Pub Date : 2023-04-25DOI: 10.1088/2058-8585/acd010
Govind S. Ekbote, M. Khalifa, B. Venkatesa Perumal, S. Anandhan
Lead-free flexible piezoelectric nanogenerator (PNG) and triboelectric nanogenerator (TENG) are sought after due to their ability to produce electricity by harnessing wasteful mechanical energy. A comprehensive understanding of additives and processing techniques is crucial for fine-tuning the performance of such energy systems. We have investigated in detail the effect of the addition of reverse microemulsion synthesized barium tungstate nanorods (BWN) on morphology, crystallinity, polymorphism of electrospun nanofabrics of poly(vinylidene fluoride) (PVDF). The electroactive phase content of the nanofabrics was enhanced upon the addition of BWN and the highest electroactive phase content of 86.5% was observed in the nanofabric containing 3 wt% of BWN. The dielectric constant of the nanofabric containing 5 wt% BWN was ∼1.96 times higher than that of pristine electrospun PVDF nanofabric (EPVDF). The ratio of relative change in the capacitance to initial capacitance of the sensor fabricated from the same system was ∼4 times greater than that of EPVDF. Consequently, its piezoelectric and triboelectric performances were improved. The PNG fabricated using the nanofabric containing 3 wt% BWN produced the highest open-circuit voltage of 8 V under an applied load of 8 N. A TENG made using the same system was able to produce a voltage output of 200 V, which was 1.77 times as high as that of EPVDF under one-finger tapping in contact-separation mode. The same composite nanofabric produced piezoelectric and triboelectric power densities of 4.3 µW cm−2 and 646 µW cm−2, respectively. The TENG was able to light 40 LEDs under one finger tapping. Fluttering-driven TENG fabricated using the aforementioned nanofabric was able to produce a triboelectric voltage of 84 V at a wind speed of 7 m s−1. Overall, these nanofabrics could be a potential material for energy harvesting devices for powering wearable devices, environmental sensors, and internet of things.
无铅柔性压电纳米发电机(PNG)和摩擦电纳米发电机(TENG)因其利用浪费的机械能发电的能力而受到追捧。对添加剂和加工技术的全面了解对于微调此类能源系统的性能至关重要。研究了添加反相微乳液合成的钨酸钡纳米棒(BWN)对聚偏氟乙烯(PVDF)静电纺丝纳米织物形貌、结晶度和多态性的影响。BWN的加入提高了纳米织物的电活性相含量，当BWN含量为3wt %时，纳米织物的电活性相含量最高，为86.5%。含有5 wt% BWN的纳米织物的介电常数比原始静电纺PVDF纳米织物(EPVDF)高约1.96倍。由同一体系制备的传感器的电容与初始电容的相对变化率比EPVDF大4倍。从而提高了其压电和摩擦电性能。使用含有3 wt% BWN的纳米织物制成的PNG在施加8 n的负载下产生最高的开路电压8 V，使用相同系统制成的TENG能够产生200 V的输出电压，这是在触点分离模式下单指轻敲EPVDF的1.77倍。同样的复合纳米织物产生的压电和摩擦电功率密度分别为4.3µW cm−2和646µW cm−2。TENG可以在一个手指轻敲下点亮40个led。使用上述纳米织物制造的颤振驱动TENG能够在7 m s - 1的风速下产生84 V的摩擦电压。总的来说，这些纳米织物可能是为可穿戴设备、环境传感器和物联网供电的能量收集设备的潜在材料。
{"title":"Development of a flexible piezoelectric and triboelectric energy harvester with piezo capacitive sensing ability from barium tungstate nanorod-dispersed PVDF nanofabrics","authors":"Govind S. Ekbote, M. Khalifa, B. Venkatesa Perumal, S. Anandhan","doi":"10.1088/2058-8585/acd010","DOIUrl":"https://doi.org/10.1088/2058-8585/acd010","url":null,"abstract":"Lead-free flexible piezoelectric nanogenerator (PNG) and triboelectric nanogenerator (TENG) are sought after due to their ability to produce electricity by harnessing wasteful mechanical energy. A comprehensive understanding of additives and processing techniques is crucial for fine-tuning the performance of such energy systems. We have investigated in detail the effect of the addition of reverse microemulsion synthesized barium tungstate nanorods (BWN) on morphology, crystallinity, polymorphism of electrospun nanofabrics of poly(vinylidene fluoride) (PVDF). The electroactive phase content of the nanofabrics was enhanced upon the addition of BWN and the highest electroactive phase content of 86.5% was observed in the nanofabric containing 3 wt% of BWN. The dielectric constant of the nanofabric containing 5 wt% BWN was ∼1.96 times higher than that of pristine electrospun PVDF nanofabric (EPVDF). The ratio of relative change in the capacitance to initial capacitance of the sensor fabricated from the same system was ∼4 times greater than that of EPVDF. Consequently, its piezoelectric and triboelectric performances were improved. The PNG fabricated using the nanofabric containing 3 wt% BWN produced the highest open-circuit voltage of 8 V under an applied load of 8 N. A TENG made using the same system was able to produce a voltage output of 200 V, which was 1.77 times as high as that of EPVDF under one-finger tapping in contact-separation mode. The same composite nanofabric produced piezoelectric and triboelectric power densities of 4.3 µW cm−2 and 646 µW cm−2, respectively. The TENG was able to light 40 LEDs under one finger tapping. Fluttering-driven TENG fabricated using the aforementioned nanofabric was able to produce a triboelectric voltage of 84 V at a wind speed of 7 m s−1. Overall, these nanofabrics could be a potential material for energy harvesting devices for powering wearable devices, environmental sensors, and internet of things.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42094600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-22DOI: 10.1088/2058-8585/accf6a
I. Shuvo, J. Decaens, P. Dolez
Joule heating textiles are available on the market for a variety of applications. However, their market growth is limited by challenges in terms of quality, for instance with the need to provide a reliable account of the heating to be expected, prevent the occurrence of overheating leading to burns and fires, and ensure the long-term performance when exposed to use conditions such as abrasion and laundering. Standard test methods are a key component to solve these issues of efficiency, safety, and durability. Yet, they mostly remain to be established. In this research, a test method was developed for the characterization of the Joule heating efficiency of electric textiles. It involves measuring the temperature of a heating textile using a thermocouple affixed to its surface while it is powered for an hour. The value of the surface temperature that would ultimately be reached by the heating textile after an infinite heating time and the time for the temperature to enter a slow increase regime are determined by fitting an equation to the temperature-time data. These two parameters provide a quantitative mean of comparison between different heating textiles/conditions. This test method was used to analyze the effect of different experimental conditions on the heating efficiency of four heaters corresponding to different technologies of Joule heating textiles and make recommendations in terms of conditions for a standardized test protocol. These results give some insights towards the development of a robust and universal test method for the quantitative assessment of the Joule heating efficiency of electrical textiles that will ultimately be proposed for standardization to help support the growth of the e-textile industry.
{"title":"Characterization method of the Joule heating efficiency of electric textiles and influence of boundary conditions","authors":"I. Shuvo, J. Decaens, P. Dolez","doi":"10.1088/2058-8585/accf6a","DOIUrl":"https://doi.org/10.1088/2058-8585/accf6a","url":null,"abstract":"Joule heating textiles are available on the market for a variety of applications. However, their market growth is limited by challenges in terms of quality, for instance with the need to provide a reliable account of the heating to be expected, prevent the occurrence of overheating leading to burns and fires, and ensure the long-term performance when exposed to use conditions such as abrasion and laundering. Standard test methods are a key component to solve these issues of efficiency, safety, and durability. Yet, they mostly remain to be established. In this research, a test method was developed for the characterization of the Joule heating efficiency of electric textiles. It involves measuring the temperature of a heating textile using a thermocouple affixed to its surface while it is powered for an hour. The value of the surface temperature that would ultimately be reached by the heating textile after an infinite heating time and the time for the temperature to enter a slow increase regime are determined by fitting an equation to the temperature-time data. These two parameters provide a quantitative mean of comparison between different heating textiles/conditions. This test method was used to analyze the effect of different experimental conditions on the heating efficiency of four heaters corresponding to different technologies of Joule heating textiles and make recommendations in terms of conditions for a standardized test protocol. These results give some insights towards the development of a robust and universal test method for the quantitative assessment of the Joule heating efficiency of electrical textiles that will ultimately be proposed for standardization to help support the growth of the e-textile industry.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42864205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-21DOI: 10.1088/2058-8585/accf26
Paulo Luís, D. Southee, George W. Weaver, Upul Wijayantha
Metal-based materials, such as silver or copper, are highly desired as current collector materials for flexible energy storage due to their excellent electrical properties but lack the long-term operational electrochemical stability. Herein we report a method to prevent the corrosion of such materials, while fully exploiting their electrical properties. This was achieved by covering the current collector with an electrochemically stable conductive carbon-based layer. The barrier layer allows the flow of charge between the electrically conductive elements of the textile composite electrodes, while protecting the current collector from contacting the electrolyte. The areal power and energy densities obtained after 1000 bending cycles were 29.88 and 0.01 mWh cm−2, respectively, with no evident degradation. Additionally, patterned current collectors were designed to deposit lower quantities of ink, without detriment to electrochemical performance. After 1000 bending cycles, the textile composite supercapacitors (TCSs) having 50% less current collector material demonstrated an areal power and energy density of 28.08 and 0.01 mWh cm−2, respectively. The proposed strategy is essential in enabling the utilisation of highly conductive metal-based inks, improving the rate capabilities and long-term operation of wearable energy storage devices, while maximising specific power and energy densities of TCSs, and decreasing the manufacturing cost.
金属基材料，如银或铜，由于其优异的电学性能，但缺乏长期操作的电化学稳定性，因此非常需要作为柔性储能的集流材料。在此，我们报告了一种方法，以防止这些材料的腐蚀，同时充分利用其电性能。这是通过在电流收集器上覆盖一层电化学稳定的导电碳基层来实现的。阻挡层允许电荷在纺织复合电极的导电元件之间流动，同时保护电流收集器不与电解质接触。1000次弯曲循环后得到的面功率和能量密度分别为29.88和0.01 mWh cm−2，没有明显的退化。此外，图案集流器被设计成沉积较少数量的油墨，而不会损害电化学性能。经过1000次弯曲循环后，具有较少50%集流材料的纺织复合材料超级电容器(TCSs)的面功率和能量密度分别为28.08和0.01 mWh cm - 2。所提出的策略对于实现高导电性金属基油墨的利用，提高可穿戴储能设备的速率能力和长期运行，同时最大化TCSs的比功率和能量密度，并降低制造成本至关重要。
{"title":"Novel approach to utilise highly conductive but electrochemically unstable current collector materials in textile supercapacitor electrodes","authors":"Paulo Luís, D. Southee, George W. Weaver, Upul Wijayantha","doi":"10.1088/2058-8585/accf26","DOIUrl":"https://doi.org/10.1088/2058-8585/accf26","url":null,"abstract":"Metal-based materials, such as silver or copper, are highly desired as current collector materials for flexible energy storage due to their excellent electrical properties but lack the long-term operational electrochemical stability. Herein we report a method to prevent the corrosion of such materials, while fully exploiting their electrical properties. This was achieved by covering the current collector with an electrochemically stable conductive carbon-based layer. The barrier layer allows the flow of charge between the electrically conductive elements of the textile composite electrodes, while protecting the current collector from contacting the electrolyte. The areal power and energy densities obtained after 1000 bending cycles were 29.88 and 0.01 mWh cm−2, respectively, with no evident degradation. Additionally, patterned current collectors were designed to deposit lower quantities of ink, without detriment to electrochemical performance. After 1000 bending cycles, the textile composite supercapacitors (TCSs) having 50% less current collector material demonstrated an areal power and energy density of 28.08 and 0.01 mWh cm−2, respectively. The proposed strategy is essential in enabling the utilisation of highly conductive metal-based inks, improving the rate capabilities and long-term operation of wearable energy storage devices, while maximising specific power and energy densities of TCSs, and decreasing the manufacturing cost.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43052367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-14DOI: 10.1088/2058-8585/accd05
Juho Kerminen, Boxuan Xie, Lauri Mela, A. Karakoç, K. Ruttik, R. Jäntti
The present study introduces an inkjet-printed flexible coplanar waveguide patch antenna array concept. Single antenna and four-element antenna arrays were characterized, which were attached to a subminiature version A connector via an innovative solderless, 3D-printed ‘plug-and-play-type’ tightener. Furthermore, indoor wireless communication and Internet of Things scenarios with commonly used wall materials including gypsum and plywood boards, on which patch antennas and antenna arrays can be attached, were also presented. In order to validate the concept, design and fabrication iterations in parallel with numerical and experimental investigations were executed. To elaborate, single antenna and antenna array configurations without and with wall materials were characterized to see their functionality at 2.4 GHz resonance frequency and beyond 300 MHz bandwidth, respectively. The results demonstrate that the investigated configurations fulfill short-range radio transmission and can be utilized, e.g., for indoor backscattering-type communications and wireless sensing applications, as an affordable and versatile alternative to their conventional counterparts. Being attached to their corresponding background materials, single-antenna specimens were measured to have return losses beyond 18 dB and peak gains around 1 dBi, while higher peak gains above 6 dBi were detected for antenna arrays. Moreover, the antenna arrays can enable multiple-input and multiple-output communication. The proposed arrays had diversity performance in terms of return losses higher than 15 dB, isolation of more than 20 dB, envelope correlation coefficient <0.001 , diversity gain >9.95 dB, mean effective gain <−3 dB, power ratio factor <0.5 dB, and channel capacity loss <0.4 bits/s/Hz.
{"title":"Low-cost thin film patch antennas and antenna arrays with various background wall materials for indoor wireless communications","authors":"Juho Kerminen, Boxuan Xie, Lauri Mela, A. Karakoç, K. Ruttik, R. Jäntti","doi":"10.1088/2058-8585/accd05","DOIUrl":"https://doi.org/10.1088/2058-8585/accd05","url":null,"abstract":"The present study introduces an inkjet-printed flexible coplanar waveguide patch antenna array concept. Single antenna and four-element antenna arrays were characterized, which were attached to a subminiature version A connector via an innovative solderless, 3D-printed ‘plug-and-play-type’ tightener. Furthermore, indoor wireless communication and Internet of Things scenarios with commonly used wall materials including gypsum and plywood boards, on which patch antennas and antenna arrays can be attached, were also presented. In order to validate the concept, design and fabrication iterations in parallel with numerical and experimental investigations were executed. To elaborate, single antenna and antenna array configurations without and with wall materials were characterized to see their functionality at 2.4 GHz resonance frequency and beyond 300 MHz bandwidth, respectively. The results demonstrate that the investigated configurations fulfill short-range radio transmission and can be utilized, e.g., for indoor backscattering-type communications and wireless sensing applications, as an affordable and versatile alternative to their conventional counterparts. Being attached to their corresponding background materials, single-antenna specimens were measured to have return losses beyond 18 dB and peak gains around 1 dBi, while higher peak gains above 6 dBi were detected for antenna arrays. Moreover, the antenna arrays can enable multiple-input and multiple-output communication. The proposed arrays had diversity performance in terms of return losses higher than 15 dB, isolation of more than 20 dB, envelope correlation coefficient <0.001 , diversity gain >9.95 dB, mean effective gain <−3 dB, power ratio factor <0.5 dB, and channel capacity loss <0.4 bits/s/Hz.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48104048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-13DOI: 10.1088/2058-8585/accc9b
Zhao Fu, P. Tanninen, J. Keskinen, Roman Lev, Ville Leminen, M. Mäntysalo
In this research, we conducted a wear test on inkjet-printed silver conductors using different loads and counter materials (two paperboards, brushed steel sheet, and sandpaper) with similar surface roughness values. The conductor’s reliability was characterized by resistance measurement, the failures and tested counter materials were analyzed using an optical microscope, profilometer, scanning electron microscope, and energy dispersive spectrometer. It was found that the counter material has a dominant impact on a conductor’s reliability and failure mechanism compared with load. The conductors were exceptionally reliable but subject to adhesive wear when tested by paperboards. They were also highly reliable when tested by brushed steel sheet although the silver became severely detached, and the conductivity was lost suddenly when a major scratch was caused by two-body and three-body abrasive wear mechanisms. Sandpaper rubbing caused the most severe silver detachment and quick loss of conductivity, as a large amount of small-size (5–15 µm) silicon carbide particles with sharp edges and corners caused a dense cutting effect via two-body abrasive wear (by cutting) mechanism. Additionally, the failures in almost all samples occurred in the areas in contact with the counter edges, suggesting that failure was accelerated by the edge effect. This study proves that inkjet-printed electronics on the investigated paperboard is exceptionally durable when rubbed by paperboards and steel sheets, and thus provides a reliable solution to intelligent packaging. To promote intelligent packaging, more paperboards, as well as approaches for reducing the edge effect can be investigated.
{"title":"Wear reliability and failure mechanism of inkjet-printed conductors on paperboard substrate","authors":"Zhao Fu, P. Tanninen, J. Keskinen, Roman Lev, Ville Leminen, M. Mäntysalo","doi":"10.1088/2058-8585/accc9b","DOIUrl":"https://doi.org/10.1088/2058-8585/accc9b","url":null,"abstract":"In this research, we conducted a wear test on inkjet-printed silver conductors using different loads and counter materials (two paperboards, brushed steel sheet, and sandpaper) with similar surface roughness values. The conductor’s reliability was characterized by resistance measurement, the failures and tested counter materials were analyzed using an optical microscope, profilometer, scanning electron microscope, and energy dispersive spectrometer. It was found that the counter material has a dominant impact on a conductor’s reliability and failure mechanism compared with load. The conductors were exceptionally reliable but subject to adhesive wear when tested by paperboards. They were also highly reliable when tested by brushed steel sheet although the silver became severely detached, and the conductivity was lost suddenly when a major scratch was caused by two-body and three-body abrasive wear mechanisms. Sandpaper rubbing caused the most severe silver detachment and quick loss of conductivity, as a large amount of small-size (5–15 µm) silicon carbide particles with sharp edges and corners caused a dense cutting effect via two-body abrasive wear (by cutting) mechanism. Additionally, the failures in almost all samples occurred in the areas in contact with the counter edges, suggesting that failure was accelerated by the edge effect. This study proves that inkjet-printed electronics on the investigated paperboard is exceptionally durable when rubbed by paperboards and steel sheets, and thus provides a reliable solution to intelligent packaging. To promote intelligent packaging, more paperboards, as well as approaches for reducing the edge effect can be investigated.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43856143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-06DOI: 10.1088/2058-8585/accaf6
Jonghyun Jeong, Gihak Kim, Jaewook Jeong
In this paper, stretchable electrodes adopting a double stress release structure were fabricated and characterized on eco-flex substrates. First, the correlation between mechanical properties applying surface plasma treatment and stretching capability of stretchable silver electrodes directly deposited on eco-flex substrate was studied. The Young’s modulus values of the substrate and metal were extracted using the force-distance relation via atomic force microscopy employing Johnson–Kendall–Roberts model. It was found that, as the Young’s modulus increased with the increase of plasma treatment time, the stretching capability first improved; then, samples showed no improvement over long plasma treatment time. This indicates that there is an optimum plasma treatment time to simultaneously achieve high stretching capability and low initial resistance. Using the optimum time, stretchable silver electrodes adopting double stress release structure along lateral and vertical directions were fabricated and the high stretching capability of the silver electrodes was achieved up to tensile strain of about 160%, as was high stability of up to 1000 times the multi-cycling strain.
{"title":"Stretchable silver electrodes adopting double stress release design directly deposited on an eco-flex substrate","authors":"Jonghyun Jeong, Gihak Kim, Jaewook Jeong","doi":"10.1088/2058-8585/accaf6","DOIUrl":"https://doi.org/10.1088/2058-8585/accaf6","url":null,"abstract":"In this paper, stretchable electrodes adopting a double stress release structure were fabricated and characterized on eco-flex substrates. First, the correlation between mechanical properties applying surface plasma treatment and stretching capability of stretchable silver electrodes directly deposited on eco-flex substrate was studied. The Young’s modulus values of the substrate and metal were extracted using the force-distance relation via atomic force microscopy employing Johnson–Kendall–Roberts model. It was found that, as the Young’s modulus increased with the increase of plasma treatment time, the stretching capability first improved; then, samples showed no improvement over long plasma treatment time. This indicates that there is an optimum plasma treatment time to simultaneously achieve high stretching capability and low initial resistance. Using the optimum time, stretchable silver electrodes adopting double stress release structure along lateral and vertical directions were fabricated and the high stretching capability of the silver electrodes was achieved up to tensile strain of about 160%, as was high stability of up to 1000 times the multi-cycling strain.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45645655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-04DOI: 10.1088/2058-8585/acca30
Kamalesh Tripathy, M. Bhattacharjee
The substrate plays an important role in flexible devices and sensors. In this direction, it is observed that elastomeric encapsulation assists the sensor system to deform successfully under stretching. The encapsulation not only makes it flexible but also protects it from environmental factors and mechanical damage. In this paper, a finite element method analysis is used to study the mechanical effects on the encapsulated system, which provides insight into the design of a stretchable substrate for flexible electronic systems. Here, a serpentine silver electrode is designed on a polyethylene terephthalate substrate, which is then encapsulated by polydimethylsiloxane. With the variation in the ratio of top-to-bottom encapsulation thickness i.e. T en1: T en2, the interfacial stress was studied. The mismatch in T en1 and T en2 may result in compressive bending strain, which can be avoided by making T en1 = T en2. It is observed from the simulation that, there is a spike in von-Mises stress at the interface of the substrate and the encapsulation when stretching mode deformation is applied. Also, this maximum stress varies with the variation in encapsulation thickness. For a range of total encapsulation thickness i.e. T EN = T en1 + T en2 = 30 μm to 100 μm, the optimum thickness is found to be 55 μm, for which the spike in interfacial von-Mises stress is minimum.
{"title":"Stretching mode deformation analysis for an elastomeric encapsulation-assisted stable flexible electronic substrate","authors":"Kamalesh Tripathy, M. Bhattacharjee","doi":"10.1088/2058-8585/acca30","DOIUrl":"https://doi.org/10.1088/2058-8585/acca30","url":null,"abstract":"The substrate plays an important role in flexible devices and sensors. In this direction, it is observed that elastomeric encapsulation assists the sensor system to deform successfully under stretching. The encapsulation not only makes it flexible but also protects it from environmental factors and mechanical damage. In this paper, a finite element method analysis is used to study the mechanical effects on the encapsulated system, which provides insight into the design of a stretchable substrate for flexible electronic systems. Here, a serpentine silver electrode is designed on a polyethylene terephthalate substrate, which is then encapsulated by polydimethylsiloxane. With the variation in the ratio of top-to-bottom encapsulation thickness i.e. T en1: T en2, the interfacial stress was studied. The mismatch in T en1 and T en2 may result in compressive bending strain, which can be avoided by making T en1 = T en2. It is observed from the simulation that, there is a spike in von-Mises stress at the interface of the substrate and the encapsulation when stretching mode deformation is applied. Also, this maximum stress varies with the variation in encapsulation thickness. For a range of total encapsulation thickness i.e. T EN = T en1 + T en2 = 30 μm to 100 μm, the optimum thickness is found to be 55 μm, for which the spike in interfacial von-Mises stress is minimum.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43350671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-03DOI: 10.1088/2058-8585/acc9d2
Kaitlin Wagner, Shan Zou, Y. Martínez-Rubí, A. Kell, Chantal Paquet, Benoît H. Lessard
Processing materials in electronics with non-toxic, green solvents can provide environmental benefits while reducing manufacturing health and safety challenges. Unfortunately, green solvents are often unable to provide comparable solubilizing characteristics and present challenges in printing and film formation compared to conventional organic solvents. Therefore, green materials are often developed in parallel to their processing method for successful implementation. In this study, we report on the use of a polyvinyl butyral (PVB) and ethanol solution as a replacement for poly (3-hexylthiophene-2,5-diyl) (P3HT) and chloroform and its’ first demonstration in boron nitride nanotube (BNNT) thin film interlayers for improved thermal and mechanical performance in silver microgrid transparent heaters. Using PVB/ethanol led to comparable thin films of BNNT, achieving a clear tube network formation across the substrate surface and resulting in near identical optical transparency and surface energy measurements compared to the P3HT/chloroform system. Silver microgrids printed on BNNT-coated polyethylene terephthalate (PET) with PVB as dispersant exhibited a similar conductive performance to the microgrids printed on BNNT-coated PET with P3HT, providing the same level of mechanical endurance and maintaining thermal performance metrics upon applied voltage. The PVB and ethanol system presents an exemplary green material combination for the novel deposition of BNNT thin film interlayers for integration into transparent heaters.
{"title":"Towards sustainable transparent flexible heaters: Integration of a BNNT interlayer using green solvent substitution","authors":"Kaitlin Wagner, Shan Zou, Y. Martínez-Rubí, A. Kell, Chantal Paquet, Benoît H. Lessard","doi":"10.1088/2058-8585/acc9d2","DOIUrl":"https://doi.org/10.1088/2058-8585/acc9d2","url":null,"abstract":"Processing materials in electronics with non-toxic, green solvents can provide environmental benefits while reducing manufacturing health and safety challenges. Unfortunately, green solvents are often unable to provide comparable solubilizing characteristics and present challenges in printing and film formation compared to conventional organic solvents. Therefore, green materials are often developed in parallel to their processing method for successful implementation. In this study, we report on the use of a polyvinyl butyral (PVB) and ethanol solution as a replacement for poly (3-hexylthiophene-2,5-diyl) (P3HT) and chloroform and its’ first demonstration in boron nitride nanotube (BNNT) thin film interlayers for improved thermal and mechanical performance in silver microgrid transparent heaters. Using PVB/ethanol led to comparable thin films of BNNT, achieving a clear tube network formation across the substrate surface and resulting in near identical optical transparency and surface energy measurements compared to the P3HT/chloroform system. Silver microgrids printed on BNNT-coated polyethylene terephthalate (PET) with PVB as dispersant exhibited a similar conductive performance to the microgrids printed on BNNT-coated PET with P3HT, providing the same level of mechanical endurance and maintaining thermal performance metrics upon applied voltage. The PVB and ethanol system presents an exemplary green material combination for the novel deposition of BNNT thin film interlayers for integration into transparent heaters.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46205503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-29DOI: 10.1088/2058-8585/acc879
Pranay Doshi, Hiu Yung Wong, Daniel H Gutierrez, Arlene Lopez, Dennis Nordlund, Ram P Gandhiraman
The proliferation of electronic devices has made electromagnetic interference (EMI) shielding an exponentially growing business. Regulatory requirements change constantly as new technologies continue to emerge. Innovations in materials and new advances in shielding implementation techniques are needed to pass regulatory compliance tests at an affordable cost. Here, we print various EMI shielding materials such as copper, silver and a composite of copper with Fe3O4 using plasma jet printing. Printing enables shields only a few microns thick capable of high shielding effectiveness. Copper’s EMI shielding performance is primarily contributed by reflection mechanism, as expected and this is known to cause secondary pollution. A Green Index for EMI shielding, given by the ratio of absorption and reflection contributions to shielding, indicates values lower than 0.1 for printed copper films.
{"title":"Printing of electromagnetic interference shielding materials","authors":"Pranay Doshi, Hiu Yung Wong, Daniel H Gutierrez, Arlene Lopez, Dennis Nordlund, Ram P Gandhiraman","doi":"10.1088/2058-8585/acc879","DOIUrl":"https://doi.org/10.1088/2058-8585/acc879","url":null,"abstract":"The proliferation of electronic devices has made electromagnetic interference (EMI) shielding an exponentially growing business. Regulatory requirements change constantly as new technologies continue to emerge. Innovations in materials and new advances in shielding implementation techniques are needed to pass regulatory compliance tests at an affordable cost. Here, we print various EMI shielding materials such as copper, silver and a composite of copper with Fe3O4 using plasma jet printing. Printing enables shields only a few microns thick capable of high shielding effectiveness. Copper’s EMI shielding performance is primarily contributed by reflection mechanism, as expected and this is known to cause secondary pollution. A Green Index for EMI shielding, given by the ratio of absorption and reflection contributions to shielding, indicates values lower than 0.1 for printed copper films.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44135346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-17DOI: 10.1088/2058-8585/acc540
B. Levit, P. Krebsbach, Chen Bar-Haim, G. Hernández-Sosa, Y. Hanein
Bio-impedance measurements are widely used to assess various physiological parameters. Contemporary skin electrodes for bio-impedance measurements are cumbersome and novel electrode designs are needed to allow fast and easy placement, long-term stability and user comfort. This investigation introduces dry, printed, bio-compatible electrode arrays, made of screen-printed carbon and inkjet-printed PEDOT:PSS that measure bio-impedance non-invasively and stably. Two contact impedance measurements yield the lowest normalized values of soft electrodes reported to date. Four contact bio-impedance measurements from the radial, ulnar, common carotid and superficial temporal arteries were performed, demonstrating the ability to capture blood pulsation in different areas with small form factor. Owing to the unique properties of the printed electrodes reported here, we were able to demonstrate for the first time blood pulsation in the face, continuous blood pulsation measurement during simultaneous muscle activation and signal stability over many hours.
{"title":"Printed soft skin electrodes for seamless bio-impedance measurements","authors":"B. Levit, P. Krebsbach, Chen Bar-Haim, G. Hernández-Sosa, Y. Hanein","doi":"10.1088/2058-8585/acc540","DOIUrl":"https://doi.org/10.1088/2058-8585/acc540","url":null,"abstract":"Bio-impedance measurements are widely used to assess various physiological parameters. Contemporary skin electrodes for bio-impedance measurements are cumbersome and novel electrode designs are needed to allow fast and easy placement, long-term stability and user comfort. This investigation introduces dry, printed, bio-compatible electrode arrays, made of screen-printed carbon and inkjet-printed PEDOT:PSS that measure bio-impedance non-invasively and stably. Two contact impedance measurements yield the lowest normalized values of soft electrodes reported to date. Four contact bio-impedance measurements from the radial, ulnar, common carotid and superficial temporal arteries were performed, demonstrating the ability to capture blood pulsation in different areas with small form factor. Owing to the unique properties of the printed electrodes reported here, we were able to demonstrate for the first time blood pulsation in the face, continuous blood pulsation measurement during simultaneous muscle activation and signal stability over many hours.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48447875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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