we summarize the latest advancements in multiple microstructures within the active layer and/or electrodes, which ensure excellent sensing performances, superior reliability and multifunctional features. Specifically, we focus on the design, working principles and sensing features of advanced micropattern, micropores, fiber-network, and hybrid microstructures in pressure sensors based on hierarchical micro-/nano-structure, conductive gradient coatings or multilayer structures. Additionally, the applications of microstructured pressure sensors in the fields of healthcare and human-machine interaction are summarized. Finally, we discuss the challenges and future prospects in the development of the next generation of flexible pressure sensors.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"48 ","pages":"Article 101576"},"PeriodicalIF":10.0,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142487158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-22DOI: 10.1016/j.mtphys.2024.101577
Yang Zhao , Zihao Guan , Zhiyuan Wei , Lulu Fu , Lu Chen , Zhipeng Huang , Mark G. Humphrey , Chi Zhang
The surface terminations (=O, -OH, and -F) play a key role in determining the physical and chemical properties of MXenes, which have been demonstrated with significant potential in field-effect transistors, humidity sensors, energy storage, and photocatalysis, etc. It is therefore crucial to modify these active functional groups on the surface of MXenes in order to optimize the applicability of these materials. In this study, we introduce a covalent modification strategy to successfully construct a porphyrin-functionalized Ti3C2Tx organic-inorganic nanohybrid (TPP-Ti3C2Tx) by covalently attaching porphyrin molecules to the surface groups on Ti3C2Tx nanosheets for the first time. As revealed by steady-state fluorescence spectra, transient fluorescence spectra, and DFT calculations, the robust covalent bonds between TPP and Ti3C2Tx can effectively promote the photon-induced electron and/or energy transfer within the TPP-Ti3C2Tx nanohybrid. The investigation on the nonlinear optical (NLO) properties of TPP-Ti3C2Tx nanohybrid as well as its precursors, reveals that the TPP-Ti3C2Tx nanohybrid exhibits the highest nonlinear absorption coefficient and the lowest optical limiting threshold among the tested samples at both 532 and 1064 nm, indicating its great potential as a broadband optical limiter for visible and near-infrared wavelengths. This work not only demonstrates the significant promise of covalently-linked TPP-Ti3C2Tx nanohybrid in optical limiting applications but also provides a paradigm for engineering high-performance NLO MXenes-based materials through the covalent modification strategy.
{"title":"Enhanced nonlinear optical properties of MXene (Ti3C2Tx) via surface-covalent functionalization with porphyrin","authors":"Yang Zhao , Zihao Guan , Zhiyuan Wei , Lulu Fu , Lu Chen , Zhipeng Huang , Mark G. Humphrey , Chi Zhang","doi":"10.1016/j.mtphys.2024.101577","DOIUrl":"10.1016/j.mtphys.2024.101577","url":null,"abstract":"<div><div>The surface terminations (=O, -OH, and -F) play a key role in determining the physical and chemical properties of MXenes, which have been demonstrated with significant potential in field-effect transistors, humidity sensors, energy storage, and photocatalysis, etc. It is therefore crucial to modify these active functional groups on the surface of MXenes in order to optimize the applicability of these materials. In this study, we introduce a covalent modification strategy to successfully construct a porphyrin-functionalized Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> organic-inorganic nanohybrid (TPP-Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub>) by covalently attaching porphyrin molecules to the surface groups on Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> nanosheets for the first time. As revealed by steady-state fluorescence spectra, transient fluorescence spectra, and DFT calculations, the robust covalent bonds between TPP and Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> can effectively promote the photon-induced electron and/or energy transfer within the TPP-Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> nanohybrid. The investigation on the nonlinear optical (NLO) properties of TPP-Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> nanohybrid as well as its precursors, reveals that the TPP-Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> nanohybrid exhibits the highest nonlinear absorption coefficient and the lowest optical limiting threshold among the tested samples at both 532 and 1064 nm, indicating its great potential as a broadband optical limiter for visible and near-infrared wavelengths. This work not only demonstrates the significant promise of covalently-linked TPP-Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> nanohybrid in optical limiting applications but also provides a paradigm for engineering high-performance NLO MXenes-based materials through the covalent modification strategy.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"48 ","pages":"Article 101577"},"PeriodicalIF":10.0,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142487089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-22DOI: 10.1016/j.mtphys.2024.101575
Tian He , Kang-Hong Yin , Xin-Sheng Gao , Han-Xi Ren , Ya-Xun He , Jia-Ying Zhang , Hao-Hao Shi , Cun Xue , Jun-Yi Ge
Most superconducting electronics based on films exhibit granular structures. It has been suggested that grain boundaries form a network with relatively weak superconductivity, potentially acting as pinning centers. Yet, so far, detailed microscopic studies of the pinning landscape and its relation to vortex behavior remain scarce. Here, we imaged the vortex lattices (VL) in granular Nb films using magnetic force microscopy over large scanning areas at various magnetic fields. A non-monotonic evolution in the degree of vortex lattice ordering was observed with increasing vortex density, driven by a combination of vortex-vortex interactions and pinning effects. The spatial distribution of pinning potential within the film was directly mapped using a recently developed scanning quantum vortex microscope (SQVM). Instead of the network formed by grain boundaries, the pinning landscape presents a network-like structure, yet with domains significantly larger than the individual grains. The results of numerical simulations based on pinning landscape revealed by SQVM well reproduce our experiments. The pinning force per unit length at low magnetic fields was calculated. The critical current density, estimated from the relative positions of vortices, aligns well with the critical state model. Our work illustrates the relationship between the evolution of the vortex lattice with magnetic field and the structural features of granular Nb film, providing new insights into the design of high-performance superconducting electronic devices.
{"title":"Revealing the pinning landscape and related vortex pattern evolution in granular superconducting films","authors":"Tian He , Kang-Hong Yin , Xin-Sheng Gao , Han-Xi Ren , Ya-Xun He , Jia-Ying Zhang , Hao-Hao Shi , Cun Xue , Jun-Yi Ge","doi":"10.1016/j.mtphys.2024.101575","DOIUrl":"10.1016/j.mtphys.2024.101575","url":null,"abstract":"<div><div>Most superconducting electronics based on films exhibit granular structures. It has been suggested that grain boundaries form a network with relatively weak superconductivity, potentially acting as pinning centers. Yet, so far, detailed microscopic studies of the pinning landscape and its relation to vortex behavior remain scarce. Here, we imaged the vortex lattices (VL) in granular Nb films using magnetic force microscopy over large scanning areas at various magnetic fields. A non-monotonic evolution in the degree of vortex lattice ordering was observed with increasing vortex density, driven by a combination of vortex-vortex interactions and pinning effects. The spatial distribution of pinning potential within the film was directly mapped using a recently developed scanning quantum vortex microscope (SQVM). Instead of the network formed by grain boundaries, the pinning landscape presents a network-like structure, yet with domains significantly larger than the individual grains. The results of numerical simulations based on pinning landscape revealed by SQVM well reproduce our experiments. The pinning force per unit length at low magnetic fields was calculated. The critical current density, estimated from the relative positions of vortices, aligns well with the critical state model. Our work illustrates the relationship between the evolution of the vortex lattice with magnetic field and the structural features of granular Nb film, providing new insights into the design of high-performance superconducting electronic devices.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"48 ","pages":"Article 101575"},"PeriodicalIF":10.0,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142487075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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