Chemiresistive materials, which alter their electrical resistance in response to interactions with surrounding chemicals, are valued for their robustness, rapid detection ability and high sensitivity. Recent research has revealed that the sensing performance of these materials can be enhanced by applying an external magnetic field. In this study, we report a novel finding in the chemiresistive behaviour of magnetite (Fe3O4), where its response has been found to be modulated in an anisotropic manner when exposed to an external magnetic field, analogous to Earth's magnetic field. Remarkably, substantial variations have been observed in response to analytes naturally present in the atmosphere. A remarkable increase in response was observed upon applying a 0.05 mT magnetic field, resulting in a more than 26-fold enhancement in sensitivity to relative humidity (98%), as well as a greater than 10-fold improvement in response to CO2 and a 25-fold increase in response to NO2. This chemiresistive response exhibits a strong anisotropic dependence on the strength, direction and inclination of the magnetic field, suggesting that magnetite's electrical resistance dynamically adapts to both magnetic and chemical environmental changes. The observed behaviour under an Earth-like magnetic field closely mirrors the magnetoreception seen in biological species that rely on magnetite for navigation. This finding may provide new insights into the mechanisms behind magnetite-based magnetoreception observed in various biological species.
{"title":"Discovery of magnetic field line dependent anisotropic chemiresistive response in magnetite: a new piece to the puzzle of magnetoreception.","authors":"Pratyasha Rudra, Swastik Mondal","doi":"10.1039/d4mh01752h","DOIUrl":"https://doi.org/10.1039/d4mh01752h","url":null,"abstract":"<p><p>Chemiresistive materials, which alter their electrical resistance in response to interactions with surrounding chemicals, are valued for their robustness, rapid detection ability and high sensitivity. Recent research has revealed that the sensing performance of these materials can be enhanced by applying an external magnetic field. In this study, we report a novel finding in the chemiresistive behaviour of magnetite (Fe<sub>3</sub>O<sub>4</sub>), where its response has been found to be modulated in an anisotropic manner when exposed to an external magnetic field, analogous to Earth's magnetic field. Remarkably, substantial variations have been observed in response to analytes naturally present in the atmosphere. A remarkable increase in response was observed upon applying a 0.05 mT magnetic field, resulting in a more than 26-fold enhancement in sensitivity to relative humidity (98%), as well as a greater than 10-fold improvement in response to CO<sub>2</sub> and a 25-fold increase in response to NO<sub>2</sub>. This chemiresistive response exhibits a strong anisotropic dependence on the strength, direction and inclination of the magnetic field, suggesting that magnetite's electrical resistance dynamically adapts to both magnetic and chemical environmental changes. The observed behaviour under an Earth-like magnetic field closely mirrors the magnetoreception seen in biological species that rely on magnetite for navigation. This finding may provide new insights into the mechanisms behind magnetite-based magnetoreception observed in various biological species.</p>","PeriodicalId":87,"journal":{"name":"Materials Horizons","volume":" ","pages":""},"PeriodicalIF":12.2,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143603220","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}
Bin Xu, Touchy Abeda Sultana, Koki Kitai, Jiang Guo, Toyomitsu Seki, Ryo Tamura, Koji Tsuda, Junichiro Shiomi
"Fifth-generation-and-beyond" communication technologies have sparked considerable demand for polymer composite materials with low coefficients of thermal expansion (CTE) and low dielectric loss at high operation frequencies. However, the complexity of process parameters and the lack of knowledge about fabrication procedures hinder this goal. In this study, state-of-the-art experiment-in-loop Bayesian optimization (EiL-BO) was developed to optimize a composite of a perfluoroalkoxyalkane matrix with silica fillers. The Gaussian process equipped with an automatic relevance determination kernel that automatically adjusts the scaling parameters of individual dimensions effectively enhances EiL-BO's ability to search for candidates in a complex and anisotropic multidimensional space. This addresses the critical challenge of handling problems with high-dimensional parameters and is capable of managing eight-dimensional parameters, including filler morphology, surface chemistry, and compounding process parameters. The obtained optimal composite shows a low CTE of 24.7 ppm K-1 and an extinction coefficient of 9.5 × 10-4, outperforming the existing polymeric composite, revealing exceptionally effective and versatile EiL-BO that accelerates the development of advanced materials.
{"title":"Experiment-in-loop interactive optimization of polymer composites for \"5G-and-beyond\" communication technologies.","authors":"Bin Xu, Touchy Abeda Sultana, Koki Kitai, Jiang Guo, Toyomitsu Seki, Ryo Tamura, Koji Tsuda, Junichiro Shiomi","doi":"10.1039/d4mh01606h","DOIUrl":"https://doi.org/10.1039/d4mh01606h","url":null,"abstract":"<p><p>\"Fifth-generation-and-beyond\" communication technologies have sparked considerable demand for polymer composite materials with low coefficients of thermal expansion (CTE) and low dielectric loss at high operation frequencies. However, the complexity of process parameters and the lack of knowledge about fabrication procedures hinder this goal. In this study, state-of-the-art experiment-in-loop Bayesian optimization (EiL-BO) was developed to optimize a composite of a perfluoroalkoxyalkane matrix with silica fillers. The Gaussian process equipped with an automatic relevance determination kernel that automatically adjusts the scaling parameters of individual dimensions effectively enhances EiL-BO's ability to search for candidates in a complex and anisotropic multidimensional space. This addresses the critical challenge of handling problems with high-dimensional parameters and is capable of managing eight-dimensional parameters, including filler morphology, surface chemistry, and compounding process parameters. The obtained optimal composite shows a low CTE of 24.7 ppm K<sup>-1</sup> and an extinction coefficient of 9.5 × 10<sup>-4</sup>, outperforming the existing polymeric composite, revealing exceptionally effective and versatile EiL-BO that accelerates the development of advanced materials.</p>","PeriodicalId":87,"journal":{"name":"Materials Horizons","volume":" ","pages":""},"PeriodicalIF":12.2,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143584030","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}
Our Emerging Investigator Series features exceptional work by early-career researchers working in the field of materials science.
{"title":"Materials Horizons Emerging Investigator Series: Dr Dibyajyoti Ghosh and Dr Satyaprasad P. Senanayak, Indian Institute of Technology, Delhi and National Institute of Science Education and Research, India","authors":"","doi":"10.1039/D5MH90027A","DOIUrl":"10.1039/D5MH90027A","url":null,"abstract":"<p >Our Emerging Investigator Series features exceptional work by early-career researchers working in the field of materials science.</p>","PeriodicalId":87,"journal":{"name":"Materials Horizons","volume":" 7","pages":" 2038-2039"},"PeriodicalIF":12.2,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143584029","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}
Johan Liotier, Antonio J Riquelme, Valid Mwalukuku, Quentin Huaulmé, Yann Kervella, Renaud Demadrille, Cyril Aumaître
Because they can be made semi-transparent, dye-sensitised solar cells (DSSCs) have great potential for glazing applications. Their photovoltaic performance and light transmission depend not only on the dye used, but also on the electrolyte they contain. A few years ago, we introduced the concept of solar cells with dynamic optical properties based on the use of photochromic photosensitizers. These cells allow variable light transmission according to sunlight conditions, while producing electrical energy. We found that the electrolytes commonly used in DSSCs are not optimal for this class of photosensitisers and need to be tuned. In this work, we have developed and characterised two new photochromic dyes for use in solar cells and we present a study aimed at developing electrolytes specifically adapted to these dyes. Using a methodology based on the design of experiments (DoE) combined with a machine learning (ML) approach, we show that it is possible to quickly find an optimal formulation for iodine-based electrolytes to achieve good transparency of photochromic devices with an AVT ranging from 57% to 23% across the photochromic process, while keeping the photovoltaic conversion efficiency above 2.9%. We show that this approach can be applied to other classes of electrolytes with different redox systems, such as TEMPO/TEMPO+. After optimisation, TEMPO-based electrolytes yielded photochromic semi-transparent solar cells with a PCE of up to 2.16% and an AVT varying between 55% and 13% and opaque photochromic cells with a PCE of 3.46%. Finally, this new TEMPO-based electrolyte was tested with a non-photochromic dye and gave a PCE of up to 7.64%, which is probably the highest performance to date for a dye solar cell using a pure TEMPO/TEMPO+ redox system.
{"title":"Data-driven modelling for electrolyte optimisation in dye-sensitised solar cells and photochromic solar cells.","authors":"Johan Liotier, Antonio J Riquelme, Valid Mwalukuku, Quentin Huaulmé, Yann Kervella, Renaud Demadrille, Cyril Aumaître","doi":"10.1039/d4mh01375a","DOIUrl":"10.1039/d4mh01375a","url":null,"abstract":"<p><p>Because they can be made semi-transparent, dye-sensitised solar cells (DSSCs) have great potential for glazing applications. Their photovoltaic performance and light transmission depend not only on the dye used, but also on the electrolyte they contain. A few years ago, we introduced the concept of solar cells with dynamic optical properties based on the use of photochromic photosensitizers. These cells allow variable light transmission according to sunlight conditions, while producing electrical energy. We found that the electrolytes commonly used in DSSCs are not optimal for this class of photosensitisers and need to be tuned. In this work, we have developed and characterised two new photochromic dyes for use in solar cells and we present a study aimed at developing electrolytes specifically adapted to these dyes. Using a methodology based on the design of experiments (DoE) combined with a machine learning (ML) approach, we show that it is possible to quickly find an optimal formulation for iodine-based electrolytes to achieve good transparency of photochromic devices with an AVT ranging from 57% to 23% across the photochromic process, while keeping the photovoltaic conversion efficiency above 2.9%. We show that this approach can be applied to other classes of electrolytes with different redox systems, such as TEMPO/TEMPO<sup>+</sup>. After optimisation, TEMPO-based electrolytes yielded photochromic semi-transparent solar cells with a PCE of up to 2.16% and an AVT varying between 55% and 13% and opaque photochromic cells with a PCE of 3.46%. Finally, this new TEMPO-based electrolyte was tested with a non-photochromic dye and gave a PCE of up to 7.64%, which is probably the highest performance to date for a dye solar cell using a pure TEMPO/TEMPO<sup>+</sup> redox system.</p>","PeriodicalId":87,"journal":{"name":"Materials Horizons","volume":" ","pages":""},"PeriodicalIF":12.2,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11887455/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143571666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Periodontitis, a chronic inflammatory disease triggered by dental plaque, often presents challenges in management, particularly in severe cases where mechanical debridement alone may be insufficient. As a result, adjunctive therapies, particularly localized drug delivery systems with both antimicrobial and anti-inflammatory properties, are essential to enhance the efficacy of periodontitis management. In this study, we developed a multifunctional hydrogel by incorporating a salicylic acid-choline deep eutectic solvent (DES) into a chitosan/β-glycerol phosphate sodium (CS/GP) hydrogel matrix for the treatment of periodontitis. The DES-CS/GP hydrogel demonstrated favorable physicochemical properties, including gelation and injectability, making it highly suitable for application in the oral cavity. The hydrogel effectively inhibited the growth of key periodontal pathogens, Porphyromonas gingivalis and Fusobacterium nucleatum, and significantly downregulated the expression of pro-inflammatory cytokines TNF-α and IL-1β in vitro. Cytocompatibility assessments showed over 80% cell viability in human gingival fibroblasts, human gingival epithelial cells, and human oral keratinocytes over 5 days treated with DES-CS/GP, with fluorescence microscopy confirming robust cytoskeletal integrity. Furthermore, the hydrogel enhanced permeability through gingival tissues in vitro. In a rat model of periodontitis, the hydrogel significantly mitigated bone loss, reduced bacterial loads of P. g, and suppressed TNF-α and IL-1β expression in gingival tissues. These findings underscore the hydrogel's potential as a safe and effective adjunctive therapy for periodontitis, offering a combination of antimicrobial, anti-inflammatory, and tissue-permeating properties with high biosafety and ease of application.
{"title":"Development of an injectable salicylic acid-choline eutectic hydrogel for enhanced treatment of periodontitis.","authors":"Jin Zhang, Lingzhuang Meng, Yinan Jia, Jianshu Li, Xinyuan Xu, Xin Xu","doi":"10.1039/d4mh01563k","DOIUrl":"https://doi.org/10.1039/d4mh01563k","url":null,"abstract":"<p><p>Periodontitis, a chronic inflammatory disease triggered by dental plaque, often presents challenges in management, particularly in severe cases where mechanical debridement alone may be insufficient. As a result, adjunctive therapies, particularly localized drug delivery systems with both antimicrobial and anti-inflammatory properties, are essential to enhance the efficacy of periodontitis management. In this study, we developed a multifunctional hydrogel by incorporating a salicylic acid-choline deep eutectic solvent (DES) into a chitosan/β-glycerol phosphate sodium (CS/GP) hydrogel matrix for the treatment of periodontitis. The DES-CS/GP hydrogel demonstrated favorable physicochemical properties, including gelation and injectability, making it highly suitable for application in the oral cavity. The hydrogel effectively inhibited the growth of key periodontal pathogens, <i>Porphyromonas gingivalis</i> and <i>Fusobacterium nucleatum</i>, and significantly downregulated the expression of pro-inflammatory cytokines TNF-α and IL-1β <i>in vitro</i>. Cytocompatibility assessments showed over 80% cell viability in human gingival fibroblasts, human gingival epithelial cells, and human oral keratinocytes over 5 days treated with DES-CS/GP, with fluorescence microscopy confirming robust cytoskeletal integrity. Furthermore, the hydrogel enhanced permeability through gingival tissues <i>in vitro.</i> In a rat model of periodontitis, the hydrogel significantly mitigated bone loss, reduced bacterial loads of <i>P. g</i>, and suppressed TNF-α and IL-1β expression in gingival tissues. These findings underscore the hydrogel's potential as a safe and effective adjunctive therapy for periodontitis, offering a combination of antimicrobial, anti-inflammatory, and tissue-permeating properties with high biosafety and ease of application.</p>","PeriodicalId":87,"journal":{"name":"Materials Horizons","volume":" ","pages":""},"PeriodicalIF":12.2,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143571682","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}
Yufu Wang, Vajini Ukwattage, Yijun Xiong, Georgina K Such
Polymeric nanoparticles have emerged as a promising platform for the intracellular delivery of therapeutics, offering unique advantages such as tunable chemical properties and stimuli-responsive behavior. However, a significant challenge in their use remains the efficient delivery of therapeutic cargo to the site of action. This typically relies on escape from endosomal/lysosomal compartments where nanoparticles are trapped upon internalisation within a cell, a process termed endosomal escape. Despite considerable research, the mechanisms underlying endosomal escape are still poorly understood, with inconsistent findings across studies. Moreover, there is a notable lack of standardized methods to accurately quantify this escape process. In this review, we explore the current understanding of endosomal escape mechanisms specific to polymeric nanoparticles and explore critical design strategies that have been used. We also highlight recent advancements in methods to quantify endosomal escape, with the aim of promoting broader application of these technologies in understanding the behaviour of polymeric nanoparticles.
{"title":"Advancing endosomal escape of polymeric nanoparticles: towards improved intracellular delivery.","authors":"Yufu Wang, Vajini Ukwattage, Yijun Xiong, Georgina K Such","doi":"10.1039/d4mh01781a","DOIUrl":"https://doi.org/10.1039/d4mh01781a","url":null,"abstract":"<p><p>Polymeric nanoparticles have emerged as a promising platform for the intracellular delivery of therapeutics, offering unique advantages such as tunable chemical properties and stimuli-responsive behavior. However, a significant challenge in their use remains the efficient delivery of therapeutic cargo to the site of action. This typically relies on escape from endosomal/lysosomal compartments where nanoparticles are trapped upon internalisation within a cell, a process termed endosomal escape. Despite considerable research, the mechanisms underlying endosomal escape are still poorly understood, with inconsistent findings across studies. Moreover, there is a notable lack of standardized methods to accurately quantify this escape process. In this review, we explore the current understanding of endosomal escape mechanisms specific to polymeric nanoparticles and explore critical design strategies that have been used. We also highlight recent advancements in methods to quantify endosomal escape, with the aim of promoting broader application of these technologies in understanding the behaviour of polymeric nanoparticles.</p>","PeriodicalId":87,"journal":{"name":"Materials Horizons","volume":" ","pages":""},"PeriodicalIF":12.2,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143565570","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}
Yujie Peng, Peipei Shao, Ye Yuan, Jingru Mou, Rui-Tao Wen, Hong Chen, Ming Xiao
Traditional thermochromic materials prioritize high sensitivity and rapid discoloration. Reversible thermochromism with delayed discoloration is highly desirable for applications like thermal history indicators and energy-saving windows, yet it has rarely been achieved. Here, we construct such thermochromic composites simply by assembling hydrophobic silica nanoparticles in a polydimethylsiloxane (PDMS) matrix. The films transition from colorless and translucent to blue within minutes when heated above 60 °C and retain their blue color for over eight hours at 20 °C. Remarkably, the discoloration time can be further extended by lowering the environmental relative humidity. Integrating measurements of water absorption, refractive indices, and optical model calculation, we demonstrate that the coloration rises from the combined effects of Rayleigh scattering and multiple scattering and the prolonged discoloration time is surprisingly caused by the gradual absorption of moisture. This unique thermochromic material opens new avenues for advancing thermochromic technology applications.
{"title":"Unravelling the mechanism of coloration and prolonged discoloration in abnormally thermochromic PDMS nanocomposites.","authors":"Yujie Peng, Peipei Shao, Ye Yuan, Jingru Mou, Rui-Tao Wen, Hong Chen, Ming Xiao","doi":"10.1039/d5mh00046g","DOIUrl":"https://doi.org/10.1039/d5mh00046g","url":null,"abstract":"<p><p>Traditional thermochromic materials prioritize high sensitivity and rapid discoloration. Reversible thermochromism with delayed discoloration is highly desirable for applications like thermal history indicators and energy-saving windows, yet it has rarely been achieved. Here, we construct such thermochromic composites simply by assembling hydrophobic silica nanoparticles in a polydimethylsiloxane (PDMS) matrix. The films transition from colorless and translucent to blue within minutes when heated above 60 °C and retain their blue color for over eight hours at 20 °C. Remarkably, the discoloration time can be further extended by lowering the environmental relative humidity. Integrating measurements of water absorption, refractive indices, and optical model calculation, we demonstrate that the coloration rises from the combined effects of Rayleigh scattering and multiple scattering and the prolonged discoloration time is surprisingly caused by the gradual absorption of moisture. This unique thermochromic material opens new avenues for advancing thermochromic technology applications.</p>","PeriodicalId":87,"journal":{"name":"Materials Horizons","volume":" ","pages":""},"PeriodicalIF":12.2,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143565572","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}
Transition metal oxides (TMOs) with perpendicular magnetic anisotropy (PMA) and metallic behavior have promising potential for application in the development of new generation spintronic devices with high density, low power consumption, and nonvolatility. Although much progress has been made, the simultaneous coexistence of robust PMA and excellent metallicity at room temperature or higher temperatures in TMOs remains a huge challenge, limiting their practical application. Herein, high-quality NiCo2O4 (NCO) epitaxial films are reported, which have low resistivity, strong room temperature PMA with highly tunable coercive field, a sign-reversible anomalous Hall effect (AHE), as well as an exchange bias (EB)-like effect. The AHE sign reversal in higher substrate temperature (Tsub.) samples is attributed to the competition between the intrinsic mechanism contributed by the Berry curvature and the extrinsic mechanism dominated by impurity scattering. The EB-like effect in higher Tsub. samples is caused by the presence of non-stoichiometric NCO in films, which in turn leads to local antiferromagnetic coupling. Finally, a perpendicular magnetic tunnel junction based on the NCO homojunction is designed. This work reveals the relevance of cations in NCO to the crystal structure, magnetism and transport properties, which opens up new opportunities for the use of NCO films in the design of novel materials and devices.
{"title":"Revealing the reversal of the anomalous hall effect and the exchange bias-like effect in single-phase perpendicularly magnetized NiCo<sub>2</sub>O<sub>4</sub> epitaxial films.","authors":"Penghua Kang, Guowei Zhou, Jiashuo Liang, Guoxiu Ren, Jiahui Ji, Liying Wang, Chao Jin, Xiaohong Xu","doi":"10.1039/d4mh01764a","DOIUrl":"https://doi.org/10.1039/d4mh01764a","url":null,"abstract":"<p><p>Transition metal oxides (TMOs) with perpendicular magnetic anisotropy (PMA) and metallic behavior have promising potential for application in the development of new generation spintronic devices with high density, low power consumption, and nonvolatility. Although much progress has been made, the simultaneous coexistence of robust PMA and excellent metallicity at room temperature or higher temperatures in TMOs remains a huge challenge, limiting their practical application. Herein, high-quality NiCo<sub>2</sub>O<sub>4</sub> (NCO) epitaxial films are reported, which have low resistivity, strong room temperature PMA with highly tunable coercive field, a sign-reversible anomalous Hall effect (AHE), as well as an exchange bias (EB)-like effect. The AHE sign reversal in higher substrate temperature (<i>T</i><sub>sub.</sub>) samples is attributed to the competition between the intrinsic mechanism contributed by the Berry curvature and the extrinsic mechanism dominated by impurity scattering. The EB-like effect in higher <i>T</i><sub>sub.</sub> samples is caused by the presence of non-stoichiometric NCO in films, which in turn leads to local antiferromagnetic coupling. Finally, a perpendicular magnetic tunnel junction based on the NCO homojunction is designed. This work reveals the relevance of cations in NCO to the crystal structure, magnetism and transport properties, which opens up new opportunities for the use of NCO films in the design of novel materials and devices.</p>","PeriodicalId":87,"journal":{"name":"Materials Horizons","volume":" ","pages":""},"PeriodicalIF":12.2,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143565571","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}
Simultaneously possessing energy conversion properties and reconfigurable anisotropic structures due to their fluidity, semiconducting liquid crystals are an emerging class of soft materials for generating and detecting polarized photons. However, band-gap engineering of liquid crystalline substances remains challenging. Herein, semiconducting liquid crystals exhibiting discotic nematic ordering, linearly polarized monochromatic photoluminescence or broadband white-light emission, and polarization-dependent light-responsiveness (generation of photons and photocurrents) were systematically developed by transforming two-dimensional organic-inorganic metal halide perovskites into mesogenic colloidal nanoparticles. The emission wavelengths of the perovskite liquid crystals could be adjusted with an accuracy of 5 nanometers over a wide range in the visible region by compositional variations, indicating the possibility of fabricating polarized light-emitting or optoelectronic devices with desired band gaps using these materials.
{"title":"Semiconducting liquid crystalline dispersions with precisely adjustable band gaps and polarized photoluminescence.","authors":"Tingting Zhou, Penghao Guo, Xuelian Jiang, Hongbo Zhao, Qing Zhang, Pei-Xi Wang","doi":"10.1039/d4mh01876a","DOIUrl":"https://doi.org/10.1039/d4mh01876a","url":null,"abstract":"<p><p>Simultaneously possessing energy conversion properties and reconfigurable anisotropic structures due to their fluidity, semiconducting liquid crystals are an emerging class of soft materials for generating and detecting polarized photons. However, band-gap engineering of liquid crystalline substances remains challenging. Herein, semiconducting liquid crystals exhibiting discotic nematic ordering, linearly polarized monochromatic photoluminescence or broadband white-light emission, and polarization-dependent light-responsiveness (generation of photons and photocurrents) were systematically developed by transforming two-dimensional organic-inorganic metal halide perovskites into mesogenic colloidal nanoparticles. The emission wavelengths of the perovskite liquid crystals could be adjusted with an accuracy of 5 nanometers over a wide range in the visible region by compositional variations, indicating the possibility of fabricating polarized light-emitting or optoelectronic devices with desired band gaps using these materials.</p>","PeriodicalId":87,"journal":{"name":"Materials Horizons","volume":" ","pages":""},"PeriodicalIF":12.2,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143555402","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}
Photon avalanching (PA) nanomaterials exhibit some of the most nonlinear optical phenomena reported for any material, allowing them to push the frontiers of applications ranging from nanoscale imaging and sensing to optical computing. But PA remains shrouded in mystery, with its underlying physics and limitations misunderstood. Photon avalanching is not, in fact, an avalanche of photons, at least not in the same way that snowballs beget more snowballing in an actual avalanche. In this focus article, we dispel these and other common myths surrounding PA in lanthanide-based nanoparticles and unravel the mysteries of this unique nonlinear optical effect. We hope that removing the misconceptions surrounding avalanching nanoparticles will inspire new interest and applications that harness the giant nonlinearity of PA across a broad range of scientific fields.
{"title":"Unraveling the myths and mysteries of photon avalanching nanoparticles.","authors":"Artiom Skripka, Emory M Chan","doi":"10.1039/d4mh01798f","DOIUrl":"https://doi.org/10.1039/d4mh01798f","url":null,"abstract":"<p><p>Photon avalanching (PA) nanomaterials exhibit some of the most nonlinear optical phenomena reported for any material, allowing them to push the frontiers of applications ranging from nanoscale imaging and sensing to optical computing. But PA remains shrouded in mystery, with its underlying physics and limitations misunderstood. Photon avalanching is not, in fact, an avalanche of photons, at least not in the same way that snowballs beget more snowballing in an actual avalanche. In this focus article, we dispel these and other common myths surrounding PA in lanthanide-based nanoparticles and unravel the mysteries of this unique nonlinear optical effect. We hope that removing the misconceptions surrounding avalanching nanoparticles will inspire new interest and applications that harness the giant nonlinearity of PA across a broad range of scientific fields.</p>","PeriodicalId":87,"journal":{"name":"Materials Horizons","volume":" ","pages":""},"PeriodicalIF":12.2,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143555403","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}