Shengrui Tian, Yilin Wang, Haitao Deng, Yan Wang, Xiaosheng Zhang
Electronic skin (E-skin) has gained significant attention due to its potential applications in the Internet of Things (IoT), artificial intelligence (AI), and flexible multi-sensing systems. Mimicking human skin, e-skin sensing devices can be employed in various scenarios. Among the most important sensing elements for tactile e-skin sensors are pressure and temperature sensors, which have increasingly garnered research interest over the past few decades. However, the design and fabrication of advanced pressure and temperature sensors can be challenging owing to complications such as signal interference, complex mechanism integration, and structural design issues. This review provides an overview of flexible pressure and temperature sensors used in e-skin, covering four main perspectives: material selection, mechanism integration, structural design, and manufacturing methods. The materials of different elements in the entire sensing system are comprehensively discussed, along with single and compound mechanisms of pressure and temperature sensing. Pressure and temperature sensors are divided into two types based on their electric output signals, which are exemplified in detail. The manufacturing methods used to fabricate these sensors, including printing methods, are outlined. Lastly, a summary of the future challenges faced by flexible pressure and temperature sensors used in e-skin is presented.
{"title":"Flexible pressure and temperature sensors towards e-skin: material, mechanism, structure and fabrication","authors":"Shengrui Tian, Yilin Wang, Haitao Deng, Yan Wang, Xiaosheng Zhang","doi":"10.20517/ss.2023.21","DOIUrl":"https://doi.org/10.20517/ss.2023.21","url":null,"abstract":"Electronic skin (E-skin) has gained significant attention due to its potential applications in the Internet of Things (IoT), artificial intelligence (AI), and flexible multi-sensing systems. Mimicking human skin, e-skin sensing devices can be employed in various scenarios. Among the most important sensing elements for tactile e-skin sensors are pressure and temperature sensors, which have increasingly garnered research interest over the past few decades. However, the design and fabrication of advanced pressure and temperature sensors can be challenging owing to complications such as signal interference, complex mechanism integration, and structural design issues. This review provides an overview of flexible pressure and temperature sensors used in e-skin, covering four main perspectives: material selection, mechanism integration, structural design, and manufacturing methods. The materials of different elements in the entire sensing system are comprehensively discussed, along with single and compound mechanisms of pressure and temperature sensing. Pressure and temperature sensors are divided into two types based on their electric output signals, which are exemplified in detail. The manufacturing methods used to fabricate these sensors, including printing methods, are outlined. Lastly, a summary of the future challenges faced by flexible pressure and temperature sensors used in e-skin is presented.","PeriodicalId":74837,"journal":{"name":"Soft science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45454468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thermoelectric materials and devices have garnered significant attention in recent years due to their potential for converting waste heat into usable electricity, opening new avenues for sustainable energy harvesting. As research in the field of thermoelectric materials and devices continues to grow, so does the need for efficient and scalable fabrication methods. Among various fabrication techniques, printing methods have emerged as promising approaches to producing thermoelectric materials and devices, offering advantages such as low cost, high throughput, and design flexibility. Here, we overview the recent advances in printing methods for the fabrication of thermoelectric materials and devices. We discuss the key principles, challenges, and opportunities associated with various printing techniques, including screen printing, inkjet printing, and 3D printing, with a focus on their applications in thermoelectric materials and devices. Furthermore, we highlight the progress made in optimizing the printing parameters, ink formulations, and post-processing methods to enhance the thermoelectric performance of printed materials and devices. Finally, we provide insights into the prospects and potential research directions in the field of printing methods for thermoelectric materials and devices. This review aims to provide a comprehensive overview of the state-of-the-art printing techniques for thermoelectric materials and devices and to serve as a reference for researchers and practitioners working in this rapidly growing field.
{"title":"Advances in printing techniques for thermoelectric materials and devices","authors":"M. Hong, Shuai Sun, Wan-Yu Lyu, Meng Li, Weidi Liu, Xiaolei Shi, Zhi-gang Chen","doi":"10.20517/ss.2023.20","DOIUrl":"https://doi.org/10.20517/ss.2023.20","url":null,"abstract":"Thermoelectric materials and devices have garnered significant attention in recent years due to their potential for converting waste heat into usable electricity, opening new avenues for sustainable energy harvesting. As research in the field of thermoelectric materials and devices continues to grow, so does the need for efficient and scalable fabrication methods. Among various fabrication techniques, printing methods have emerged as promising approaches to producing thermoelectric materials and devices, offering advantages such as low cost, high throughput, and design flexibility. Here, we overview the recent advances in printing methods for the fabrication of thermoelectric materials and devices. We discuss the key principles, challenges, and opportunities associated with various printing techniques, including screen printing, inkjet printing, and 3D printing, with a focus on their applications in thermoelectric materials and devices. Furthermore, we highlight the progress made in optimizing the printing parameters, ink formulations, and post-processing methods to enhance the thermoelectric performance of printed materials and devices. Finally, we provide insights into the prospects and potential research directions in the field of printing methods for thermoelectric materials and devices. This review aims to provide a comprehensive overview of the state-of-the-art printing techniques for thermoelectric materials and devices and to serve as a reference for researchers and practitioners working in this rapidly growing field.","PeriodicalId":74837,"journal":{"name":"Soft science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45493334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Huan Liu, Xiaodi Chen, Zihao Wang, Y. Liu, Cuiyuan Liang, Ming Zhu, Dianpeng Qi
Bioelectric signals reflect our daily physiological activities, which can be recorded in the form of electroencephalography, electrocardiography, electromyography, etc. The traditional Ag/AgCl wet electrode is the gold standard for clinical monitoring of bioelectrical signals at present, while complicated preparation and gel evaporation limit its long-term application. Therefore, it is meaningful to research dry electrodes without conductive paste or additional adhesives. Unfortunately, the high interface impedance between electrodes and skin is a fatal defect of dry electrodes, which leads to excessive noise levels and poor signal quality. Consequently, more efforts are required to achieve conformal contact between dry electrodes and skin to reduce the contact impedance. From this perspective, we review the recent progress in capacitive electrodes, invasive microneedle electrodes, and common-contact dry electrodes. Material selection and structural design to obtain conformal contact are highlighted. Finally, we propose the future development direction of dry electrodes.
{"title":"Development of soft dry electrodes: from materials to structure design","authors":"Huan Liu, Xiaodi Chen, Zihao Wang, Y. Liu, Cuiyuan Liang, Ming Zhu, Dianpeng Qi","doi":"10.20517/ss.2023.16","DOIUrl":"https://doi.org/10.20517/ss.2023.16","url":null,"abstract":"Bioelectric signals reflect our daily physiological activities, which can be recorded in the form of electroencephalography, electrocardiography, electromyography, etc. The traditional Ag/AgCl wet electrode is the gold standard for clinical monitoring of bioelectrical signals at present, while complicated preparation and gel evaporation limit its long-term application. Therefore, it is meaningful to research dry electrodes without conductive paste or additional adhesives. Unfortunately, the high interface impedance between electrodes and skin is a fatal defect of dry electrodes, which leads to excessive noise levels and poor signal quality. Consequently, more efforts are required to achieve conformal contact between dry electrodes and skin to reduce the contact impedance. From this perspective, we review the recent progress in capacitive electrodes, invasive microneedle electrodes, and common-contact dry electrodes. Material selection and structural design to obtain conformal contact are highlighted. Finally, we propose the future development direction of dry electrodes.","PeriodicalId":74837,"journal":{"name":"Soft science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45716877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Seonghyeon Nam, Chansul Park, Sung-Hyuk Sunwoo, Minseong Kim, Hyun-Yong Lee, Mincheol Lee, Dae‐Hyeong Kim
Soft conductive nanocomposites have introduced significant breakthroughs in bio-integrated electronics by mitigating the mechanical mismatch between the body and the device. Compared with conventional wearable sensors based on rigid electronic materials, the wearable sensors based on soft nanocomposites are advantageous to long-term and high-quality biosignal recordings. Materials used for the synthesis of the nanocomposites, especially nanofillers, are critical for determining the quality of recorded biosignals and the performance of the nanocomposites. In this review, we focus on recent advances in soft conductive nanocomposites, mainly on their electrical and mechanical properties according to the types of nanofillers, and present their applications to wearable biosignal recording devices. We have classified the nanofillers into four categories: carbon-based nanomaterials, conducting polymers, metal-based nanomaterials, and liquid metals. We then introduce the applications of nanocomposites as wearable sensors that record various biosignals, including electrophysiological, strain, pressure, and biochemical information. In conclusion, a brief outlook on the remaining challenges for future nanomaterial-based bioelectronics is provided.
{"title":"Soft conductive nanocomposites for recording biosignals on skin","authors":"Seonghyeon Nam, Chansul Park, Sung-Hyuk Sunwoo, Minseong Kim, Hyun-Yong Lee, Mincheol Lee, Dae‐Hyeong Kim","doi":"10.20517/ss.2023.19","DOIUrl":"https://doi.org/10.20517/ss.2023.19","url":null,"abstract":"Soft conductive nanocomposites have introduced significant breakthroughs in bio-integrated electronics by mitigating the mechanical mismatch between the body and the device. Compared with conventional wearable sensors based on rigid electronic materials, the wearable sensors based on soft nanocomposites are advantageous to long-term and high-quality biosignal recordings. Materials used for the synthesis of the nanocomposites, especially nanofillers, are critical for determining the quality of recorded biosignals and the performance of the nanocomposites. In this review, we focus on recent advances in soft conductive nanocomposites, mainly on their electrical and mechanical properties according to the types of nanofillers, and present their applications to wearable biosignal recording devices. We have classified the nanofillers into four categories: carbon-based nanomaterials, conducting polymers, metal-based nanomaterials, and liquid metals. We then introduce the applications of nanocomposites as wearable sensors that record various biosignals, including electrophysiological, strain, pressure, and biochemical information. In conclusion, a brief outlook on the remaining challenges for future nanomaterial-based bioelectronics is provided.","PeriodicalId":74837,"journal":{"name":"Soft science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47890926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Self-powered wearable Internet of Things (IoT) sensors have made a significant impact on human life and health in recent years. These sensors are known for their convenience, durability, affordability, and longevity, leading to substantial improvements in people’s lives. This review summarizes the development of self-powered wearable IoT sensors in recent years. Materials for self-powered wearable sensors are summarized and evaluated, including nanomaterials, flexible materials, and degradable materials. The working mode of self-powered wearable IoT sensors is analyzed, and the different principles of its physical sensing and chemical sensing are explained. Several common technologies for self-powered wearable IoT sensors are presented, such as triboelectric technology, piezoelectric technology, and machine learning. The applications of self-powered IoT wearable sensors in human-machine interfaces are reviewed. Its current shortcomings and prospects for its future development are also discussed. To conduct this review, a comprehensive literature search was performed using several electronic databases, resulting in the inclusion of 225 articles. The gathered data was extracted, synthesized, and analyzed using a thematic analysis approach. This review provides a comprehensive analysis and summary of its working mode, technologies, and applications and provides references and inspiration for related research in this field. Furthermore, this review also identifies the key directions and challenges for future research.
{"title":"Self-powered wearable IoT sensors as human-machine interfaces","authors":"Yuan Xi, Puchuan Tan, Zhou Li, Yubo Fan","doi":"10.20517/ss.2023.13","DOIUrl":"https://doi.org/10.20517/ss.2023.13","url":null,"abstract":"Self-powered wearable Internet of Things (IoT) sensors have made a significant impact on human life and health in recent years. These sensors are known for their convenience, durability, affordability, and longevity, leading to substantial improvements in people’s lives. This review summarizes the development of self-powered wearable IoT sensors in recent years. Materials for self-powered wearable sensors are summarized and evaluated, including nanomaterials, flexible materials, and degradable materials. The working mode of self-powered wearable IoT sensors is analyzed, and the different principles of its physical sensing and chemical sensing are explained. Several common technologies for self-powered wearable IoT sensors are presented, such as triboelectric technology, piezoelectric technology, and machine learning. The applications of self-powered IoT wearable sensors in human-machine interfaces are reviewed. Its current shortcomings and prospects for its future development are also discussed. To conduct this review, a comprehensive literature search was performed using several electronic databases, resulting in the inclusion of 225 articles. The gathered data was extracted, synthesized, and analyzed using a thematic analysis approach. This review provides a comprehensive analysis and summary of its working mode, technologies, and applications and provides references and inspiration for related research in this field. Furthermore, this review also identifies the key directions and challenges for future research.","PeriodicalId":74837,"journal":{"name":"Soft science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46694475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Tu, Ming Wang, Wenlong Li, Jiangtao Su, Yanzhen Li, Zhisheng Lv, Haicheng Li, Xue Feng, Xiaodong Chen
Multiple types of sensory information are detected and integrated to improve perceptual accuracy and sensitivity in biological cognition. However, current studies on electronic skin (e-skin) systems have mainly focused on the optimization of the modality-specific data acquisition and processing. Endowing e-skins with the abilities of multimodal sensing and even perception that can achieve high-level perception behaviors has been insufficiently explored. Moreover, the perception progress of multisensory e-skin systems is faced with challenges at both device and software levels. Here, we provide a perspective on the multisensory fusion of e-skins. The recent progress in e-skins realizing multimodal sensing is reviewed, followed by bottom-up and top-down multimodal perception. With the deepening understanding of neuroscience and the rapid advance of novel algorithms and devices, multimodal perception function becomes possible and will promote the development of highly intelligent e-skin systems.
{"title":"Electronic skins with multimodal sensing and perception","authors":"J. Tu, Ming Wang, Wenlong Li, Jiangtao Su, Yanzhen Li, Zhisheng Lv, Haicheng Li, Xue Feng, Xiaodong Chen","doi":"10.20517/ss.2023.15","DOIUrl":"https://doi.org/10.20517/ss.2023.15","url":null,"abstract":"Multiple types of sensory information are detected and integrated to improve perceptual accuracy and sensitivity in biological cognition. However, current studies on electronic skin (e-skin) systems have mainly focused on the optimization of the modality-specific data acquisition and processing. Endowing e-skins with the abilities of multimodal sensing and even perception that can achieve high-level perception behaviors has been insufficiently explored. Moreover, the perception progress of multisensory e-skin systems is faced with challenges at both device and software levels. Here, we provide a perspective on the multisensory fusion of e-skins. The recent progress in e-skins realizing multimodal sensing is reviewed, followed by bottom-up and top-down multimodal perception. With the deepening understanding of neuroscience and the rapid advance of novel algorithms and devices, multimodal perception function becomes possible and will promote the development of highly intelligent e-skin systems.","PeriodicalId":74837,"journal":{"name":"Soft science","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42201968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Human interaction with machines can be made easy, comfortable, and accessible by introducing user-friendly interfaces. In the case of wearable devices, their sensors and other interfacing elements are very well within the proximity of users. Since biopotential signals can be accessed from the surface of the human skin, users can have seamless interaction with wearable human-computer interactive devices. Rigid interfaces can hinder the user experience, and therefore, the need for soft biopotential interfaces is important. Imperceptible and unobtrusive soft biopotential interfaces will drastically enhance many aspects of human-computer interaction. This paper reviews the use of soft, flexible, and stretchable biopotential interfaces in wearable human-machine interactive devices. Additionally, attention is brought to the scope of other possible applications of soft biopotential interfaces in wearable devices.
{"title":"Prospects of soft biopotential interfaces for wearable human-machine interactive devices and applications","authors":"Pritish Nagwade, S. Parandeh, Sanghoon Lee","doi":"10.20517/ss.2023.12","DOIUrl":"https://doi.org/10.20517/ss.2023.12","url":null,"abstract":"Human interaction with machines can be made easy, comfortable, and accessible by introducing user-friendly interfaces. In the case of wearable devices, their sensors and other interfacing elements are very well within the proximity of users. Since biopotential signals can be accessed from the surface of the human skin, users can have seamless interaction with wearable human-computer interactive devices. Rigid interfaces can hinder the user experience, and therefore, the need for soft biopotential interfaces is important. Imperceptible and unobtrusive soft biopotential interfaces will drastically enhance many aspects of human-computer interaction. This paper reviews the use of soft, flexible, and stretchable biopotential interfaces in wearable human-machine interactive devices. Additionally, attention is brought to the scope of other possible applications of soft biopotential interfaces in wearable devices.","PeriodicalId":74837,"journal":{"name":"Soft science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42527638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Laser-induced direct graphene patterning: from formation mechanism to flexible applications","authors":"","doi":"10.20517/ss.2022.26","DOIUrl":"https://doi.org/10.20517/ss.2022.26","url":null,"abstract":"","PeriodicalId":74837,"journal":{"name":"Soft science","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67660235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Portable green energy out of the blue: hydrogel-based energy conversion devices","authors":"","doi":"10.20517/ss.2022.32","DOIUrl":"https://doi.org/10.20517/ss.2022.32","url":null,"abstract":"","PeriodicalId":74837,"journal":{"name":"Soft science","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67660341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}