With the increasing demand for wearable electronic products, there is a pressing need to develop electronic devices that seamlessly conform to the contours of the human body while delivering excellent performance and reliability. Traditional rigid electronic fabrication technologies fall short of meeting these requirements, necessitating the exploration of advanced flexible fabrication technologies that offer new possibilities for designing and fabricating flexible and stretchable electronic products, particularly in wearable devices. Over time, the continuous development of innovative fabrication techniques has ushered in significant improvements in the design freedom, lightweight, seamless integration, and multifunctionality of wearable electronics. Here, we provide a comprehensive overview of the advancements facilitated by advanced fabrication technology in wearable electronics. It specifically focuses on key fabrication methods, including printed electronics fabrication, soft transfer, 3D structure fabrication, and deformation fabrication. By highlighting these advancements, it sheds light on the challenges and prospects for further development in wearable electronics fabrication technologies. The introduction of advanced fabrication technologies has revolutionized the landscape of wearable/conformable electronics, expanding their application domains, streamlining system complexity associated with customization, manufacturing, and production, and opening up new avenues for innovation and development of body-conformable electronics.
{"title":"Revolutionizing wearable technology: advanced fabrication techniques for body-conformable electronics","authors":"Ruilai Wei, Haotian Li, Zhongming Chen, Qilin Hua, Guozhen Shen, Kai Jiang","doi":"10.1038/s41528-024-00370-8","DOIUrl":"10.1038/s41528-024-00370-8","url":null,"abstract":"With the increasing demand for wearable electronic products, there is a pressing need to develop electronic devices that seamlessly conform to the contours of the human body while delivering excellent performance and reliability. Traditional rigid electronic fabrication technologies fall short of meeting these requirements, necessitating the exploration of advanced flexible fabrication technologies that offer new possibilities for designing and fabricating flexible and stretchable electronic products, particularly in wearable devices. Over time, the continuous development of innovative fabrication techniques has ushered in significant improvements in the design freedom, lightweight, seamless integration, and multifunctionality of wearable electronics. Here, we provide a comprehensive overview of the advancements facilitated by advanced fabrication technology in wearable electronics. It specifically focuses on key fabrication methods, including printed electronics fabrication, soft transfer, 3D structure fabrication, and deformation fabrication. By highlighting these advancements, it sheds light on the challenges and prospects for further development in wearable electronics fabrication technologies. The introduction of advanced fabrication technologies has revolutionized the landscape of wearable/conformable electronics, expanding their application domains, streamlining system complexity associated with customization, manufacturing, and production, and opening up new avenues for innovation and development of body-conformable electronics.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-20"},"PeriodicalIF":12.3,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00370-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142762892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Flexible sensors are promising candidates in personalized healthcare, while desired sensors that allow implantation for biomedical applications with optimal sensing and favorable biological properties remain challenges. Here, a multifunctional hydrogel sensor was developed with gallic acid-modified chitosan (CSGA) and 3-carboxyphenylboronic acid-modified chitosan (CSPBA) by encapsulating Ag-decorated polydopamine (Ag@PDA) nanoparticles, namely Ag@PDA-(CSPBA/CSGA). The optimized hydrogel sensor showed desired sensitivity (gauge factor = 2.49), a rapid response/recovery time of 263 ms and good durability. Due to the presence of abundant reactive groups within Ag@PDA-(CSPBA/CSGA), the hydrogel sensor exhibited a comprehensive performance of self-healing, tissue adhesiveness, antioxidative activity, and antibacterial effects against Escherichia coli (92.76%) and Staphylococcus aureus (98.08%). Moreover, the hydrogel sensor could be utilized as a wound dressing, facilitating accelerated wound closure and tissue regeneration. Both subtle activities and large-scale movements could be monitored and distinguished by the hydrogel sensor. This study provides a promising epidermal sensor that offers multifunctionality for health monitoring and wound management.
{"title":"Ag@polydopamine-functionalized borate ester-linked chitosan hydrogel integrates monitoring with wound healing for epidermal sensor","authors":"Wei Shi, Hui Li, Chengsheng Xu, Gaoyi Wu, Jing Chen, Jinyong Zhang, Lixin Liang, Qingyang Wu, Yongsheng Liang, Guanglin Li, Wei Tang","doi":"10.1038/s41528-024-00366-4","DOIUrl":"10.1038/s41528-024-00366-4","url":null,"abstract":"Flexible sensors are promising candidates in personalized healthcare, while desired sensors that allow implantation for biomedical applications with optimal sensing and favorable biological properties remain challenges. Here, a multifunctional hydrogel sensor was developed with gallic acid-modified chitosan (CSGA) and 3-carboxyphenylboronic acid-modified chitosan (CSPBA) by encapsulating Ag-decorated polydopamine (Ag@PDA) nanoparticles, namely Ag@PDA-(CSPBA/CSGA). The optimized hydrogel sensor showed desired sensitivity (gauge factor = 2.49), a rapid response/recovery time of 263 ms and good durability. Due to the presence of abundant reactive groups within Ag@PDA-(CSPBA/CSGA), the hydrogel sensor exhibited a comprehensive performance of self-healing, tissue adhesiveness, antioxidative activity, and antibacterial effects against Escherichia coli (92.76%) and Staphylococcus aureus (98.08%). Moreover, the hydrogel sensor could be utilized as a wound dressing, facilitating accelerated wound closure and tissue regeneration. Both subtle activities and large-scale movements could be monitored and distinguished by the hydrogel sensor. This study provides a promising epidermal sensor that offers multifunctionality for health monitoring and wound management.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-12"},"PeriodicalIF":12.3,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00366-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142754185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-26DOI: 10.1038/s41528-024-00367-3
Hai-Tao Deng, Yi-Xuan Xia, Yu-Chi Liu, Beomjoon Kim, Xiao-Sheng Zhang
Multifunctional integration and heterogeneous surface integration are two crucial challenges in the in-depth use and development of triboelectric nanogenerators (TENGs) in the wearable electronic field. A promising solution is to develop stretchable TENGs (STENG), which have the potential for microenergy supply and self-powered sensing. The key challenge is to endow its functional components with good deformability and realize heterogeneous surface integration. Herein, we proposed a fully stretchable, surface adaptable TENG using stretchable micro-nano hierarchical friction interfaces. It integrated microenenrgy supply and multifunctional self-powered sensing (i.e., bend, force, and frequency sensing) abilities successfully. The highly-linear sensing abilities endows the STENG with a good biometric ability. As an application, a STENG array based-stretchable wearable keyboard was proposed. It identified dynamic keystroke motions of all users with a Support Vector Machine, with a high accuracy of 93.21%. Besides, the intruders who were not sampled were distinguished from users, with an accuracy of 81.50%.
{"title":"Stretchable nanogenerator with micro-nano hierarchical interfaces for self-powered biometric authentication","authors":"Hai-Tao Deng, Yi-Xuan Xia, Yu-Chi Liu, Beomjoon Kim, Xiao-Sheng Zhang","doi":"10.1038/s41528-024-00367-3","DOIUrl":"10.1038/s41528-024-00367-3","url":null,"abstract":"Multifunctional integration and heterogeneous surface integration are two crucial challenges in the in-depth use and development of triboelectric nanogenerators (TENGs) in the wearable electronic field. A promising solution is to develop stretchable TENGs (STENG), which have the potential for microenergy supply and self-powered sensing. The key challenge is to endow its functional components with good deformability and realize heterogeneous surface integration. Herein, we proposed a fully stretchable, surface adaptable TENG using stretchable micro-nano hierarchical friction interfaces. It integrated microenenrgy supply and multifunctional self-powered sensing (i.e., bend, force, and frequency sensing) abilities successfully. The highly-linear sensing abilities endows the STENG with a good biometric ability. As an application, a STENG array based-stretchable wearable keyboard was proposed. It identified dynamic keystroke motions of all users with a Support Vector Machine, with a high accuracy of 93.21%. Besides, the intruders who were not sampled were distinguished from users, with an accuracy of 81.50%.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-10"},"PeriodicalIF":12.3,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00367-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142712484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-23DOI: 10.1038/s41528-024-00371-7
Md Saifur Rahman, Simon A. Agnew, Samuel W. Ong, William J. Scheideler
Transparent conducting oxides (TCOs) are crucial for high-performance displays, solar cells, and wearable sensors. However, their high process temperatures and brittle nature have hindered their use in flexible electronics. In this paper, we overturn these limitations by harnessing Cabrera-Mott oxidation to fabricate large-area, two-dimensional (2D) transparent electrodes via liquid metal printing. Our robotic, vacuum-free process deposits ultrathin (2–10 nm) indium tin oxide (ITO) with exceptional flexibility, transparency (>95%) and conductivity (>1300 S/cm) by utilizing hypoeutectic In-Sn alloys to print at <140 °C. Detailed characterization reveals the efficacy of Sn-doping and high crystallinity with large, platelike grains. The ultrathin nature enhances bending strain tolerance and scratch resistance, exceeding durability of PEDOT and offering low contact impedance to skin comparable to Ag/AgCl. We implement 2D ITO in synchronous, multimodal electrocardiography (ECG) and pulse plethysmography (PPG) measurements. This order-of-magnitude improvement to printed TCOs could enable wearable biometrics and display-integrated sensors.
{"title":"Kinetic liquid metal synthesis of flexible 2D conductive oxides for multimodal wearable sensing","authors":"Md Saifur Rahman, Simon A. Agnew, Samuel W. Ong, William J. Scheideler","doi":"10.1038/s41528-024-00371-7","DOIUrl":"10.1038/s41528-024-00371-7","url":null,"abstract":"Transparent conducting oxides (TCOs) are crucial for high-performance displays, solar cells, and wearable sensors. However, their high process temperatures and brittle nature have hindered their use in flexible electronics. In this paper, we overturn these limitations by harnessing Cabrera-Mott oxidation to fabricate large-area, two-dimensional (2D) transparent electrodes via liquid metal printing. Our robotic, vacuum-free process deposits ultrathin (2–10 nm) indium tin oxide (ITO) with exceptional flexibility, transparency (>95%) and conductivity (>1300 S/cm) by utilizing hypoeutectic In-Sn alloys to print at <140 °C. Detailed characterization reveals the efficacy of Sn-doping and high crystallinity with large, platelike grains. The ultrathin nature enhances bending strain tolerance and scratch resistance, exceeding durability of PEDOT and offering low contact impedance to skin comparable to Ag/AgCl. We implement 2D ITO in synchronous, multimodal electrocardiography (ECG) and pulse plethysmography (PPG) measurements. This order-of-magnitude improvement to printed TCOs could enable wearable biometrics and display-integrated sensors.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-9"},"PeriodicalIF":12.3,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00371-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142694130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-22DOI: 10.1038/s41528-024-00368-2
Tran Duc Khanh, Jinho Joo, Jong-Woong Kim
In the burgeoning field of wearable electronics, flexible and durable conductors that can maintain consistent electrical properties under various conditions are critically needed. This research introduces a novel composite material comprising eutectic gallium-indium (EGaIn) and a polybutadiene-based urethane (PBU) specifically designed to address this challenge. EGaIn, renowned for its superior conductivity due to its liquid state at room temperature, is strategically combined with PBU, which offers inherent flexibility and remarkable self-healing capabilities derived from reversible Diels–Alder reactions. Additionally, the composite maintains exceptional electrical resistance stability, withstanding mechanical strains up to 135% without compromising performance. The material’s self-healing capability is attributed to the autonomous mending properties of EGaIn and the reversible Diels–Alder reactions in the PBU matrix. The result is an efficient restoration of the composite’s original properties upon incurring damage. Furthermore, the composite’s adaptability is showcased through its printability, allowing for precise patterning conducive to custom-designed wearable devices.
{"title":"Autonomous self-healing in a stretchable polybutadiene-based urethane and eutectic gallium indium conductive composite","authors":"Tran Duc Khanh, Jinho Joo, Jong-Woong Kim","doi":"10.1038/s41528-024-00368-2","DOIUrl":"10.1038/s41528-024-00368-2","url":null,"abstract":"In the burgeoning field of wearable electronics, flexible and durable conductors that can maintain consistent electrical properties under various conditions are critically needed. This research introduces a novel composite material comprising eutectic gallium-indium (EGaIn) and a polybutadiene-based urethane (PBU) specifically designed to address this challenge. EGaIn, renowned for its superior conductivity due to its liquid state at room temperature, is strategically combined with PBU, which offers inherent flexibility and remarkable self-healing capabilities derived from reversible Diels–Alder reactions. Additionally, the composite maintains exceptional electrical resistance stability, withstanding mechanical strains up to 135% without compromising performance. The material’s self-healing capability is attributed to the autonomous mending properties of EGaIn and the reversible Diels–Alder reactions in the PBU matrix. The result is an efficient restoration of the composite’s original properties upon incurring damage. Furthermore, the composite’s adaptability is showcased through its printability, allowing for precise patterning conducive to custom-designed wearable devices.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-15"},"PeriodicalIF":12.3,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00368-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142680013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-20DOI: 10.1038/s41528-024-00369-1
Sajjan Parajuli, Younsu Jung, Sagar Shrestha, Jinhwa Park, Chanyeop Ahn, Kiran Shrestha, Bijendra Bishow Maskey, Tae-Yeon Cho, Ji-Ho Eom, Changwoo Lee, Jeong-Taek Kong, Byung-Sung Kim, Taik-Min Lee, SoYoung Kim, Gyoujin Cho
Despite the roll-to-roll (R2R) gravure printing method emerging as an alternative sustainable technology for fabricating logic circuits based on p- and n-types of single-walled carbon nanotube thin film transistors (p,n-SWCNT-TFTs), the wide variation of large threshold voltage (Vth > ~8) in the R2R printed p,n-SWCNT-TFTs prevents the integration of complementary logic circuit. Here, the Vth variation of the p,n-SWCNT-TFTs was narrowed down by developing a method of using the first gravure roll with the minimized superposition error (< ±40 µm) of engraved registration marks and implementing the R2R doping process for tailoring the Vth using polymer-based p- and n-doping inks. Through those two methods, the R2R printed the p,n-SWCNT-TFTs was tailored to shift Vth to near ±2.7 V and reduce Vth variation to ±1.6 V while the noise margin was improved by 24% so that a large number of R2R printed logic gates could be integrated with clear logic levels at ±10 V of operation voltage. Based on the tailored p,n-SWCNT-TFTs, a fully R2R printed 4-bit arithmetic and logic unit was successfully demonstrated by integrating 156 p,n-SWCNT-TFTs.
尽管卷对卷（R2R）凹版印刷方法已成为基于 p 型和 n 型单壁碳纳米管薄膜晶体管（p,n-SWCNT-TFTs）制造逻辑电路的另一种可持续技术，但 R2R 印刷的 p,n-SWCNT-TFTs 的阈值电压（Vth > ~8）变化很大，阻碍了互补逻辑电路的集成。在此，我们开发了一种方法，即使用雕刻套准标记的叠加误差最小（< ±40 µm）的第一凹版辊，并使用聚合物基 p 和 n 掺杂油墨实施 R2R 掺杂工艺以定制 Vth，从而缩小了 p、n-SWCNT-TFT 的 Vth 变化。通过这两种方法，印刷在 p、n-SWCNT-TFT 上的 R2R 被定制为将 Vth 值移至接近 ±2.7 V，并将 Vth 值变化降低到 ±1.6 V，同时将噪声裕度提高了 24%，这样就可以集成大量 R2R 印刷逻辑门，并在 ±10 V 工作电压下具有清晰的逻辑电平。基于定制的 p、n-SWCNT-TFT，通过集成 156 个 p、n-SWCNT-TFT，成功演示了完全 R2R 印刷的 4 位算术和逻辑单元。
{"title":"Tailoring threshold voltage of R2R printed SWCNT thin film transistors for realizing 4 bit ALU","authors":"Sajjan Parajuli, Younsu Jung, Sagar Shrestha, Jinhwa Park, Chanyeop Ahn, Kiran Shrestha, Bijendra Bishow Maskey, Tae-Yeon Cho, Ji-Ho Eom, Changwoo Lee, Jeong-Taek Kong, Byung-Sung Kim, Taik-Min Lee, SoYoung Kim, Gyoujin Cho","doi":"10.1038/s41528-024-00369-1","DOIUrl":"10.1038/s41528-024-00369-1","url":null,"abstract":"Despite the roll-to-roll (R2R) gravure printing method emerging as an alternative sustainable technology for fabricating logic circuits based on p- and n-types of single-walled carbon nanotube thin film transistors (p,n-SWCNT-TFTs), the wide variation of large threshold voltage (Vth > ~8) in the R2R printed p,n-SWCNT-TFTs prevents the integration of complementary logic circuit. Here, the Vth variation of the p,n-SWCNT-TFTs was narrowed down by developing a method of using the first gravure roll with the minimized superposition error (< ±40 µm) of engraved registration marks and implementing the R2R doping process for tailoring the Vth using polymer-based p- and n-doping inks. Through those two methods, the R2R printed the p,n-SWCNT-TFTs was tailored to shift Vth to near ±2.7 V and reduce Vth variation to ±1.6 V while the noise margin was improved by 24% so that a large number of R2R printed logic gates could be integrated with clear logic levels at ±10 V of operation voltage. Based on the tailored p,n-SWCNT-TFTs, a fully R2R printed 4-bit arithmetic and logic unit was successfully demonstrated by integrating 156 p,n-SWCNT-TFTs.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-11"},"PeriodicalIF":12.3,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00369-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-14DOI: 10.1038/s41528-024-00364-6
Myunghwan Song, Junyoung Moon, Hyungseok Yong, Hyeonhui Song, Juneil Park, Jiwoong Hur, Dongchang Kim, Kyungtae Park, Sungwon Jung, Gyeongmo Kim, Sangeui Lee, Deokjae Heo, Kyunghwan Cha, Patrick T. J. Hwang, Jinkee Hong, Giuk Lee, Sangmin Lee
Electrical stimulation is effective for various therapeutic applications; however, to increase convenience, it is crucial to eliminate generators and batteries for wireless power transmission. This paper presents a full textile-based body-coupled electrical stimulation (BCES) system designed for wireless electrical stimulation using energy loss from electronic devices and static electricity from physical activity. We developed the BCES socks by knitting conductive threads to ensure stability and comfort. BCES socks generate electric fields ranging from tens to hundreds of millivolts per millimeter, which are sufficient to activate muscle fibers. Experimental and computational analyses confirmed the effective concentration of the electric fields. Human trials demonstrated significant improvements in exercise performance, with a 21.47% increase in calf raise frequency, an 11.97% increase in repetition count, and a 6.25% reduction in muscle fatigue. These results indicate the potential of BCES socks as a practical battery-free solution for enhancing muscle activity and reducing fatigue.
{"title":"Full textile-based body-coupled electrical stimulation for wireless, battery-free, and wearable bioelectronics","authors":"Myunghwan Song, Junyoung Moon, Hyungseok Yong, Hyeonhui Song, Juneil Park, Jiwoong Hur, Dongchang Kim, Kyungtae Park, Sungwon Jung, Gyeongmo Kim, Sangeui Lee, Deokjae Heo, Kyunghwan Cha, Patrick T. J. Hwang, Jinkee Hong, Giuk Lee, Sangmin Lee","doi":"10.1038/s41528-024-00364-6","DOIUrl":"10.1038/s41528-024-00364-6","url":null,"abstract":"Electrical stimulation is effective for various therapeutic applications; however, to increase convenience, it is crucial to eliminate generators and batteries for wireless power transmission. This paper presents a full textile-based body-coupled electrical stimulation (BCES) system designed for wireless electrical stimulation using energy loss from electronic devices and static electricity from physical activity. We developed the BCES socks by knitting conductive threads to ensure stability and comfort. BCES socks generate electric fields ranging from tens to hundreds of millivolts per millimeter, which are sufficient to activate muscle fibers. Experimental and computational analyses confirmed the effective concentration of the electric fields. Human trials demonstrated significant improvements in exercise performance, with a 21.47% increase in calf raise frequency, an 11.97% increase in repetition count, and a 6.25% reduction in muscle fatigue. These results indicate the potential of BCES socks as a practical battery-free solution for enhancing muscle activity and reducing fatigue.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-9"},"PeriodicalIF":12.3,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00364-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-08DOI: 10.1038/s41528-024-00363-7
Sangjun Kim, Jonathan Wells, Sarnab Bhattacharya, Hamsi Nathan, Jiaming He, Isabella Tubilla, Heeyong Huh, Pooja Kakani, Ali Farshkaran, Praveenkum Pasupathy, Jianshi Zhou, Emily Porter, Nathan Lazarus, Nanshu Lu
A wearable microgrid that centralizes and distributes harvested energy across different body regions can optimize power utilization and reduce overall battery weight. This setup underscores the importance of developing cable-free wireless power transfer (WPT) systems for mobile and portable devices to eliminate the risks posed by wired connections, especially in dynamic and hazardous environments. We introduce a thin, stretchable, and safe hand band capable of watt-level wireless charging through the widely adopted Qi protocol operating at 130 kHz. The implementation of non-adhesive fabric encapsulation serves to protect the 50-μm-thin spiral copper antenna from mechanical strain, ensuring an overall hand band stretchability of 50%. We also create a stretchable “Ferrofabric”, characterized by a magnetic permeability of 11.3 and a tensile modulus of 75.3 kPa, that provides magnetic shielding for the antenna without compromising wearability. The “Ferrofabric” improves the coil inductance but induces core loss in AC application. By fully understanding and managing loss mechanisms such as the skin effect, proximity effect, core loss, and joule heating, we achieve a wireless charging efficiency of 71% and power delivery of 3.81 W in the kHz frequency range. Our WPT hand band is unobstructive to hand motion and can charge a handheld smartphone as fast as a desktop charger or power a battery-free chest-laminated e-tattoo sensor, with well-managed thermal and electromagnetic safety. Through a holistic electromagnetic, structural, and thermal design, our device culminates in a safe, rugged, and versatile solution for wearable WPT systems.
{"title":"Unobstructive and safe-to-wear watt-level wireless charger","authors":"Sangjun Kim, Jonathan Wells, Sarnab Bhattacharya, Hamsi Nathan, Jiaming He, Isabella Tubilla, Heeyong Huh, Pooja Kakani, Ali Farshkaran, Praveenkum Pasupathy, Jianshi Zhou, Emily Porter, Nathan Lazarus, Nanshu Lu","doi":"10.1038/s41528-024-00363-7","DOIUrl":"10.1038/s41528-024-00363-7","url":null,"abstract":"A wearable microgrid that centralizes and distributes harvested energy across different body regions can optimize power utilization and reduce overall battery weight. This setup underscores the importance of developing cable-free wireless power transfer (WPT) systems for mobile and portable devices to eliminate the risks posed by wired connections, especially in dynamic and hazardous environments. We introduce a thin, stretchable, and safe hand band capable of watt-level wireless charging through the widely adopted Qi protocol operating at 130 kHz. The implementation of non-adhesive fabric encapsulation serves to protect the 50-μm-thin spiral copper antenna from mechanical strain, ensuring an overall hand band stretchability of 50%. We also create a stretchable “Ferrofabric”, characterized by a magnetic permeability of 11.3 and a tensile modulus of 75.3 kPa, that provides magnetic shielding for the antenna without compromising wearability. The “Ferrofabric” improves the coil inductance but induces core loss in AC application. By fully understanding and managing loss mechanisms such as the skin effect, proximity effect, core loss, and joule heating, we achieve a wireless charging efficiency of 71% and power delivery of 3.81 W in the kHz frequency range. Our WPT hand band is unobstructive to hand motion and can charge a handheld smartphone as fast as a desktop charger or power a battery-free chest-laminated e-tattoo sensor, with well-managed thermal and electromagnetic safety. Through a holistic electromagnetic, structural, and thermal design, our device culminates in a safe, rugged, and versatile solution for wearable WPT systems.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-15"},"PeriodicalIF":12.3,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00363-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142597367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-02DOI: 10.1038/s41528-024-00362-8
Bongho Jang, Junil Kim, Jieun Lee, Geuntae Park, Gyuwon Yang, Jaewon Jang, Hyuk-Jun Kwon
We developed high-performance flexible oxide thin-film transistors (TFTs) using SnO2 semiconductor and high-k ZrO2 dielectric, both formed through combustion-assisted sol-gel processes. This method involves the exothermic reaction of fuels and oxidizers to produce high-quality oxide films without extensive external heating. The combustion ZrO2 films were revealed to have an amorphous structure with a higher proportion of oxygen corresponding to the oxide network, which contributes to the low leakage current and frequency-independent dielectric properties. The ZrO2/SnO2 TFTs fabricated on flexible substrates using combustion synthesis exhibited excellent electrical characteristics, including a field-effect mobility of 26.16 cm2/Vs, a subthreshold swing of 0.125 V/dec, and an on/off current ratio of 1.13 × 106 at a low operating voltage of 3 V. Furthermore, we demonstrated flexible ZrO2/SnO2 TFTs with robust mechanical stability, capable of withstanding 5000 cycles of bending tests at a bending radius of 2.5 mm, achieved by scaling down the device dimensions.
{"title":"Combustion-assisted low-temperature ZrO2/SnO2 films for high-performance flexible thin film transistors","authors":"Bongho Jang, Junil Kim, Jieun Lee, Geuntae Park, Gyuwon Yang, Jaewon Jang, Hyuk-Jun Kwon","doi":"10.1038/s41528-024-00362-8","DOIUrl":"10.1038/s41528-024-00362-8","url":null,"abstract":"We developed high-performance flexible oxide thin-film transistors (TFTs) using SnO2 semiconductor and high-k ZrO2 dielectric, both formed through combustion-assisted sol-gel processes. This method involves the exothermic reaction of fuels and oxidizers to produce high-quality oxide films without extensive external heating. The combustion ZrO2 films were revealed to have an amorphous structure with a higher proportion of oxygen corresponding to the oxide network, which contributes to the low leakage current and frequency-independent dielectric properties. The ZrO2/SnO2 TFTs fabricated on flexible substrates using combustion synthesis exhibited excellent electrical characteristics, including a field-effect mobility of 26.16 cm2/Vs, a subthreshold swing of 0.125 V/dec, and an on/off current ratio of 1.13 × 106 at a low operating voltage of 3 V. Furthermore, we demonstrated flexible ZrO2/SnO2 TFTs with robust mechanical stability, capable of withstanding 5000 cycles of bending tests at a bending radius of 2.5 mm, achieved by scaling down the device dimensions.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-11"},"PeriodicalIF":12.3,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00362-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142563144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：