Pub Date : 2024-05-13DOI: 10.1016/j.mtadv.2024.100494
Jaemin Kim, Seungwoo Son, Myeonggi Choe, Zonghoon Lee
With the increasing demand for production of graphitic materials for various applications, it becomes crucial to get a fundamental understanding of how graphene layers grow on metal catalysts. Here, we performed an heating transmission electron microscopy (TEM) study to understand the mechanism of graphitization of amorphous carbon (a-C) on Ni catalyst by following graphene growth at atomic resolution in real time. By discerning the NiC phase from the pure Ni phase during the graphitic carbon growth process, we demonstrate that growth occurs through the carbide graphitization of NiC. Additionally, during the graphitization, Ni diffusion has a crucial effect on the structure of the resulting graphene. Under our experimental conditions, we observed graphene contains islands of multilayers. Based on our experimental results, we suggest a mechanism for graphitization of the a-C/Ni system and explain the dynamics resulting from Ni diffusion. Our study can contribute to the control of graphitization by using Ni catalyst in the production of graphene and other graphitic materials.
随着各种应用领域对石墨材料生产的需求日益增长，从根本上了解石墨烯层如何在金属催化剂上生长变得至关重要。在此，我们进行了一项加热透射电子显微镜（TEM）研究，通过以原子分辨率实时跟踪石墨烯的生长，了解无定形碳（a-C）在镍催化剂上的石墨化机制。通过分辨石墨碳生长过程中的 NiC 相和纯 Ni 相，我们证明了生长是通过 NiC 的碳化物石墨化实现的。此外，在石墨化过程中，镍的扩散对生成的石墨烯的结构有着至关重要的影响。在我们的实验条件下，我们观察到石墨烯含有多层的岛屿。基于我们的实验结果，我们提出了 a-C/Ni 体系的石墨化机制，并解释了镍扩散所产生的动态变化。我们的研究有助于在石墨烯和其他石墨材料的生产中使用镍催化剂来控制石墨化。
{"title":"In situ TEM investigation of nickel catalytic graphitization","authors":"Jaemin Kim, Seungwoo Son, Myeonggi Choe, Zonghoon Lee","doi":"10.1016/j.mtadv.2024.100494","DOIUrl":"https://doi.org/10.1016/j.mtadv.2024.100494","url":null,"abstract":"With the increasing demand for production of graphitic materials for various applications, it becomes crucial to get a fundamental understanding of how graphene layers grow on metal catalysts. Here, we performed an heating transmission electron microscopy (TEM) study to understand the mechanism of graphitization of amorphous carbon (a-C) on Ni catalyst by following graphene growth at atomic resolution in real time. By discerning the NiC phase from the pure Ni phase during the graphitic carbon growth process, we demonstrate that growth occurs through the carbide graphitization of NiC. Additionally, during the graphitization, Ni diffusion has a crucial effect on the structure of the resulting graphene. Under our experimental conditions, we observed graphene contains islands of multilayers. Based on our experimental results, we suggest a mechanism for graphitization of the a-C/Ni system and explain the dynamics resulting from Ni diffusion. Our study can contribute to the control of graphitization by using Ni catalyst in the production of graphene and other graphitic materials.","PeriodicalId":48495,"journal":{"name":"Materials Today Advances","volume":"42 1","pages":""},"PeriodicalIF":10.0,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141063760","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}
In this study, micro-light emitting diodes array (μLEDs) with dimensions of 5 μm and 15 μm chip size were fabricated using Neutral Beam Etching (NBE) processes. Size-dependent issues of μLEDs processed by traditional inductively coupled plasma-reactive ion etching (ICPRIE) were alleviated by NBE technology, which exhibited lower equivalent resistance, turn-on voltage, and Ideality factor as compared with those of μLEDs by ICPRIE. Additionally, higher light output power of μLEDs processed by NBE with both 5 μm and 15 μm resulted in higher EQE 7.6 % and 7.7 % than those of μLEDs processed by ICPRIE. Furthermore, the size effect led to a decrease in EQE values of the ICPRIE sample by 0.4 %, but only a 0.1 % decay in NBE. Overall, samples fabricated by the NBE process exhibited superior optoelectronic characteristics. Finally, non-radiative recombination behaviors on the mesa sidewall were verified by cathodoluminescence analysis, showing significant decay in ICPRIE samples but not in NBE samples. These results demonstrated the potential of the NBE process for fabricating small chip sizes blue-light μLEDs required for high-brightness, high-efficiency, and high-resolution μLED displays.
{"title":"Performance improvement of blue light micro-light emitting diodes (< 20 μm) by neutral beam etching process","authors":"Yu-Hsuan Hsu, Yun-Cheng Hsu, Chien-Chung Lin, Yi-Hsin Lin, Dong-Sing Wuu, Hao-Chung Kuo, Seiji Samukawa, Ray-Hua Horng","doi":"10.1016/j.mtadv.2024.100496","DOIUrl":"https://doi.org/10.1016/j.mtadv.2024.100496","url":null,"abstract":"In this study, micro-light emitting diodes array (μLEDs) with dimensions of 5 μm and 15 μm chip size were fabricated using Neutral Beam Etching (NBE) processes. Size-dependent issues of μLEDs processed by traditional inductively coupled plasma-reactive ion etching (ICPRIE) were alleviated by NBE technology, which exhibited lower equivalent resistance, turn-on voltage, and Ideality factor as compared with those of μLEDs by ICPRIE. Additionally, higher light output power of μLEDs processed by NBE with both 5 μm and 15 μm resulted in higher EQE 7.6 % and 7.7 % than those of μLEDs processed by ICPRIE. Furthermore, the size effect led to a decrease in EQE values of the ICPRIE sample by 0.4 %, but only a 0.1 % decay in NBE. Overall, samples fabricated by the NBE process exhibited superior optoelectronic characteristics. Finally, non-radiative recombination behaviors on the mesa sidewall were verified by cathodoluminescence analysis, showing significant decay in ICPRIE samples but not in NBE samples. These results demonstrated the potential of the NBE process for fabricating small chip sizes blue-light μLEDs required for high-brightness, high-efficiency, and high-resolution μLED displays.","PeriodicalId":48495,"journal":{"name":"Materials Today Advances","volume":"238 1","pages":""},"PeriodicalIF":10.0,"publicationDate":"2024-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141063704","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 : 2024-05-08DOI: 10.1016/j.mtadv.2024.100488
Ali Raza, Jahan Zeb Hassan, Usman Qumar, Ayesha Zaheer, Zaheer Ud Din Babar, Vincenzo Iannotti, Antonio Cassinese
Electrocatalysis utilizing 2D materials is an encouraging approach for advancing sustainable energy conversion technologies. This review explores the strategies employed to achieve robust electrocatalytic activity of 2D materials in key reactions, namely, the OER, HER, and CORR. The distinct structural and electrical characteristics of 2D materials offer opportunities for rapid catalytic performance, indicating significant energy efficiency and selectivity. We systematically discuss the factors governing the electrocatalytic efficiency of two-dimensional materials, including their intrinsic properties, surface modification techniques, heterostructure engineering, and the role of defects. Furthermore, we summarize the recent advances in experimental and theoretical studies to understand the fundamental mechanisms of 2D materials with respect to their catalytic behavior. For the HER, OER, and ORR, defect engineering, phase engineering, interface engineering, and heteroatom doping techniques have been explored. In addition, in the case of the CORR, surface modification, surface-structure tuning, and electrolyte and electrolyzer optimization strategies were examined. This review emphasizes prospective two-dimensional materials as efficient and sustainable electrocatalysts for energy conversion processes. Moreover, it provides future insights into this rapidly evolving field and highlights the possible challenges. In conclusion, it aims to serve as a remarkable resource for researchers seeking to harness the potential response of two-dimensional materials for sustainable energy conversion applications.
{"title":"Strategies for robust electrocatalytic activity of 2D materials: ORR, OER, HER, and CO2RR","authors":"Ali Raza, Jahan Zeb Hassan, Usman Qumar, Ayesha Zaheer, Zaheer Ud Din Babar, Vincenzo Iannotti, Antonio Cassinese","doi":"10.1016/j.mtadv.2024.100488","DOIUrl":"https://doi.org/10.1016/j.mtadv.2024.100488","url":null,"abstract":"Electrocatalysis utilizing 2D materials is an encouraging approach for advancing sustainable energy conversion technologies. This review explores the strategies employed to achieve robust electrocatalytic activity of 2D materials in key reactions, namely, the OER, HER, and CORR. The distinct structural and electrical characteristics of 2D materials offer opportunities for rapid catalytic performance, indicating significant energy efficiency and selectivity. We systematically discuss the factors governing the electrocatalytic efficiency of two-dimensional materials, including their intrinsic properties, surface modification techniques, heterostructure engineering, and the role of defects. Furthermore, we summarize the recent advances in experimental and theoretical studies to understand the fundamental mechanisms of 2D materials with respect to their catalytic behavior. For the HER, OER, and ORR, defect engineering, phase engineering, interface engineering, and heteroatom doping techniques have been explored. In addition, in the case of the CORR, surface modification, surface-structure tuning, and electrolyte and electrolyzer optimization strategies were examined. This review emphasizes prospective two-dimensional materials as efficient and sustainable electrocatalysts for energy conversion processes. Moreover, it provides future insights into this rapidly evolving field and highlights the possible challenges. In conclusion, it aims to serve as a remarkable resource for researchers seeking to harness the potential response of two-dimensional materials for sustainable energy conversion applications.","PeriodicalId":48495,"journal":{"name":"Materials Today Advances","volume":"111 1","pages":""},"PeriodicalIF":10.0,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140934550","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 : 2024-05-03DOI: 10.1016/j.mtadv.2024.100492
Daeyoung Chu, Sanghyun Kang, Gwon Kim, Juho Sung, Jaehyuk Lim, Yejoo Choi, Donghwan Han, Changhwan Shin
Utilizing Ag/HfO with nickel (Ni) as a barrier layer, a novel threshold switching (TS) device is devised to overcome challenges such as low reliability, high threshold voltage, and high leakage current. Compared against an Ag/Ti/HfO-based TS device, the Ag/Ni/HfO-based TS device exhibits improved electrical characteristics: yield enhancement from 31.7 % to 40.0 %, enhanced endurance from ∼10 cycles to ∼300 cycles, and suppression in off-state current (I) from 1.2 × 10 A to 5.2 × 10 A under a high compliance current (e.g., 10 A). The results obtained through transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and atomic force microscopy (AFM) support the evidence of those accomplishments. Reducing the effective area of the TS device improves control over erratically generated filaments and the electric field within the switching layer, resulting in enhanced performance such as a reduced threshold voltage (V ∼0.35 V), minimized V variability (∼0.01 V), decreased a threshold current (I, i.e., the leakage current in the off-state before activation, ∼5.2 × 10 A), and maximum conductance (∼5.0 × 10 S) of low-resistance state. These findings suggest that the optimized Ag/Ni/HfO-based TS device can serve as a practical solution for low-power applications.
{"title":"First integration of Ni barrier layer for enhanced threshold switching characteristics in Ag/HfO2-based TS device","authors":"Daeyoung Chu, Sanghyun Kang, Gwon Kim, Juho Sung, Jaehyuk Lim, Yejoo Choi, Donghwan Han, Changhwan Shin","doi":"10.1016/j.mtadv.2024.100492","DOIUrl":"https://doi.org/10.1016/j.mtadv.2024.100492","url":null,"abstract":"Utilizing Ag/HfO with nickel (Ni) as a barrier layer, a novel threshold switching (TS) device is devised to overcome challenges such as low reliability, high threshold voltage, and high leakage current. Compared against an Ag/Ti/HfO-based TS device, the Ag/Ni/HfO-based TS device exhibits improved electrical characteristics: yield enhancement from 31.7 % to 40.0 %, enhanced endurance from ∼10 cycles to ∼300 cycles, and suppression in off-state current (I) from 1.2 × 10 A to 5.2 × 10 A under a high compliance current (e.g., 10 A). The results obtained through transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and atomic force microscopy (AFM) support the evidence of those accomplishments. Reducing the effective area of the TS device improves control over erratically generated filaments and the electric field within the switching layer, resulting in enhanced performance such as a reduced threshold voltage (V ∼0.35 V), minimized V variability (∼0.01 V), decreased a threshold current (I, i.e., the leakage current in the off-state before activation, ∼5.2 × 10 A), and maximum conductance (∼5.0 × 10 S) of low-resistance state. These findings suggest that the optimized Ag/Ni/HfO-based TS device can serve as a practical solution for low-power applications.","PeriodicalId":48495,"journal":{"name":"Materials Today Advances","volume":"72 1","pages":""},"PeriodicalIF":10.0,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140934634","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 : 2024-05-03DOI: 10.1016/j.mtadv.2024.100491
Chae-Lin Park, Du Won Kim, Sujin Ryu, Joonmyung Choi, Young-Chul Song, Keon Jung Kim, Sang Won Lee, Seongjae Oh, Doyoung Kim, Young Hwan Bae, Hyun Kim, Seon-Jin Choi, Jaehoon Ko, Shi Hyeong Kim, Hyunsoo Kim
Carbon-based fibers have attracted attention in various field owing to their exceptional properties, including high tensile strength, thermal stability, and electrical conductivity. In particular, graphene-based high-strength fibers are promising materials in aerospace, automotive, and marine sectors. Recently, the hybrid fiber, consisting of carbon nanotubes (CNTs) and graphene with enhanced toughness was reported by deflecting cracks and enabling high deformation. However, complex synthesis and structural optimization of composite fiber with two different materials make challenge for mass production. Here, we introduce a novel graphene composite fiber, consisting of reduced graphene oxide (rGO) and scrolled rGO (SrGO), showing remarkable toughness. A multidimensional-state solution with 2D rGO and 1D SrGO was obtained by using a simple sonication technique. Mass production of high-toughness composite fibers was achieved via wet-spinning, with enhanced toughness attributed to microstructure optimization by controlling the SrGO ratio. Additionally, the use of poly(vinyl alcohol) (PVA) as the matrix facilitated high deformation, resulting in a remarkable 90.7 % increase in mechanical toughness without complex composite material synthesis.
{"title":"Wet-spinning of reduced graphene oxide composite fiber by mechanical synergistic effect with graphene scrolling method","authors":"Chae-Lin Park, Du Won Kim, Sujin Ryu, Joonmyung Choi, Young-Chul Song, Keon Jung Kim, Sang Won Lee, Seongjae Oh, Doyoung Kim, Young Hwan Bae, Hyun Kim, Seon-Jin Choi, Jaehoon Ko, Shi Hyeong Kim, Hyunsoo Kim","doi":"10.1016/j.mtadv.2024.100491","DOIUrl":"https://doi.org/10.1016/j.mtadv.2024.100491","url":null,"abstract":"Carbon-based fibers have attracted attention in various field owing to their exceptional properties, including high tensile strength, thermal stability, and electrical conductivity. In particular, graphene-based high-strength fibers are promising materials in aerospace, automotive, and marine sectors. Recently, the hybrid fiber, consisting of carbon nanotubes (CNTs) and graphene with enhanced toughness was reported by deflecting cracks and enabling high deformation. However, complex synthesis and structural optimization of composite fiber with two different materials make challenge for mass production. Here, we introduce a novel graphene composite fiber, consisting of reduced graphene oxide (rGO) and scrolled rGO (SrGO), showing remarkable toughness. A multidimensional-state solution with 2D rGO and 1D SrGO was obtained by using a simple sonication technique. Mass production of high-toughness composite fibers was achieved via wet-spinning, with enhanced toughness attributed to microstructure optimization by controlling the SrGO ratio. Additionally, the use of poly(vinyl alcohol) (PVA) as the matrix facilitated high deformation, resulting in a remarkable 90.7 % increase in mechanical toughness without complex composite material synthesis.","PeriodicalId":48495,"journal":{"name":"Materials Today Advances","volume":"32 1","pages":""},"PeriodicalIF":10.0,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140934632","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 : 2024-04-17DOI: 10.1016/j.mtadv.2024.100489
T.U. Schülli, E Dollekamp, Z Ismaili, N. Nawaz, T. Januel, T. Billo, P. Brumund, H. Djazouli, S.J. Leake, M. Jankowski, V. Reita, M. Rodriguez, L. André, A. Aliane, Y.M. Le Vaillant
Imposing and controlling strain in materials such as semiconductors or ferroelectrics is a promising way to obtain new or enhance existing properties. Although the field of strain engineering has seen a rapid expansion over the last two decades, straining semiconductor membranes over large areas remains a challenge. A generic way of tuning strain and hence band structure and electric or magnetic properties of any crystalline material can be obtained by compression of a composite structure involving poorly compressible elastomers. Mechanically similar to the principle of a hydraulic press, this work proposes a device and describes analytically a methodology to easily strain macroscopic membranes up to unprecedented values. Using X-ray diffraction and Raman spectroscopy, we tuned the biaxial strain in silicon membranes up to a value of 2.1 %, paving the way for new studies in the field of strain related physics, from semiconductors to perovskite oxide multiferroics.
在半导体或铁电体等材料中施加和控制应变是获得新特性或增强现有特性的一种很有前途的方法。虽然应变工程领域在过去二十年中迅速发展，但大面积应变半导体膜仍然是一项挑战。通过压缩涉及可压缩性差的弹性体的复合结构，可以获得调整应变的通用方法，进而调整任何晶体材料的带状结构和电或磁特性。与液压机的原理类似，这项研究提出了一种装置，并通过分析描述了一种方法，可以轻松地将宏观膜的应变值提高到前所未有的水平。利用 X 射线衍射和拉曼光谱，我们将硅膜中的双轴应变调整到了 2.1 % 的值，为应变相关物理学领域的新研究铺平了道路，包括从半导体到过氧化物多铁氧体。
{"title":"Dynamic and controlled stretching of macroscopic crystalline membranes towards unprecedented levels","authors":"T.U. Schülli, E Dollekamp, Z Ismaili, N. Nawaz, T. Januel, T. Billo, P. Brumund, H. Djazouli, S.J. Leake, M. Jankowski, V. Reita, M. Rodriguez, L. André, A. Aliane, Y.M. Le Vaillant","doi":"10.1016/j.mtadv.2024.100489","DOIUrl":"https://doi.org/10.1016/j.mtadv.2024.100489","url":null,"abstract":"Imposing and controlling strain in materials such as semiconductors or ferroelectrics is a promising way to obtain new or enhance existing properties. Although the field of strain engineering has seen a rapid expansion over the last two decades, straining semiconductor membranes over large areas remains a challenge. A generic way of tuning strain and hence band structure and electric or magnetic properties of any crystalline material can be obtained by compression of a composite structure involving poorly compressible elastomers. Mechanically similar to the principle of a hydraulic press, this work proposes a device and describes analytically a methodology to easily strain macroscopic membranes up to unprecedented values. Using X-ray diffraction and Raman spectroscopy, we tuned the biaxial strain in silicon membranes up to a value of 2.1 %, paving the way for new studies in the field of strain related physics, from semiconductors to perovskite oxide multiferroics.","PeriodicalId":48495,"journal":{"name":"Materials Today Advances","volume":"47 1","pages":""},"PeriodicalIF":10.0,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140804693","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 : 2024-04-17DOI: 10.1016/j.mtadv.2024.100486
Qingyang Fan, Heng Liu, Chongdan Ren, Sining Yun, Udo Schwingenschlögl
284 carbon allotropes with space group (No. 53) are proposed based on high-throughput calculations and density functional theory. Out of 14,285 initially identified candidates, 284 carbon allotropes are confirmed by structure optimization, removal of repetitive structures, calculation of relative enthalpies, and verification of the mechanical and thermal stabilities. Among them, 135 are metals, 55 are direct band gap semiconductors (in 15 cases with a band gap between 1.0 and 1.5 eV), 46 have three-dimensional conductive channels, 32 are superhard, and 3 are type-I Dirac semimetals.
{"title":"High-throughput design of three-dimensional carbon allotropes with Pmna space group","authors":"Qingyang Fan, Heng Liu, Chongdan Ren, Sining Yun, Udo Schwingenschlögl","doi":"10.1016/j.mtadv.2024.100486","DOIUrl":"https://doi.org/10.1016/j.mtadv.2024.100486","url":null,"abstract":"284 carbon allotropes with space group (No. 53) are proposed based on high-throughput calculations and density functional theory. Out of 14,285 initially identified candidates, 284 carbon allotropes are confirmed by structure optimization, removal of repetitive structures, calculation of relative enthalpies, and verification of the mechanical and thermal stabilities. Among them, 135 are metals, 55 are direct band gap semiconductors (in 15 cases with a band gap between 1.0 and 1.5 eV), 46 have three-dimensional conductive channels, 32 are superhard, and 3 are type-I Dirac semimetals.","PeriodicalId":48495,"journal":{"name":"Materials Today Advances","volume":"52 1","pages":""},"PeriodicalIF":10.0,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140615336","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}
Cobalt-based amorphous alloys (Co-MG) demonstrate ultra-high permeability and remarkably-low power loss, positioning them as promising candidates for shielding (near-) static magnetic fields and addressing accuracy limitations in extremely-weak magnetic measurements. , the brittleness and poor understanding about magnetic performance below 100 Hz have impeded their widespread adoption. To integrate satisfied processing, magnetic and mechanical performances, polystyrene-grafted Co-MG composites are developed. Compared with permalloy-1J85, Co-MG-(-PS_35 %) composite exhibits 40 % increase in initial permeability, 48 % increase in saturation magnetization, 71 % reduction in remanence within shielding area. In contrast to Mn–Zn ferrite, Co-MG-(-PS_35 %) composite demonstrates the power loss and ″/′ values lower by an order of magnitude, resulting in magnetic noises 85 % lower at 1 Hz. Furthermore, the resultant composite maintains similar processing-rheological behaviors and mechanical properties compared with bulk polystyrene. It provides an innovative solution to expand real-world applications for biomagnetic detection, and overcome the sensitivity limitation of extremely-weak magnetic measurement.
{"title":"Low magnetic noise, easy-to-process polystyrene-grafted amorphous alloy composites for extremely-weak magnetic measurement at ultra-low frequency","authors":"Ting Sai, Pengfei Wang, Xiaoying Gu, Xueping Xu, Jinji Sun, Jing Ye","doi":"10.1016/j.mtadv.2024.100487","DOIUrl":"https://doi.org/10.1016/j.mtadv.2024.100487","url":null,"abstract":"Cobalt-based amorphous alloys (Co-MG) demonstrate ultra-high permeability and remarkably-low power loss, positioning them as promising candidates for shielding (near-) static magnetic fields and addressing accuracy limitations in extremely-weak magnetic measurements. , the brittleness and poor understanding about magnetic performance below 100 Hz have impeded their widespread adoption. To integrate satisfied processing, magnetic and mechanical performances, polystyrene-grafted Co-MG composites are developed. Compared with permalloy-1J85, Co-MG-(-PS_35 %) composite exhibits 40 % increase in initial permeability, 48 % increase in saturation magnetization, 71 % reduction in remanence within shielding area. In contrast to Mn–Zn ferrite, Co-MG-(-PS_35 %) composite demonstrates the power loss and ″/′ values lower by an order of magnitude, resulting in magnetic noises 85 % lower at 1 Hz. Furthermore, the resultant composite maintains similar processing-rheological behaviors and mechanical properties compared with bulk polystyrene. It provides an innovative solution to expand real-world applications for biomagnetic detection, and overcome the sensitivity limitation of extremely-weak magnetic measurement.","PeriodicalId":48495,"journal":{"name":"Materials Today Advances","volume":"305 1","pages":""},"PeriodicalIF":10.0,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140615312","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 : 2024-04-10DOI: 10.1016/j.mtadv.2024.100490
Xinyu Lu, Yi Luo, Xiaochun Hu, Jianjian Chu, Siqi Li, Mengqi Hao, Jianhua Zhuang, Yan Liu, Jie Gao, You Yin
Brain diseases, encompassing neurodegenerative disorders, strokes, and brain tumors, represent significant medical conditions with profound implications for human health. The blood-brain barrier (BBB) and the blood-cerebral-spinal cord barrier (BCSFB) limited drug penetration, poor drug targeting, and limited proliferation and easy death of mature neuronal cells greatly impair regeneration of the central nervous system after the injury, and thus call for more advanced therapeutic strategies in the clinic. Biomedical hydrogel research presents a potentially novel therapeutic approach for the management of brain disorders. Hydrogels are extremely biocompatible scaffolding materials that can be loaded with a variety of drugs for achieving effective treatments for brain disorders and can be customized with different mechanical properties to match the target organ or modulate its environment. This article offers an overview of recent research progress, challenges, and prospective developments in the utilization of hydrogels for treating brain disorders, with the objective of accentuating their potential as an early intervention in the preclinical phase. The unique mechanisms of drug release in hydrogels are examined in detail: extended-release medications, environmental release of drugs, and the material's own activity. An understanding of these mechanisms helps to make more effective drug delivery systems to the brain possible.
{"title":"Emerging hydrogel therapies for translating brain disease: Materials, mechanisms, and recent research","authors":"Xinyu Lu, Yi Luo, Xiaochun Hu, Jianjian Chu, Siqi Li, Mengqi Hao, Jianhua Zhuang, Yan Liu, Jie Gao, You Yin","doi":"10.1016/j.mtadv.2024.100490","DOIUrl":"https://doi.org/10.1016/j.mtadv.2024.100490","url":null,"abstract":"Brain diseases, encompassing neurodegenerative disorders, strokes, and brain tumors, represent significant medical conditions with profound implications for human health. The blood-brain barrier (BBB) and the blood-cerebral-spinal cord barrier (BCSFB) limited drug penetration, poor drug targeting, and limited proliferation and easy death of mature neuronal cells greatly impair regeneration of the central nervous system after the injury, and thus call for more advanced therapeutic strategies in the clinic. Biomedical hydrogel research presents a potentially novel therapeutic approach for the management of brain disorders. Hydrogels are extremely biocompatible scaffolding materials that can be loaded with a variety of drugs for achieving effective treatments for brain disorders and can be customized with different mechanical properties to match the target organ or modulate its environment. This article offers an overview of recent research progress, challenges, and prospective developments in the utilization of hydrogels for treating brain disorders, with the objective of accentuating their potential as an early intervention in the preclinical phase. The unique mechanisms of drug release in hydrogels are examined in detail: extended-release medications, environmental release of drugs, and the material's own activity. An understanding of these mechanisms helps to make more effective drug delivery systems to the brain possible.","PeriodicalId":48495,"journal":{"name":"Materials Today Advances","volume":"211 1","pages":""},"PeriodicalIF":10.0,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140572067","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 fabrication of InGaN-based blue 4✕4 array micro-LEDs (μLEDs) with 40 μm ✕40 μm chip size and 2✕2 array μLEDs with 80 μm ✕80 μm chip size etching by the inductive coupled plasma reactive ion etching (ICPRIE) and defect-free neutral beam etching (NBE) processes was studied in this work. In μLEDs of this size, the influence of defects formation in the sidewalls on EQE was evaluated. There was almost no difference in EQE between μLEDs array etched by the NBE process no matter 40 μm ✕40 μm and 80 μm ✕80 μm, but the dependence was observed in the ICPRIE. Even with this size, it was found that the size effect of EQE is smaller than that in case of using ICPRIE for defect-free neutral beam etching. This impact is substantial since μLED predominantly operated at low current density, around 1–5 A/cm. Consequently, the reduction of defect density, encompassing both internal and sidewall defects, becomes imperative even in 40–80 μm InGaN-based μLEDs. This not only improves the overall efficiency of μLEDs but also fortifies the brightness stability of μLED displays if process etching by NBE. It was also found that the etching shape had an influence on EQE. It could be attributed to fact that the etching profile angle of NBE was more vertical than that of ICPRIE. Because the different angles of the mesa resulted in different light intensity. The μLEDs emitting with a wavelength of 450 nm, the light extraction efficiency and intensity at a mesa angle 58° of NBE etching μLEDs was about 8% lower than those of an angle (38°) of ICPRIE etching μLEDs by simulation.
{"title":"Performance comparison of InGaN-based 40–80 μm micro-LEDs fabricated with and without plasma etching","authors":"Yu-Yun Lo, Yi-Ho Chen, Yun-Cheng Hsu, Tzu-Yi Lee, Yu-Ying Hung, Yu-Cheng Kao, Hsiao-Wen Zan, Dong- Sing Wuu, Hao-Chung Kuo, Seiji Samukawa, Ray-Hua Horng","doi":"10.1016/j.mtadv.2024.100485","DOIUrl":"https://doi.org/10.1016/j.mtadv.2024.100485","url":null,"abstract":"The fabrication of InGaN-based blue 4✕4 array micro-LEDs (μLEDs) with 40 μm ✕40 μm chip size and 2✕2 array μLEDs with 80 μm ✕80 μm chip size etching by the inductive coupled plasma reactive ion etching (ICPRIE) and defect-free neutral beam etching (NBE) processes was studied in this work. In μLEDs of this size, the influence of defects formation in the sidewalls on EQE was evaluated. There was almost no difference in EQE between μLEDs array etched by the NBE process no matter 40 μm ✕40 μm and 80 μm ✕80 μm, but the dependence was observed in the ICPRIE. Even with this size, it was found that the size effect of EQE is smaller than that in case of using ICPRIE for defect-free neutral beam etching. This impact is substantial since μLED predominantly operated at low current density, around 1–5 A/cm. Consequently, the reduction of defect density, encompassing both internal and sidewall defects, becomes imperative even in 40–80 μm InGaN-based μLEDs. This not only improves the overall efficiency of μLEDs but also fortifies the brightness stability of μLED displays if process etching by NBE. It was also found that the etching shape had an influence on EQE. It could be attributed to fact that the etching profile angle of NBE was more vertical than that of ICPRIE. Because the different angles of the mesa resulted in different light intensity. The μLEDs emitting with a wavelength of 450 nm, the light extraction efficiency and intensity at a mesa angle 58° of NBE etching μLEDs was about 8% lower than those of an angle (38°) of ICPRIE etching μLEDs by simulation.","PeriodicalId":48495,"journal":{"name":"Materials Today Advances","volume":"120 1","pages":""},"PeriodicalIF":10.0,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140572072","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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