Pub Date : 2024-10-24DOI: 10.1016/j.jsamd.2024.100797
Beste Dipcin , Bora Guvendiren , Selcuk Birdogan , Bukem Tanoren
Carbon quantum dots (CQDs) are carbon-based biocompatible quantum dots that have low toxicity, are more soluble in water, have broad application areas, and the surface modification of these can be performed easily. In this study, we present a new CQD synthesis method with cost-effective reactants that can be easily found in laboratories are used. Besides, there is a definitive indication (bubble) for CQD production, unlike the other methods in the literature. The purification method of the CQDs was also optimized in this study. In the beginning of the synthesis, 3 times centrifugation (x3 CF) of the mixture was performed and the optimization of the purification method indicated that x3 CF before 3 days of dialysis membrane tubing (x3 CF & 3 DM) resulted in the formation of the purest CQDs. The characterization of the CQDs was done utilizing UV–VIS spectrophotometer, Fourier Transfer Infrared Spectroscopy (FT-IR), Zetasizer, fluorescence microscopy, Dynamic Light Scattering (DLS), Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS), and Transmission Electron Microscopy (TEM). It was concluded that the CQD formation depended on the mixing of sulphuric acid:acetone (2:1) ratio in a hot (140–165 °C) and an inert environment, and bubble coverage of the mixture surface (30–60 s). The bubble formation due to the reaction between sulphuric acid and pure acetone at high temperatures gives the developed method’s name of “Hot Bubble Synthesis” (HBBBS).
{"title":"A novel carbon quantum dot (CQD) synthesis method with cost-effective reactants and a definitive indication: Hot bubble synthesis (HBBBS)","authors":"Beste Dipcin , Bora Guvendiren , Selcuk Birdogan , Bukem Tanoren","doi":"10.1016/j.jsamd.2024.100797","DOIUrl":"10.1016/j.jsamd.2024.100797","url":null,"abstract":"<div><div>Carbon quantum dots (CQDs) are carbon-based biocompatible quantum dots that have low toxicity, are more soluble in water, have broad application areas, and the surface modification of these can be performed easily. In this study, we present a new CQD synthesis method with cost-effective reactants that can be easily found in laboratories are used. Besides, there is a definitive indication (bubble) for CQD production, unlike the other methods in the literature. The purification method of the CQDs was also optimized in this study. In the beginning of the synthesis, 3 times centrifugation (x3 CF) of the mixture was performed and the optimization of the purification method indicated that x3 CF before 3 days of dialysis membrane tubing (x3 CF & 3 DM) resulted in the formation of the purest CQDs. The characterization of the CQDs was done utilizing UV–VIS spectrophotometer, Fourier Transfer Infrared Spectroscopy (FT-IR), Zetasizer, fluorescence microscopy, Dynamic Light Scattering (DLS), Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS), and Transmission Electron Microscopy (TEM). It was concluded that the CQD formation depended on the mixing of sulphuric acid:acetone (2:1) ratio in a hot (140–165 °C) and an inert environment, and bubble coverage of the mixture surface (30–60 s). The bubble formation due to the reaction between sulphuric acid and pure acetone at high temperatures gives the developed method’s name of “Hot Bubble Synthesis” (HBBBS).</div></div>","PeriodicalId":17219,"journal":{"name":"Journal of Science: Advanced Materials and Devices","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-24DOI: 10.1016/j.jsamd.2024.100805
Fandi Jean , Muhammad Umair Khan , Anas Alazzam , Baker Mohammad
As a sustainable energy source, sound is abundant in the environment, but its effective conversion into electrical energy remains a technical challenge. Triboelectric nanogenerators (TENGs) have made significant progress in addressing this issue, enabling the efficient capture of low-frequency sound waves and their transformation into usable power. This review explores the core principles behind acoustic energy harvesting using TENGs and examines key advancements in materials and resonator designs, including Helmholtz and quarter-wavelength configurations, which enhance energy conversion. Recent breakthroughs in TENG technologies are also highlighted, focusing on specialized mechanisms and innovative structural designs that improve sound wave collection and energy transfer. The review also looks into the various applications of TENGs, including harnessing urban noise, enhancing voice recognition systems, and powering wearable devices. Finally, challenges and future directions for expanding the use of acoustic energy harvesting technologies are discussed,focusing on their potential to provide practical and scalable energy solutions for various applications.
作为一种可持续能源，声音在环境中含量丰富，但将其有效转化为电能仍是一项技术挑战。三电纳米发电机（TENGs）在解决这一问题方面取得了重大进展，能够有效捕捉低频声波并将其转化为可用电能。这篇综述探讨了使用 TENGs 收集声能背后的核心原理，并研究了材料和谐振器设计方面的主要进展，包括能增强能量转换的赫尔姆霍兹和四分之一波长配置。此外，还重点介绍了最近在 TENG 技术方面取得的突破，重点关注可改善声波收集和能量传递的专门机制和创新结构设计。综述还探讨了 TENG 的各种应用，包括利用城市噪音、增强语音识别系统和为可穿戴设备供电。最后，还讨论了扩大声能收集技术应用的挑战和未来方向，重点关注其为各种应用提供实用、可扩展的能源解决方案的潜力。
{"title":"Harnessing ambient sound: Different approaches to acoustic energy harvesting using triboelectric nanogenerators","authors":"Fandi Jean , Muhammad Umair Khan , Anas Alazzam , Baker Mohammad","doi":"10.1016/j.jsamd.2024.100805","DOIUrl":"10.1016/j.jsamd.2024.100805","url":null,"abstract":"<div><div>As a sustainable energy source, sound is abundant in the environment, but its effective conversion into electrical energy remains a technical challenge. Triboelectric nanogenerators (TENGs) have made significant progress in addressing this issue, enabling the efficient capture of low-frequency sound waves and their transformation into usable power. This review explores the core principles behind acoustic energy harvesting using TENGs and examines key advancements in materials and resonator designs, including Helmholtz and quarter-wavelength configurations, which enhance energy conversion. Recent breakthroughs in TENG technologies are also highlighted, focusing on specialized mechanisms and innovative structural designs that improve sound wave collection and energy transfer. The review also looks into the various applications of TENGs, including harnessing urban noise, enhancing voice recognition systems, and powering wearable devices. Finally, challenges and future directions for expanding the use of acoustic energy harvesting technologies are discussed,focusing on their potential to provide practical and scalable energy solutions for various applications.</div></div>","PeriodicalId":17219,"journal":{"name":"Journal of Science: Advanced Materials and Devices","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-19DOI: 10.1016/j.jsamd.2024.100798
Shonak Bansal , Abha Kiran Rajpoot , G. Chamundeswari , Krishna Prakash , Parvataneni Rajendra Kumar , Ahmed Nabih Zaki Rashed , Mohamed S. Soliman , Mohammad Tariqul Islam
The search for highly efficient photodetectors, driven by various applications ranging from environmental monitoring to communication systems and imaging, continues to drive research into novel materials and innovative device architectures. This paper offers an in-depth comparative analysis to optimize the performance of two types of Schottky ultraviolet (UV) photodetectors: platinum (Pt)/zinc oxide (ZnO) and Pt/few-layer graphene (FLG)/ZnO, both featuring aluminum (Al) ohmic contacts. The study systematically examines and compares the electrical and optical characteristics of these two photodetector configurations using the Silvaco TCAD simulation tool and machine learning regression models. The research outcomes demonstrate that the proposed photodetector configurations exhibit remarkable improvements, showcasing their substantial potential for superior performance in UV applications. The Pt/ZnO photodetector demonstrates a dark current density of 8.2 × 10−11 pA/cm2, a photocurrent density of 0.26 μA/cm2, a 3-dB cut-off frequency of 85.4 GHz, an external quantum efficiency of 90.41%, and an external photocurrent responsivity of 0.26A/W, at a bias of −1.0 V. On the other hand, Pt/FLG/ZnO photodetector demonstrates near zero dark current density, a photocurrent density of 0.2 μA/cm2, a 3-dB cut-off frequency of 2.44 THz, an external quantum efficiency of 68.52%, and an external photocurrent responsivity of 0.2 A/W at a bias of −1.0 V. Furthermore, a comprehensive comparative analysis of various machine-learning regression models is conducted, validating the simulation findings and providing a predictive framework for optimizing the photodetector's performance. Each machine-learning regression model is evaluated by getting root mean squared error and R2 values across different test set sizes to assess their accuracy in predicting the photodetector's characteristics. This study underscores the promising role of cutting-edge materials and computational techniques in advancing the development of next-generation optoelectronic devices with enhanced capabilities and performance.
{"title":"Pt/ZnO and Pt/few-layer graphene/ZnO Schottky devices with Al ohmic contacts using Atlas simulation and machine learning","authors":"Shonak Bansal , Abha Kiran Rajpoot , G. Chamundeswari , Krishna Prakash , Parvataneni Rajendra Kumar , Ahmed Nabih Zaki Rashed , Mohamed S. Soliman , Mohammad Tariqul Islam","doi":"10.1016/j.jsamd.2024.100798","DOIUrl":"10.1016/j.jsamd.2024.100798","url":null,"abstract":"<div><div>The search for highly efficient photodetectors, driven by various applications ranging from environmental monitoring to communication systems and imaging, continues to drive research into novel materials and innovative device architectures. This paper offers an in-depth comparative analysis to optimize the performance of two types of Schottky ultraviolet (UV) photodetectors: platinum (Pt)/zinc oxide (ZnO) and Pt/few-layer graphene (FLG)/ZnO, both featuring aluminum (Al) ohmic contacts. The study systematically examines and compares the electrical and optical characteristics of these two photodetector configurations using the Silvaco TCAD simulation tool and machine learning regression models. The research outcomes demonstrate that the proposed photodetector configurations exhibit remarkable improvements, showcasing their substantial potential for superior performance in UV applications. The Pt/ZnO photodetector demonstrates a dark current density of 8.2 × 10<sup>−11</sup> pA/cm<sup>2</sup>, a photocurrent density of 0.26 μA/cm<sup>2</sup>, a 3-dB cut-off frequency of 85.4 GHz, an external quantum efficiency of 90.41%, and an external photocurrent responsivity of 0.26A/W, at a bias of −1.0 V. On the other hand, Pt/FLG/ZnO photodetector demonstrates near zero dark current density, a photocurrent density of 0.2 μA/cm<sup>2</sup>, a 3-dB cut-off frequency of 2.44 THz, an external quantum efficiency of 68.52%, and an external photocurrent responsivity of 0.2 A/W at a bias of −1.0 V. Furthermore, a comprehensive comparative analysis of various machine-learning regression models is conducted, validating the simulation findings and providing a predictive framework for optimizing the photodetector's performance. Each machine-learning regression model is evaluated by getting root mean squared error and <em>R</em><sup>2</sup> values across different test set sizes to assess their accuracy in predicting the photodetector's characteristics. This study underscores the promising role of cutting-edge materials and computational techniques in advancing the development of next-generation optoelectronic devices with enhanced capabilities and performance.</div></div>","PeriodicalId":17219,"journal":{"name":"Journal of Science: Advanced Materials and Devices","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-18DOI: 10.1016/j.jsamd.2024.100799
Ismail M. Tayel, Mogtaba Mohammed
The purpose of this research is to introduce a new model for studying the photothermal process in a 2D semiconducting material with temperature-dependent properties using the recently modified Green and Lindsay theory. The surface absorption fashion generated by a laser pulse is used to heat a medium whose surface is subjected to cooling impact and considered traction free. The integral transformation method is used to attain a general solution via Fourier and Laplace transforms, and the inverse Laplace transform is performed numerically using Riemann sum approximation. A silicon element is utilized to get findings that are graphically displayed as an application in which the consistency of outcomes may be deduced.
{"title":"Photothermal impacts induced by laser pulse in a 2D semiconducting medium with temperature-dependent properties under strain–temperature rate-dependent theory","authors":"Ismail M. Tayel, Mogtaba Mohammed","doi":"10.1016/j.jsamd.2024.100799","DOIUrl":"10.1016/j.jsamd.2024.100799","url":null,"abstract":"<div><div>The purpose of this research is to introduce a new model for studying the photothermal process in a 2D semiconducting material with temperature-dependent properties using the recently modified Green and Lindsay theory. The surface absorption fashion generated by a laser pulse is used to heat a medium whose surface is subjected to cooling impact and considered traction free. The integral transformation method is used to attain a general solution via Fourier and Laplace transforms, and the inverse Laplace transform is performed numerically using Riemann sum approximation. A silicon element is utilized to get findings that are graphically displayed as an application in which the consistency of outcomes may be deduced.</div></div>","PeriodicalId":17219,"journal":{"name":"Journal of Science: Advanced Materials and Devices","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-18DOI: 10.1016/j.jsamd.2024.100804
Laimis Zubauskas, Edgaras Markauskas, Arnas Vyšniauskas, Valdemar Stankevič, Paulius Gečys
The growing demand for flexible, high-quality fabrication of free-form micro-optics drives the development of laser-based fabrication techniques for both the shape formation and surface polishing of optical elements. In this paper, we performed a thorough and systematic study on fused silica glass ablation using 10 ps and 320 fs duration pulses. Ablation processes for both pulse durations were optimized based on the measurements of the removed material layer thickness and surface roughness, and by analyzing the topographies of ablated cavities to remove material layers as thin as possible with minimum surface damage. Our findings demonstrate higher process resolution and surface quality for femtosecond pulses. Ablation of pre-roughened glass reduced the minimal removable glass layer thickness well below the 1 μm mark for both pulse durations, improving the process resolution. The minimal removable glass layer thickness was 14 times smaller for the femtosecond pulses, with up to 4.5 times lower surface roughness compared to samples processed with picosecond pulses. On the other hand, results revealed faster glass removal rates with picosecond pulses. In the end, arrays of microlenses were fabricated with both pulse durations and subsequently polished with a CO2 laser. Results revealed higher performance of microlenses fabricated with femtosecond pulses, providing better focusing capabilities and lesser beam scattering. Finally, this study demonstrated the successful fabrication of free-form optical elements with femtosecond and picosecond pulses, demonstrating the versatility and the potential of laser-based techniques.
{"title":"Comparative analysis of microlens array formation in fused silica glass by laser: Femtosecond versus picosecond pulses","authors":"Laimis Zubauskas, Edgaras Markauskas, Arnas Vyšniauskas, Valdemar Stankevič, Paulius Gečys","doi":"10.1016/j.jsamd.2024.100804","DOIUrl":"10.1016/j.jsamd.2024.100804","url":null,"abstract":"<div><div>The growing demand for flexible, high-quality fabrication of free-form micro-optics drives the development of laser-based fabrication techniques for both the shape formation and surface polishing of optical elements. In this paper, we performed a thorough and systematic study on fused silica glass ablation using 10 ps and 320 fs duration pulses. Ablation processes for both pulse durations were optimized based on the measurements of the removed material layer thickness and surface roughness, and by analyzing the topographies of ablated cavities to remove material layers as thin as possible with minimum surface damage. Our findings demonstrate higher process resolution and surface quality for femtosecond pulses. Ablation of pre-roughened glass reduced the minimal removable glass layer thickness well below the 1 μm mark for both pulse durations, improving the process resolution. The minimal removable glass layer thickness was 14 times smaller for the femtosecond pulses, with up to 4.5 times lower surface roughness compared to samples processed with picosecond pulses. On the other hand, results revealed faster glass removal rates with picosecond pulses. In the end, arrays of microlenses were fabricated with both pulse durations and subsequently polished with a CO<sub>2</sub> laser. Results revealed higher performance of microlenses fabricated with femtosecond pulses, providing better focusing capabilities and lesser beam scattering. Finally, this study demonstrated the successful fabrication of free-form optical elements with femtosecond and picosecond pulses, demonstrating the versatility and the potential of laser-based techniques.</div></div>","PeriodicalId":17219,"journal":{"name":"Journal of Science: Advanced Materials and Devices","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-11DOI: 10.1016/j.jsamd.2024.100795
B. Mounika , J. Ajayan , Sandip Bhattacharya , D. Nirmal , Amit Krishna Dwivedi
High-performance LG = 50 nm graded double-channel (GDC)-HEMT featuring AlN top barrier, recessed T-gate and graded-AlGaN bottom barrier is designed and investigated. Two quantum wells are formed in the AlN-GaN-graded AlGaN-GaN multilayer structure developed on a SiC substrate and the clear double hump feature of the transconductance (GM), cut-off frequency (fT), and capacitance plots clearly illustrates the double-channel (DC) behavior. The investigations carried out to explore the impact of barrier thickness (both AlN & graded-AlGaN) revealed superior performance with the GM showing two peaks at 181.5 & 488.1 mS/mm, the peak-drive-current (ID_peak) with VGS biased at 3 V is 1.81 A/mm, maximum saturation drain current of 3.08 A/mm (VGS = 3V), and the fT derived from the left- and right-hump are 263.7 GHz & 354.2 GHz, respectively, when both barriers are 6 nm thin, attributable to enhanced 2DEG density due to the coordination of channels because of proximity and lower leakage. It has been noticed that when the bottom barrier is thick, the DC behaviour is less obvious due to insufficient gate access to the lower channel. We investigated the impact of varying the Al % in AlGaN top barrier on the DC/RF performance of GDC-HEMTs, demonstrating enhanced performance with increased Al content, particularly for Al0.35Ga0.65N. By using various metals, this study also investigates how gate engineering affects the electrical characteristics of the GDC-HEMT. The lower ϕm (work function) of the Al-gate led to better DC/RF performance. When the Schottky barrier rises as a result of the conduction band edge being elevated, the performance reduces, and the threshold voltage (Vth) increases. Since it is essential to comprehend the role that source resistance (Rs) & drain resistance (Rd) play in RF design, we have also conducted simulations by varying the source-gate gap (LGS) & drain-gate gap (LGD). Due to low Rs & Rd, it was determined that the GDC-HEMT performed better at the smallest LGS & LGD. The extraordinary performance strongly highlights the immense potential and applicability of the GDC-HEMTs for future broadband power amplifiers.
{"title":"LG = 50 nm T-gated and Fe-doped double quantum well GaN‒HEMT on SiC wafer with graded AlGaN barrier for future power electronics applications","authors":"B. Mounika , J. Ajayan , Sandip Bhattacharya , D. Nirmal , Amit Krishna Dwivedi","doi":"10.1016/j.jsamd.2024.100795","DOIUrl":"10.1016/j.jsamd.2024.100795","url":null,"abstract":"<div><div>High-performance L<sub>G</sub> = 50 nm graded double-channel (GDC)-HEMT featuring AlN top barrier, recessed T-gate and graded-AlGaN bottom barrier is designed and investigated. Two quantum wells are formed in the AlN-GaN-graded AlGaN-GaN multilayer structure developed on a SiC substrate and the clear double hump feature of the transconductance (G<sub>M</sub>), cut-off frequency (f<sub>T</sub>), and capacitance plots clearly illustrates the double-channel (DC) behavior. The investigations carried out to explore the impact of barrier thickness (both AlN & graded-AlGaN) revealed superior performance with the G<sub>M</sub> showing two peaks at 181.5 & 488.1 mS/mm, the peak-drive-current (I<sub>D_peak</sub>) with V<sub>GS</sub> biased at 3 V is 1.81 A/mm, maximum saturation drain current of 3.08 A/mm (V<sub>GS</sub> = 3V), and the f<sub>T</sub> derived from the left- and right-hump are 263.7 GHz & 354.2 GHz, respectively, when both barriers are 6 nm thin, attributable to enhanced 2DEG density due to the coordination of channels because of proximity and lower leakage. It has been noticed that when the bottom barrier is thick, the DC behaviour is less obvious due to insufficient gate access to the lower channel. We investigated the impact of varying the Al % in AlGaN top barrier on the DC/RF performance of GDC-HEMTs, demonstrating enhanced performance with increased Al content, particularly for Al<sub>0.35</sub>Ga<sub>0.65</sub>N. By using various metals, this study also investigates how gate engineering affects the electrical characteristics of the GDC-HEMT. The lower ϕ<sub>m</sub> (work function) of the Al-gate led to better DC/RF performance. When the Schottky barrier rises as a result of the conduction band edge being elevated, the performance reduces, and the threshold voltage (V<sub>th</sub>) increases. Since it is essential to comprehend the role that source resistance (R<sub>s</sub>) & drain resistance (R<sub>d</sub>) play in RF design, we have also conducted simulations by varying the source-gate gap (L<sub>GS</sub>) & drain-gate gap (L<sub>GD</sub>). Due to low R<sub>s</sub> & R<sub>d</sub>, it was determined that the GDC-HEMT performed better at the smallest L<sub>GS</sub> & L<sub>GD</sub>. The extraordinary performance strongly highlights the immense potential and applicability of the GDC-HEMTs for future broadband power amplifiers.</div></div>","PeriodicalId":17219,"journal":{"name":"Journal of Science: Advanced Materials and Devices","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-10DOI: 10.1016/j.jsamd.2024.100803
Seungeun Baek , Dongkyoung Lee
The channels of the graphite-based bipolar plate for hydrogen fuel cells were mainly manufactured through milling due to low forming elongation and processability. However, during the milling process, the machining precision is low due to tool wear and vibration, and there is a risk of breakage. Non-traditional laser processing can solve the problems of tool wear and vibration through non-contact processing. In this study, the interaction characteristics of the nanosecond pulsed laser and CNT composites were observed, and channels and bipolar plates were manufactured. The effect of scanning speed and pulse duration was observed for interaction characteristics. Defects were observed due to high thermal effects at low scanning speed and high pulse duration. Channels were created depending on parallel pitch distance [] and Number of Scans (NOS). The channel was evaluated for depth, top width, bottom width, channel angle, material removal rate, and surface roughness, and significant changes were observed depending on . The chemical composition, surface resistance, and contact angle of the laser-processed channel were measured. The laser processed channel was oxidized, and the surface resistance and contact angle increased. Finally, the manufacturability of the CNT composites bipolar plate using laser was examined.
{"title":"A study on the manufacture of CNT composites bipolar plate for the fuel cell using a nanosecond pulsed laser","authors":"Seungeun Baek , Dongkyoung Lee","doi":"10.1016/j.jsamd.2024.100803","DOIUrl":"10.1016/j.jsamd.2024.100803","url":null,"abstract":"<div><div>The channels of the graphite-based bipolar plate for hydrogen fuel cells were mainly manufactured through milling due to low forming elongation and processability. However, during the milling process, the machining precision is low due to tool wear and vibration, and there is a risk of breakage. Non-traditional laser processing can solve the problems of tool wear and vibration through non-contact processing. In this study, the interaction characteristics of the nanosecond pulsed laser and CNT composites were observed, and channels and bipolar plates were manufactured. The effect of scanning speed and pulse duration was observed for interaction characteristics. Defects were observed due to high thermal effects at low scanning speed and high pulse duration. Channels were created depending on parallel pitch distance [<span><math><mrow><mo>Δ</mo><mi>S</mi></mrow></math></span>] and Number of Scans (NOS). The channel was evaluated for depth, top width, bottom width, channel angle, material removal rate, and surface roughness, and significant changes were observed depending on <span><math><mrow><mo>Δ</mo><mi>S</mi></mrow></math></span>. The chemical composition, surface resistance, and contact angle of the laser-processed channel were measured. The laser processed channel was oxidized, and the surface resistance and contact angle increased. Finally, the manufacturability of the CNT composites bipolar plate using laser was examined.</div></div>","PeriodicalId":17219,"journal":{"name":"Journal of Science: Advanced Materials and Devices","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-10DOI: 10.1016/j.jsamd.2024.100800
Yuan-Chang Liang, Chun-Hsi Yang
In this study, we used different sulfur sources (thiourea and sodium sulfide) in the hydrothermal vulcanization to create two types of Bi2S3/Bi2WO6 composite materials with different structures. We varied the vulcanization duration to control the degree of vulcanization of the samples. The composites made with sodium sulfide displayed a mix of particles and nanosheets, while those made with thiourea showed nanowires and nanosheets. The choice of sulfur source had a significant impact on the structural characteristics of the composite material. In photoelectrochemical experiments (PEC), the vulcanization-treated Bi2S3/Bi2WO6 composites improved significantly compared to the pristine Bi2WO6 template. In particular, the Bi2S3/Bi2WO6 composite prepared using sodium sulfide precursor for 4 h exhibited the best photocurrent density and the lowest charge transfer interface resistance. The improved performance is attributed to the suitable defect density and a Z-scheme mechanism facilitated by the built-in electric field at the interface, which effectively separated photogenerated carriers, increasing active species and significantly improving the composites' efficiency in PEC reactions.
{"title":"Unveiling the potential of decorating tunable morphology of bismuth sulfide nanostructures on the Bi2WO6 nanosheets for enhanced photoelectrochemical performance","authors":"Yuan-Chang Liang, Chun-Hsi Yang","doi":"10.1016/j.jsamd.2024.100800","DOIUrl":"10.1016/j.jsamd.2024.100800","url":null,"abstract":"<div><div>In this study, we used different sulfur sources (thiourea and sodium sulfide) in the hydrothermal vulcanization to create two types of Bi<sub>2</sub>S<sub>3</sub>/Bi<sub>2</sub>WO<sub>6</sub> composite materials with different structures. We varied the vulcanization duration to control the degree of vulcanization of the samples. The composites made with sodium sulfide displayed a mix of particles and nanosheets, while those made with thiourea showed nanowires and nanosheets. The choice of sulfur source had a significant impact on the structural characteristics of the composite material. In photoelectrochemical experiments (PEC), the vulcanization-treated Bi<sub>2</sub>S<sub>3</sub>/Bi<sub>2</sub>WO<sub>6</sub> composites improved significantly compared to the pristine Bi<sub>2</sub>WO<sub>6</sub> template. In particular, the Bi<sub>2</sub>S<sub>3</sub>/Bi<sub>2</sub>WO<sub>6</sub> composite prepared using sodium sulfide precursor for 4 h exhibited the best photocurrent density and the lowest charge transfer interface resistance. The improved performance is attributed to the suitable defect density and a Z-scheme mechanism facilitated by the built-in electric field at the interface, which effectively separated photogenerated carriers, increasing active species and significantly improving the composites' efficiency in PEC reactions.</div></div>","PeriodicalId":17219,"journal":{"name":"Journal of Science: Advanced Materials and Devices","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-10DOI: 10.1016/j.jsamd.2024.100796
N.L. Tuyen , N.T. Hue , P.T. Tho , H.N. Toan , C.T.A. Xuan , N.V. Dang , T.A. Ho , N.Q. Tuan , N. Tran
In this work, the SrFe12–xZnxO19 (Zn-SrM, x = 0, 0.1, 0.4, and 1.0) samples were fabricated using a combination of ball milling and heat treatment methods, which was simple and low-cost. Interestingly, the Zn-SrM samples exhibited great microwave absorption performances with an absorption rate of more than 99.99% and very thin thicknesses. The x = 0.1 sample could reach an excellent RL value of −40.08 dB at f = 17.88 GHz for a thickness of 1.45 mm. The x = 0.4 sample achieved a great RL value of −42.51 dB at 17.86 GHz and an EAB value of 1.29 GHz for t = 1.50 mm. With a thickness of 5.1 mm, the x = 1.0 sample could achieve a great RL value of −51.20 dB and an EAB value of 1.58 GHz. This microwave absorption performance, low cost, and simplicity of fabrication could confirm that Zn-SrM samples could be used as high-efficiency MAMs. The great microwave dissipating characteristics could be attributed to the high values of imaginary parts of complex permeability and complex permittivity leading to the high loss tangent, high degree of impedance matching, high values of attenuation constant and conductivity, suitable values of eddy current factor, and large numbers of semicircles in their Cole-Cole plots.
{"title":"Excellent microwave absorption performance of zinc-doped SrFe12O19 hexaferrite and detailed loss mechanism","authors":"N.L. Tuyen , N.T. Hue , P.T. Tho , H.N. Toan , C.T.A. Xuan , N.V. Dang , T.A. Ho , N.Q. Tuan , N. Tran","doi":"10.1016/j.jsamd.2024.100796","DOIUrl":"10.1016/j.jsamd.2024.100796","url":null,"abstract":"<div><div>In this work, the SrFe<sub>12–<em>x</em></sub>Zn<sub><em>x</em></sub>O<sub>19</sub> (Zn-SrM, <em>x</em> = 0, 0.1, 0.4, and 1.0) samples were fabricated using a combination of ball milling and heat treatment methods, which was simple and low-cost. Interestingly, the Zn-SrM samples exhibited great microwave absorption performances with an absorption rate of more than 99.99% and very thin thicknesses. The <em>x</em> = 0.1 sample could reach an excellent RL value of −40.08 dB at <em>f</em> = 17.88 GHz for a thickness of 1.45 mm. The <em>x</em> = 0.4 sample achieved a great RL value of −42.51 dB at 17.86 GHz and an EAB value of 1.29 GHz for <em>t</em> = 1.50 mm. With a thickness of 5.1 mm, the <em>x</em> = 1.0 sample could achieve a great RL value of −51.20 dB and an EAB value of 1.58 GHz. This microwave absorption performance, low cost, and simplicity of fabrication could confirm that Zn-SrM samples could be used as high-efficiency MAMs. The great microwave dissipating characteristics could be attributed to the high values of imaginary parts of complex permeability and complex permittivity leading to the high loss tangent, high degree of impedance matching, high values of attenuation constant and conductivity, suitable values of eddy current factor, and large numbers of semicircles in their Cole-Cole plots.</div></div>","PeriodicalId":17219,"journal":{"name":"Journal of Science: Advanced Materials and Devices","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-10DOI: 10.1016/j.jsamd.2024.100794
James Bourely, Danick Briand
Monitoring the temperature of perishable goods during transport and storage is essential to prevent waste and maintain product quality. Exploiting the unique property of phase-change materials (PCM), altering their physical state at specific temperatures, we optimize a capacitive sensor design based on a copper on polyimide interdigitated spiral (IDE) structure coated with a PCM to irreversibly detect temperature thresholds. The effect of the sensor dimensioning on its response is analyzed using a finite element model simulation. The model predicted up to 51% capacitance variation for optimal coverage of the PCM after spreading over the IDE, which was validated experimentally within a 5% error. Two melting concepts utilizing the spreading or the removal of the melted PCM over the IDE are investigated based on a capillary retention mechanism to maintain sensor sensitivity under inclination. Finally, an eco-friendly implementation of the capacitive structure and its wireless operation at 460 MHz is demonstrated on paper with a printed zinc transducer passivated with beeswax and covered with jojoba oil. Melting of the oil at a threshold temperature of 12.3 °C resulted in an irreversible shift in resonance frequency of 14 MHz. This study provides guidelines for the design and implementation of irreversible temperature monitoring capacitive sensors.
监测易腐货物在运输和储存过程中的温度对于防止浪费和保持产品质量至关重要。利用相变材料 (PCM) 在特定温度下会改变物理状态的独特特性，我们优化了一种电容式传感器的设计，该传感器基于涂有 PCM 的聚酰亚胺间螺旋 (IDE) 铜结构，能够不可逆地检测温度阈值。我们使用有限元模型模拟分析了传感器尺寸对其响应的影响。该模型预测，在 IDE 上铺设 PCM 后，最佳覆盖范围内的电容变化可达 51%，实验验证了这一预测，误差不超过 5%。在毛细管保持机制的基础上，研究了两种熔化概念，即在 IDE 上铺展或移除熔化的 PCM，以保持传感器在倾斜状态下的灵敏度。最后，在纸上展示了一种环保的电容式结构及其在 460 MHz 频率下的无线操作，该结构是用蜂蜡钝化并覆盖荷荷巴油的印刷锌传感器。在 12.3 °C 的临界温度下，油的熔化导致共振频率不可逆转地移动了 14 MHz。这项研究为不可逆温度监测电容式传感器的设计和实施提供了指导。
{"title":"Design optimization of a phase-change capacitive sensor for irreversible temperature threshold monitoring and its eco-friendly and wireless implementation","authors":"James Bourely, Danick Briand","doi":"10.1016/j.jsamd.2024.100794","DOIUrl":"10.1016/j.jsamd.2024.100794","url":null,"abstract":"<div><div>Monitoring the temperature of perishable goods during transport and storage is essential to prevent waste and maintain product quality. Exploiting the unique property of phase-change materials (PCM), altering their physical state at specific temperatures, we optimize a capacitive sensor design based on a copper on polyimide interdigitated spiral (IDE) structure coated with a PCM to irreversibly detect temperature thresholds. The effect of the sensor dimensioning on its response is analyzed using a finite element model simulation. The model predicted up to 51% capacitance variation for optimal coverage of the PCM after spreading over the IDE, which was validated experimentally within a 5% error. Two melting concepts utilizing the spreading or the removal of the melted PCM over the IDE are investigated based on a capillary retention mechanism to maintain sensor sensitivity under inclination. Finally, an eco-friendly implementation of the capacitive structure and its wireless operation at 460 MHz is demonstrated on paper with a printed zinc transducer passivated with beeswax and covered with jojoba oil. Melting of the oil at a threshold temperature of 12.3 °C resulted in an irreversible shift in resonance frequency of 14 MHz. This study provides guidelines for the design and implementation of irreversible temperature monitoring capacitive sensors.</div></div>","PeriodicalId":17219,"journal":{"name":"Journal of Science: Advanced Materials and Devices","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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