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":"9 4","pages":"Article 100799"},"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":"9 4","pages":"Article 100804"},"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":"9 4","pages":"Article 100795"},"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":"9 4","pages":"Article 100803"},"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":"9 4","pages":"Article 100800"},"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.2024.100794
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":"9 4","pages":"Article 100794"},"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}
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":"9 4","pages":"Article 100796"},"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 : 2024-10-09DOI: 10.1016/j.jsamd.2024.100802
Abdu Saeed , Amal Mohsen Alghamdi , Maha Aiiad Alenizi , Reem Alwafi , G.M. Asnag , Eman Alzahrani , Randa A. Althobiti , Ahmed N. Al-Hakimi , Aeshah Salem , S.A. Al-Ghamdi
With the rising global energy demands, there is a pressing need for the invention of efficient and reliable energy storage systems. This research centers on the creation and analysis of flexible dielectric capacitors composed of polymer nanocomposites (PNCs), incorporating a blend of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) as the base polymer, with multi-walled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs) serving as nanofillers. The AuNPs were produced through an environmentally friendly synthesis method. Films made from PVA/PVP blended with MWCNTs and AuNPs were fabricated using the casting approach. Various characterization methods, including TEM, XRD, FTIR, and UV–Vis spectroscopy, were utilized to evaluate the samples. A detailed analysis of their electrical/dielectric characteristics was conducted. XRD analysis revealed a significant decrease in crystallinity from 55% for the pure PVA/PVP blend to 37% for the 1.6 wt% nanofiller composite, indicating increased amorphous content, which facilitates better ion mobility. FTIR confirmed strong interactions between the polymer matrix and nanofillers, with intensified vibrational peaks pointing to enhanced molecular dynamics. UV–Vis spectroscopy demonstrated a red shift in the absorption edge, and Tauc plot analysis showed a reduction in the indirect/direct optical band gap from 4.84 eV/5.68 eV for the pure blend to 4.26/5.35 eV for the nanocomposite with 1.6 wt% nanofillers. The addition of nanofillers resulted in improvements in their dielectric features, which exhibited a significant performance improvement, with the dielectric constant (ε′) reaching approximately 1100 at low frequency for the 1.6 wt% nanofiller sample, compared to 9 for the pure blend. Additionally, the dielectric loss (ε'') and tangent loss (tan δ) were reduced, with tan δ showing a decrease from 15 for the pure blend to 2 for the 1.6 wt% nanofiller composite at low frequency, indicating enhanced dielectric efficiency and reduced energy dissipation. The capacitors' functionality was assessed through capacitance-frequency and conductance-frequency analyses. The capacitors exhibited stable high capacitance across a broad frequency spectrum, making them alternatives for energy storage solutions.
{"title":"Preparation and investigation of structural, optical, and dielectric properties of PVA/PVP blend films boosted by MWCNTs/AuNPs for dielectric capacitor applications","authors":"Abdu Saeed , Amal Mohsen Alghamdi , Maha Aiiad Alenizi , Reem Alwafi , G.M. Asnag , Eman Alzahrani , Randa A. Althobiti , Ahmed N. Al-Hakimi , Aeshah Salem , S.A. Al-Ghamdi","doi":"10.1016/j.jsamd.2024.100802","DOIUrl":"10.1016/j.jsamd.2024.100802","url":null,"abstract":"<div><div>With the rising global energy demands, there is a pressing need for the invention of efficient and reliable energy storage systems. This research centers on the creation and analysis of flexible dielectric capacitors composed of polymer nanocomposites (PNCs), incorporating a blend of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) as the base polymer, with multi-walled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs) serving as nanofillers. The AuNPs were produced through an environmentally friendly synthesis method. Films made from PVA/PVP blended with MWCNTs and AuNPs were fabricated using the casting approach. Various characterization methods, including TEM, XRD, FTIR, and UV–Vis spectroscopy, were utilized to evaluate the samples. A detailed analysis of their electrical/dielectric characteristics was conducted. XRD analysis revealed a significant decrease in crystallinity from 55% for the pure PVA/PVP blend to 37% for the 1.6 wt% nanofiller composite, indicating increased amorphous content, which facilitates better ion mobility. FTIR confirmed strong interactions between the polymer matrix and nanofillers, with intensified vibrational peaks pointing to enhanced molecular dynamics. UV–Vis spectroscopy demonstrated a red shift in the absorption edge, and Tauc plot analysis showed a reduction in the indirect/direct optical band gap from 4.84 eV/5.68 eV for the pure blend to 4.26/5.35 eV for the nanocomposite with 1.6 wt% nanofillers. The addition of nanofillers resulted in improvements in their dielectric features, which exhibited a significant performance improvement, with the dielectric constant (<em>ε</em>′) reaching approximately 1100 at low frequency for the 1.6 wt% nanofiller sample, compared to 9 for the pure blend. Additionally, the dielectric loss (<em>ε</em>'') and tangent loss (tan δ) were reduced, with tan δ showing a decrease from 15 for the pure blend to 2 for the 1.6 wt% nanofiller composite at low frequency, indicating enhanced dielectric efficiency and reduced energy dissipation. The capacitors' functionality was assessed through capacitance-frequency and conductance-frequency analyses. The capacitors exhibited stable high capacitance across a broad frequency spectrum, making them alternatives for energy storage solutions.</div></div>","PeriodicalId":17219,"journal":{"name":"Journal of Science: Advanced Materials and Devices","volume":"9 4","pages":"Article 100802"},"PeriodicalIF":6.7,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142442334","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}
Polyethylene-based separators are generally unsuitable for aqueous supercapacitors due to their poor wettability with the electrolyte, which impedes ion transport. However, incorporating Triton X-100 (2-[4-(2,4,4-trimethylpentan-2-yl)phenoxy]ethanol) into the aqueous sulfuric acid (H2SO4) electrolyte improves the wettability of polyethylene and facilitates ionic movement through its pores. In this study, Triton X-100 was added to 1.0 M H2SO4 at various concentrations (0.122%–1.210% V/V) to evaluate its impact on supercapacitor performance. Supercapacitors were assembled using activated carbon-filled carbon cloth electrodes, each of the above electrolytes and polyethylene sheet separators. Scanning electron microscopy revealed that the carbon cloth exhibited a uniform fiber distribution and high surface area for activated carbon integration. The polyethylene separator displayed a porous structure with an average pore size of 165 ± 35 nm. Triton X-100 significantly reduced the water contact angle from 101.5° (without surfactant) to 30.2° (with 1.21% V/V Triton X-100), enhancing polyethylene’s wettability. This change from hydrophobic to hydrophilic characteristics enabled the formation of an electrical double layer at the separator/electrolyte interface, improving ionic transport. However, higher Triton X-100 concentrations increased the electrolyte's viscosity, which impeded ion movement. The highest specific capacitance of 55.3 F/g (at a scan rate of 0.005 V s−1) was achieved with 0.488% V/V Triton X-100. The specific capacitance varied with surfactant concentration in a complex manner, influenced by micelle formation and precipitation. These findings were corroborated by cyclic voltammetry and AC impedance spectroscopy.
{"title":"Effect of Triton X-100 surfactant concentration on the wettability of polyethylene-based separators used in supercapacitors","authors":"S.M.B. Dissanayake , I.G.K.J. Wimalasena , N.M. Keppetipola , B.C. Karunarathne , A.D.T. Medagedara , Ludmila Cojocaru , Satoshi Uchida , R.M.G. Rajapakse , Kirthi Tennakone , Masamichi Yoshimura , G.R.A. Kumara","doi":"10.1016/j.jsamd.2024.100801","DOIUrl":"10.1016/j.jsamd.2024.100801","url":null,"abstract":"<div><div>Polyethylene-based separators are generally unsuitable for aqueous supercapacitors due to their poor wettability with the electrolyte, which impedes ion transport. However, incorporating Triton X-100 (2-[4-(2,4,4-trimethylpentan-2-yl)phenoxy]ethanol) into the aqueous sulfuric acid (H<sub>2</sub>SO<sub>4</sub>) electrolyte improves the wettability of polyethylene and facilitates ionic movement through its pores. In this study, Triton X-100 was added to 1.0 M H<sub>2</sub>SO<sub>4</sub> at various concentrations (0.122%–1.210% V/V) to evaluate its impact on supercapacitor performance. Supercapacitors were assembled using activated carbon-filled carbon cloth electrodes, each of the above electrolytes and polyethylene sheet separators. Scanning electron microscopy revealed that the carbon cloth exhibited a uniform fiber distribution and high surface area for activated carbon integration. The polyethylene separator displayed a porous structure with an average pore size of 165 ± 35 nm. Triton X-100 significantly reduced the water contact angle from 101.5° (without surfactant) to 30.2° (with 1.21% V/V Triton X-100), enhancing polyethylene’s wettability. This change from hydrophobic to hydrophilic characteristics enabled the formation of an electrical double layer at the separator/electrolyte interface, improving ionic transport. However, higher Triton X-100 concentrations increased the electrolyte's viscosity, which impeded ion movement. The highest specific capacitance of 55.3 F/g (at a scan rate of 0.005 V s<sup>−1</sup>) was achieved with 0.488% V/V Triton X-100. The specific capacitance varied with surfactant concentration in a complex manner, influenced by micelle formation and precipitation. These findings were corroborated by cyclic voltammetry and AC impedance spectroscopy.</div></div>","PeriodicalId":17219,"journal":{"name":"Journal of Science: Advanced Materials and Devices","volume":"9 4","pages":"Article 100801"},"PeriodicalIF":6.7,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534616","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 : 2024-09-26DOI: 10.1016/j.jsamd.2024.100790
Rami Alfattani, Mohammed Yunus
Mechanical and Corrosion characteristics of composite materials made from Aluminum alloys (AA) 6063 supplanting as the material of choice for automotive, aerospace, and marine applications by systematically varying ceramic reinforcements developed through controlled stir cast technique ensuring uniform dispersion are explored. The hardness, density, impact and tensile strength, corrosion resistance, and microstructural characteristics of Aluminum Matrix Composites (AMCs) reinforced with titanium diboride (TiB2) at 7.5, 10, and 12.5 wt% and chromium oxide (Cr2O3) at 3, 6, and 9 wt% were assessed according to ASTM standards. The microstructural analysis revealed a reduction in the growth of reinforcement clusters within acceptable limits. The addition of reinforcements to the matrix resulted in improved tensile strength, ranging from 124.6 to 188.7 MPa, and hardness, increasing from 71.5 to 144.32 VHN. This improvement is attributed to the strengthening or load transfer mechanism facilitated by the reinforcements. Additionally, the impact strength of the composites increased from 11.845 to 21.16 J, while the density showed slight variations. Consistent corrosion tests demonstrated that the chemical and interfacial interactions between the matrix material and the reinforcements significantly enhanced the corrosion resistance, reducing the corrosion rate from 570 to 499 mm/year.
{"title":"Explorations of mechanical and corrosion resistance properties of AA6063/TiB2/Cr2O3 hybrid composites produced by stir casting","authors":"Rami Alfattani, Mohammed Yunus","doi":"10.1016/j.jsamd.2024.100790","DOIUrl":"10.1016/j.jsamd.2024.100790","url":null,"abstract":"<div><div>Mechanical and Corrosion characteristics of composite materials made from Aluminum alloys (AA) 6063 supplanting as the material of choice for automotive, aerospace, and marine applications by systematically varying ceramic reinforcements developed through controlled stir cast technique ensuring uniform dispersion are explored. The hardness, density, impact and tensile strength, corrosion resistance, and microstructural characteristics of Aluminum Matrix Composites (AMCs) reinforced with titanium diboride (TiB<sub>2</sub>) at 7.5, 10, and 12.5 wt% and chromium oxide (Cr<sub>2</sub>O<sub>3</sub>) at 3, 6, and 9 wt% were assessed according to ASTM standards. The microstructural analysis revealed a reduction in the growth of reinforcement clusters within acceptable limits. The addition of reinforcements to the matrix resulted in improved tensile strength, ranging from 124.6 to 188.7 MPa, and hardness, increasing from 71.5 to 144.32 VHN. This improvement is attributed to the strengthening or load transfer mechanism facilitated by the reinforcements. Additionally, the impact strength of the composites increased from 11.845 to 21.16 J, while the density showed slight variations. Consistent corrosion tests demonstrated that the chemical and interfacial interactions between the matrix material and the reinforcements significantly enhanced the corrosion resistance, reducing the corrosion rate from 570 to 499 mm/year.</div></div>","PeriodicalId":17219,"journal":{"name":"Journal of Science: Advanced Materials and Devices","volume":"9 4","pages":"Article 100790"},"PeriodicalIF":6.7,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421812","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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