Xiangtao Zou, Takahiro Watanabe, Haru Kimata, Dong Xue, Ai Shimazaki, Minh Anh Truong, Atsushi Wakamiya, Kazuhiro Marumoto
{"title":"Microscopic analysis of low but stable perovskite solar cell device performance using electron spin resonance","authors":"Xiangtao Zou, Takahiro Watanabe, Haru Kimata, Dong Xue, Ai Shimazaki, Minh Anh Truong, Atsushi Wakamiya, Kazuhiro Marumoto","doi":"10.1038/s43246-024-00675-1","DOIUrl":"10.1038/s43246-024-00675-1","url":null,"abstract":"Perovskite solar cells have attracted much attention as next-generation solar cells. However, a typical hole-transport material, spiro-OMeTAD, has associated difficulties including tedious synthesis and high cost. To overcome these shortcomings, an easily synthesized and low-cost hole-transport material has been developed: HND-2NOMe. Although HND-2NOMe has high local charge mobility because of the quasi-planar structure, its lower device performance is a weak point, the cause of which has not yet been clarified. Here, we analyse the source of the lower performance by clarifying the internal states from a microscopic viewpoint using electron spin resonance. We observe hole diffusion from perovskite to HND-2NOMe under dark conditions, indicating hole barrier formation at the perovskite/HND-2NOMe interface, leading to lower performance. Although such a barrier is formed, less hole accumulation for the HND-2NOMe-based cells under solar irradiation occurs, which is related to the stable performance. The sources of the lower but stable performance are crucially important for providing guidelines for improving the device performance. Hole-transport materials possessing high charge mobility are important in perovskite solar cells but the source of lower performance remains a mystery. Here, the microscopic mechanism for low but stable perovskite solar cell performance using these materials is analysed using electron spin resonance.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-12"},"PeriodicalIF":7.5,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00675-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142574193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Observation of converse flexoelectric effect in topological semimetals","authors":"Hidefumi Takahashi, Yusuke Kurosaka, Kenta Kimura, Akitoshi Nakano, Shintaro Ishiwata","doi":"10.1038/s43246-024-00677-z","DOIUrl":"10.1038/s43246-024-00677-z","url":null,"abstract":"A strong coupling between electric polarization and elastic deformation in solids is an important factor in creating useful electromechanical nanodevices. Such coupling is typically allowed in insulating materials with inversion symmetry breaking as exemplified by the piezoelectric effect in ferroelectric materials. Therefore, materials with metallicity and centrosymmetry have tended to be out of scope in this perspective. Here, we report the observation of giant elastic deformation by the application of an alternating electric current in topological semimetals (V,Mo)Te2, regardless of the centrosymmetry. Considering the crystal and band structures and the asymmetric measurement configurations in addition to the absence of the electromechanical effect in a trivial semimetal TiTe2, the observed effect is discussed in terms of a Berry-phase-derived converse flexoelectric effect in metals. The observation of the flexoelectric effect in topological semimetals paves a way for a new type of nanoscale electromechanical sensors and energy harvesting. A strong coupling between electric polarization and elastic deformation is important for creating electromechanical nanodevices, but such coupling typically requires inversion symmetry breaking and is elusive in metals. Here, a current-induced giant elastic deformation is reported in topological semimetals VTe2 and MoTe2, regardless of centrosymmetry, due to the Berry phase enhancement of the flexoelectric response.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-6"},"PeriodicalIF":7.5,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00677-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142574272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Substantial enhancement of perpendicular magnetic anisotropy in van der Waals ferromagnetic Fe3GaTe2 film due to pressure application","authors":"Riku Iimori, Shaojie Hu, Akihiro Mitsuda, Takashi Kimura","doi":"10.1038/s43246-024-00665-3","DOIUrl":"10.1038/s43246-024-00665-3","url":null,"abstract":"Van der Waals (vdW) two-dimensional (2D) materials have unleashed unprecedented opportunities to probe emerging physics that could be potential candidates for various functional applications. In particular, vdW 2D magnetic materials exhibit significant potential for advanced spintronic devices. Recently, Fe3GaTe2 has been discovered to possess the room-temperature ferromagnetic property with an intrinsic perpendicular magnetic anisotropy (PMA). Furthermore, considerably large anomalous Hall and Nernst angles have been reported recently. These groundbreaking findings pave the way for significant advances in high density random-access memory as well as energy harvesting devices based on spin conversion. Enhancements in the PMA and Curie temperature contribute to improved performance with reliable operation in a wide temperature range above room temperature. Moreover, the exploration of giant anomalous Hall and Nernst angles is a crucial factor for the efficient operation of spintronic devices. In this study, we demonstrate that the application of pressure to the Fe3GaTe2 2D ferromagnetic film strengthens the interlayer coupling, resulting in an improved PMA property. In addition, the application of pressure has been found to significantly increase the anomalous Hall angle. Our findings suggest that the application of pressure effectively controls the vdW interlayer coupling, thereby manipulating the ferromagnetic and spin-conversion properties of the 2D materials. Van der Waals 2D magnetic materials are promising for spintronic devices due to their tunable large anomalous Hall and Nernst angles. Here, the magneto-transport properties of Fe3GaTe2 films are investigated under pressure, demonstrating a robust perpendicular magnetic anisotropy at room temperature and an enhancement of the anomalous Hall angle.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-7"},"PeriodicalIF":7.5,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00665-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142574230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Martin Gutierrez-Amigo, Ðorđe Dangić, Chunyu Guo, Claudia Felser, Philip J. W. Moll, Maia G. Vergniory, Ion Errea
{"title":"Phonon collapse and anharmonic melting of the 3D charge-density wave in kagome metals","authors":"Martin Gutierrez-Amigo, Ðorđe Dangić, Chunyu Guo, Claudia Felser, Philip J. W. Moll, Maia G. Vergniory, Ion Errea","doi":"10.1038/s43246-024-00676-0","DOIUrl":"10.1038/s43246-024-00676-0","url":null,"abstract":"The charge-density wave (CDW) mechanism and resulting structure of the AV3Sb5 family of kagome metals has posed a puzzling challenge since their discovery four years ago. In fact, the lack of consensus on the origin and structure of the CDW hinders the understanding of the emerging phenomena. Here, by employing a non-perturbative treatment of anharmonicity from first-principles calculations, we reveal that the charge-density transition in CsV3Sb5 is driven by the large electron-phonon coupling of the material and that the melting of the CDW state is attributed to ionic entropy and lattice anharmonicity. The calculated transition temperature is in very good agreement with experiments, implying that soft mode physics are at the core of the charge-density wave transition. Contrary to the standard assumption associated with a pure kagome lattice, the CDW is essentially three-dimensional as it is triggered by an unstable phonon at the L point. The absence of involvement of phonons at the M point enables us to constrain the resulting symmetries to six possible space groups. The unusually large electron-phonon linewidth of the soft mode explains why inelastic scattering experiments did not observe any softened phonon. We foresee that large anharmonic effects are ubiquitous and could be fundamental to understand the observed phenomena also in other kagome families. The charge-density wave state in AV3Sb5 kagome metals is intimately related to several unconventional and intriguing phenomena, but its origin and structure are still under debate. Here, non-perturbative calculations indicate a large electron-phonon coupling as the driving mechanism, attributing the melting of the charge-density wave state to ionic entropy and lattice anharmonicity.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-8"},"PeriodicalIF":7.5,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00676-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142574196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Modelling freckles and spurious grain formation in directionally solidified superalloy castings","authors":"Haijie Zhang, Yunxing Zhao, Wei Xiong, Dexin Ma, Andreas Ludwig, Abdellah Kharicha, Menghuai Wu","doi":"10.1038/s43246-024-00672-4","DOIUrl":"10.1038/s43246-024-00672-4","url":null,"abstract":"Segregation channels with misoriented spurious grains, known as freckles, are an unacceptable casting defect in superalloy turbine blades. A digital-twin method to predict segregation channels was proposed in our previous studies; however, the formation of spurious grains was ignored. Here, we extend the digital twin methodology by incorporating dendrite fragmentation, which is recognized as the predominant mechanism in the formation of spurious grains. The flow-induced fragmentation process has been refined to account for the timing of dendrite pinch-off. A three-phase mixed columnar-equiaxed solidification model was used to track the motion of the crystal fragments. Directional solidification experiments for superalloy casting were conducted in an industrial-scale Bridgman furnace, and the distribution of spurious grains in the freckles was metallographically analysed. Excellent simulation-experiment-agreement was achieved. Based on this study, the formation of spurious grains within the segregation channels is mainly caused by the flow-driven fragmentation mechanism. Experimentally measured freckles can be reproduced only if the timing of the dendrite pinch-off is considered. Defect-free castings are vital to the structural integrity of superalloys used in aerospace. Here, a digital twin method is developed for modelling spurious grain formation and segregation channels in directionally solidified superalloys.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-12"},"PeriodicalIF":7.5,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11489085/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142459884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Martina Olsson, Robin Storm, Linnea Björn, Viktor Lilja, Leonard Krupnik, Yang Chen, Polina Naidjonoka, Ana Diaz, Mirko Holler, Benjamin Watts, Anette Larsson, Marianne Liebi, Aleksandar Matic
{"title":"Phase-separated polymer blends for controlled drug delivery by tuning morphology","authors":"Martina Olsson, Robin Storm, Linnea Björn, Viktor Lilja, Leonard Krupnik, Yang Chen, Polina Naidjonoka, Ana Diaz, Mirko Holler, Benjamin Watts, Anette Larsson, Marianne Liebi, Aleksandar Matic","doi":"10.1038/s43246-024-00678-y","DOIUrl":"10.1038/s43246-024-00678-y","url":null,"abstract":"Controlling drug release rate and providing physical and chemical stability to the active pharmaceutical ingredient are key properties of oral solid dosage forms. Here, we demonstrate a formulation strategy using phase-separated polymer blends where the morphology provides a route for tuning the drug release profile. By utilising phase separation of a hydrophobic and a hydrophilic polymer, the hydrophilic component will act as a channelling agent, creating a porous network upon dissolution that will dictate the release characteristics. With ptychographic X-ray tomography and scanning transmission X-ray microscopy we reveal how the morphology depends on both polymer fraction and presence of drug, and how the drug is distributed over the polymer domains. Combining X-ray imaging results with dissolution studies reveal how the morphologies are correlated with the drug release and showcase how tuning the morphology of a polymer matrix in oral formulations can be utilised as a method for controlled drug release. Drug delivery via solid oral dosage requires a controlled release rate and physical and chemical stability of the drug within the formulation. Here, X-ray tomography and spectromicroscopy reveal how the morphology of a phase-separated polymer blend controls drug release.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-8"},"PeriodicalIF":7.5,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00678-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142574267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Shrinkable muscular crystal with chemical logic gates driven by external ion environment","authors":"Jun Manabe, Mizuki Ito, Katsuya Ichihashi, Katsuya Inoue, Yin Qian, Xiao-Ming Ren, Ryo Tsunashima, Tomoyuki Akutagawa, Takayoshi Nakamura, Sadafumi Nishihara","doi":"10.1038/s43246-024-00674-2","DOIUrl":"10.1038/s43246-024-00674-2","url":null,"abstract":"Biomimetic chemical logic gates that can reversibly transform their shape and physical properties in response to their environment are an important research field. Most artificial chemical logic gates, however, rely on changes in the microscopic properties of molecules and ions in solution. Hence, developing chemical logic gates that influence macroscopic properties, such as crystal structures and magnetic and electrical properties, is essential for mimicking in vivo phenomena more accurately. Here, we develop a reset-set flip-flop circuit based on a single crystal that reversibly transforms in the presence of Ca2+ ions in aqueous solutions and is analogous to the chemical logic gate in muscles. During the crystal transformation, the lattice volume undergoes ~39% shrinkage, and the magnetic and electrical properties change considerably. Compared with existing products, the constructed crystalline system more closely resembles the function of actual muscles, which is promising for advancing the field of biomimetics. Biomimetic chemical logic gates transform in response to their environment but are currently focused on the microscopic properties. Here, a single crystal reset-set flip-flop circuit undergoes reversible volume shrinkage in response to ions in solution.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-7"},"PeriodicalIF":7.5,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00674-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142443606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yang Li, Yilun Weng, Yue Hui, Jiaqi Wang, Letao Xu, Yang Yang, Guangze Yang, Chun-Xia Zhao
{"title":"Design of stimuli-responsive minimalist heptad surfactants for stable emulsions","authors":"Yang Li, Yilun Weng, Yue Hui, Jiaqi Wang, Letao Xu, Yang Yang, Guangze Yang, Chun-Xia Zhao","doi":"10.1038/s43246-024-00670-6","DOIUrl":"10.1038/s43246-024-00670-6","url":null,"abstract":"Peptide surfactants have been extensively investigated with various applications in detergents, foods, and pharmaceutics due to their biodegradability, biocompatibility, and customizable structures. Traditional peptide surfactants are often designed in a head-to-tail fashion mimicking chemical surfactants. Alternatively, a side-by-side design pattern based on heptad repeats offers an approach to designing peptide surfactants. However, minimalist peptide design using a single heptad for stabilizing interfaces remains largely unexplored. Here, we design four heptad surfactants (AM1.2, 6H, 6H7K, and HK) responsive to metal ions and compare their emulsification performance with a three-heptad peptide, AM1. Among them, the HK peptide generates emulsions exhibiting good stability over months. We further optimize factors such as buffering salts, ionic strength, and emulsion dilutions to uncover their impacts on emulsion properties. Our findings deepen the understanding of emulsion properties and provide practical insights for characterizing peptide-based emulsions, paving the way for their broader utilization in diverse applications. Peptide surfactants are useful in detergents, foods, and pharmaceutics but their design using a single heptad remains largely unexplored. Here, four heptad surfactants were designed that are responsive to metal ions and show good emulsification properties.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-11"},"PeriodicalIF":7.5,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00670-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142443608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cancer sono-immunotherapy using a multi-metal-ligand framework","authors":"Jet-Sing M. Lee","doi":"10.1038/s43246-024-00671-5","DOIUrl":"10.1038/s43246-024-00671-5","url":null,"abstract":"Sonodynamic therapy is a precise and non-invasive anticancer treatment but is ineffective in killing cancer cells and triggering robust immune responses. Now, a dual-ligand bimetallic framework allows controlled nitric oxide release by ultrasound that is effective for sono-immunotherapy.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-3"},"PeriodicalIF":7.5,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00671-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142431084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Valentina Perricone, Ezra Sarmiento, Andrew Nguyen, Nigel C. Hughes, David Kisailus
{"title":"The convergent design evolution of multiscale biomineralized structures in extinct and extant organisms","authors":"Valentina Perricone, Ezra Sarmiento, Andrew Nguyen, Nigel C. Hughes, David Kisailus","doi":"10.1038/s43246-024-00669-z","DOIUrl":"10.1038/s43246-024-00669-z","url":null,"abstract":"Evolution has generated a sophisticated convergence of material components, ultrastructural designs, and fabrication processes in response to similar selective pressures across a diverse array of extinct and extant species. This review explores three key convergent design strategies: struts for lightweight structures with load-bearing efficiency, sutures for increased flexibility and stress management, and helicoids for impact resistance and fracture toughness. Through this examination, the review sheds light on how evolution can inspire innovative engineering approaches and technologies through the adoption of aspects of natural design. We foresee natural evolutive processes of construction as the informative harbingers of new, advanced, ecologically aware, and energy-efficient modes of human fabrication. The evolutionary process has created natural systems with structures that impart high mechanical performance, providing guidance for biomimetics. Here, the role played by three convergent design strategies – struts, sutures and helicoids – is discussed, spanning their occurrence in nature through to applications.","PeriodicalId":10589,"journal":{"name":"Communications Materials","volume":" ","pages":"1-18"},"PeriodicalIF":7.5,"publicationDate":"2024-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s43246-024-00669-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142431091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}