Pub Date : 2024-05-07DOI: 10.1038/s41528-024-00314-2
Chu Qin, Qingyin Sun, Yu Chen, Shah Fahad, Jiaxin Wu, Yuxuan Dong, Hongyu Yu, Min Wang
The flexibility and stability of transparent electrodes play a crucial role in the growing popularity of flexible devices, especially in potential wearable electronics. To date, various solution-coating techniques have been developed for fabricating silver nanowire (AgNW) flexible bioelectronics. However, achieving the orderly distributed patterns of AgNW without undesirable aggregations still poses a grand challenge. Here, an approach to realize regular patterned ultrathin AgNW networks on a freestanding electrospun PVDF-TrFE frame by evaporation-induced self-assembly is proposed. The patterning mechanism of evaporating AgNW colloidal suspension is investigated from experimental and theoretical analysis. The influence of evaporation-induced flow inside colloidal freestanding membranes on forming regular square hole-shaped arrays, selective deposition of AgNW, and aligning them along the artificial pinning array are addressed. Owing to the orderly arrangement of AgNW networks, the resultant flexible electrode achieves ultrathin thickness (about 5 μm), high optical transmittance (87.8%), and low sheet resistance (8.4 Ω·sq−1) with a relatively low dosage of AgNW (9 μg·cm−2). The electrode exhibits excellent durability during cyclic bending (50,000 times) and stretching (50% strain). The resistance remains virtually unchanged during 200 days in everyday environments. Furthermore, the excellent conformability and breathability of the flexible transparent electrode attached to the human skin demonstrates its potential application as an e-skin sensor. Our findings reliably urge a simple approach to underscore better outcomes with effective patterns by self-assembly of AgNW for highly conformal wearable electronics.
{"title":"Evaporation-induced self-assembled ultrathin AgNW networks for highly conformable wearable electronics","authors":"Chu Qin, Qingyin Sun, Yu Chen, Shah Fahad, Jiaxin Wu, Yuxuan Dong, Hongyu Yu, Min Wang","doi":"10.1038/s41528-024-00314-2","DOIUrl":"10.1038/s41528-024-00314-2","url":null,"abstract":"The flexibility and stability of transparent electrodes play a crucial role in the growing popularity of flexible devices, especially in potential wearable electronics. To date, various solution-coating techniques have been developed for fabricating silver nanowire (AgNW) flexible bioelectronics. However, achieving the orderly distributed patterns of AgNW without undesirable aggregations still poses a grand challenge. Here, an approach to realize regular patterned ultrathin AgNW networks on a freestanding electrospun PVDF-TrFE frame by evaporation-induced self-assembly is proposed. The patterning mechanism of evaporating AgNW colloidal suspension is investigated from experimental and theoretical analysis. The influence of evaporation-induced flow inside colloidal freestanding membranes on forming regular square hole-shaped arrays, selective deposition of AgNW, and aligning them along the artificial pinning array are addressed. Owing to the orderly arrangement of AgNW networks, the resultant flexible electrode achieves ultrathin thickness (about 5 μm), high optical transmittance (87.8%), and low sheet resistance (8.4 Ω·sq−1) with a relatively low dosage of AgNW (9 μg·cm−2). The electrode exhibits excellent durability during cyclic bending (50,000 times) and stretching (50% strain). The resistance remains virtually unchanged during 200 days in everyday environments. Furthermore, the excellent conformability and breathability of the flexible transparent electrode attached to the human skin demonstrates its potential application as an e-skin sensor. Our findings reliably urge a simple approach to underscore better outcomes with effective patterns by self-assembly of AgNW for highly conformal wearable electronics.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-9"},"PeriodicalIF":14.6,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00314-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140844987","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 : 2024-05-07DOI: 10.1038/s41528-024-00313-3
Hao Wang, Bin Sun, Shuzhi Sam Ge, Jie Su, Ming Liang Jin
The structure and mechanism of the human visual system contain rich treasures, and surprising effects can be achieved by simulating the human visual system. In this article, starting from the human visual system, we compare and discuss the discrepancies between the human visual system and traditional machine vision systems. Given the wide variety and large volume of visual information, the use of non-von Neumann structured, flexible neuromorphic vision sensors can effectively compensate for the limitations of traditional machine vision systems based on the von Neumann architecture. Firstly, this article addresses the emulation of retinal functionality and provides an overview of the principles and circuit implementation methods of non-von Neumann computing architectures. Secondly, in terms of mimicking the retinal surface structure, this article introduces the fabrication approach for flexible sensor arrays. Finally, this article analyzes the challenges currently faced by non-von Neumann flexible neuromorphic vision sensors and offers a perspective on their future development.
{"title":"On non-von Neumann flexible neuromorphic vision sensors","authors":"Hao Wang, Bin Sun, Shuzhi Sam Ge, Jie Su, Ming Liang Jin","doi":"10.1038/s41528-024-00313-3","DOIUrl":"10.1038/s41528-024-00313-3","url":null,"abstract":"The structure and mechanism of the human visual system contain rich treasures, and surprising effects can be achieved by simulating the human visual system. In this article, starting from the human visual system, we compare and discuss the discrepancies between the human visual system and traditional machine vision systems. Given the wide variety and large volume of visual information, the use of non-von Neumann structured, flexible neuromorphic vision sensors can effectively compensate for the limitations of traditional machine vision systems based on the von Neumann architecture. Firstly, this article addresses the emulation of retinal functionality and provides an overview of the principles and circuit implementation methods of non-von Neumann computing architectures. Secondly, in terms of mimicking the retinal surface structure, this article introduces the fabrication approach for flexible sensor arrays. Finally, this article analyzes the challenges currently faced by non-von Neumann flexible neuromorphic vision sensors and offers a perspective on their future development.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-26"},"PeriodicalIF":14.6,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00313-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140881232","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 : 2024-05-07DOI: 10.1038/s41528-024-00315-1
Chenyu Tang, Muzi Xu, Wentian Yi, Zibo Zhang, Edoardo Occhipinti, Chaoqun Dong, Dafydd Ravenscroft, Sung-Min Jung, Sanghyo Lee, Shuo Gao, Jong Min Kim, Luigi Giuseppe Occhipinti
This work introduces a silent speech interface (SSI), proposing a few-layer graphene (FLG) strain sensing mechanism based on thorough cracks and AI-based self-adaptation capabilities that overcome the limitations of state-of-the-art technologies by simultaneously achieving high accuracy, high computational efficiency, and fast decoding speed while maintaining excellent user comfort. We demonstrate its application in a biocompatible textile-integrated ultrasensitive strain sensor embedded into a smart choker, which conforms to the user’s throat. Thanks to the structure of ordered through cracks in the graphene-coated textile, the proposed strain gauge achieves a gauge factor of 317 with <5% strain, corresponding to a 420% improvement over existing textile strain sensors fabricated by printing and coating technologies reported to date. Its high sensitivity allows it to capture subtle throat movements, simplifying signal processing and enabling the use of a computationally efficient neural network. The resulting neural network, based on a one-dimensional convolutional model, reduces computational load by 90% while maintaining a remarkable 95.25% accuracy in speech decoding. The synergy in sensor design and neural network optimization offers a promising solution for practical, wearable SSI systems, paving the way for seamless, natural silent communication in diverse settings.
{"title":"Ultrasensitive textile strain sensors redefine wearable silent speech interfaces with high machine learning efficiency","authors":"Chenyu Tang, Muzi Xu, Wentian Yi, Zibo Zhang, Edoardo Occhipinti, Chaoqun Dong, Dafydd Ravenscroft, Sung-Min Jung, Sanghyo Lee, Shuo Gao, Jong Min Kim, Luigi Giuseppe Occhipinti","doi":"10.1038/s41528-024-00315-1","DOIUrl":"10.1038/s41528-024-00315-1","url":null,"abstract":"This work introduces a silent speech interface (SSI), proposing a few-layer graphene (FLG) strain sensing mechanism based on thorough cracks and AI-based self-adaptation capabilities that overcome the limitations of state-of-the-art technologies by simultaneously achieving high accuracy, high computational efficiency, and fast decoding speed while maintaining excellent user comfort. We demonstrate its application in a biocompatible textile-integrated ultrasensitive strain sensor embedded into a smart choker, which conforms to the user’s throat. Thanks to the structure of ordered through cracks in the graphene-coated textile, the proposed strain gauge achieves a gauge factor of 317 with <5% strain, corresponding to a 420% improvement over existing textile strain sensors fabricated by printing and coating technologies reported to date. Its high sensitivity allows it to capture subtle throat movements, simplifying signal processing and enabling the use of a computationally efficient neural network. The resulting neural network, based on a one-dimensional convolutional model, reduces computational load by 90% while maintaining a remarkable 95.25% accuracy in speech decoding. The synergy in sensor design and neural network optimization offers a promising solution for practical, wearable SSI systems, paving the way for seamless, natural silent communication in diverse settings.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-11"},"PeriodicalIF":14.6,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00315-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140844985","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}
In the era of ubiquitous computing with flourished visual displays in our surroundings, the application of haptic feedback technology still remains in its infancy. Bridging the gap between haptic technology and the real world to enable ambient haptic feedback on various physical surfaces is a grand challenge in the field of human-computer interaction. This paper presents the concept of an active electronic skin, characterized by three features: richness (multi-modal haptic stimuli), interactivity (bi-directional sensing and actuation capabilities), and invisibility (transparent, ultra-thin, flexible, and stretchable). By deploying this skin on physical surfaces, dynamic and versatile multi-modal haptic display, as well as tactile sensing, can be achieved. The potential applications of this skin include two categories: skin for the physical world (such as intelligent home, intelligent car, and intelligent museum), and skin for the digital world (such as haptic screen, wearable device, and bare-hand device). Furthermore, existing skin-based haptic display technologies including texture, thermal, and vibrotactile feedback are surveyed, as well as multidimensional tactile sensing techniques. By analyzing the gaps between current technologies and the goal of ambient haptics, future research topics are proposed, encompassing fundamental theoretical research on the physiological and psychological perception mechanisms of human skin, spatial-temporal registration among multimodal haptic stimuli, integration between sensing and actuation, and spatial-temporal registration between visual and haptic display. This concept of active electronic skin is promising for advancing the field of ambient haptics, enabling seamless integration of touch into our digital and physical surroundings.
{"title":"Active electronic skin: an interface towards ambient haptic feedback on physical surfaces","authors":"Yuan Guo, Yun Wang, Qianqian Tong, Boxue Shan, Liwen He, Yuru Zhang, Dangxiao Wang","doi":"10.1038/s41528-024-00311-5","DOIUrl":"10.1038/s41528-024-00311-5","url":null,"abstract":"In the era of ubiquitous computing with flourished visual displays in our surroundings, the application of haptic feedback technology still remains in its infancy. Bridging the gap between haptic technology and the real world to enable ambient haptic feedback on various physical surfaces is a grand challenge in the field of human-computer interaction. This paper presents the concept of an active electronic skin, characterized by three features: richness (multi-modal haptic stimuli), interactivity (bi-directional sensing and actuation capabilities), and invisibility (transparent, ultra-thin, flexible, and stretchable). By deploying this skin on physical surfaces, dynamic and versatile multi-modal haptic display, as well as tactile sensing, can be achieved. The potential applications of this skin include two categories: skin for the physical world (such as intelligent home, intelligent car, and intelligent museum), and skin for the digital world (such as haptic screen, wearable device, and bare-hand device). Furthermore, existing skin-based haptic display technologies including texture, thermal, and vibrotactile feedback are surveyed, as well as multidimensional tactile sensing techniques. By analyzing the gaps between current technologies and the goal of ambient haptics, future research topics are proposed, encompassing fundamental theoretical research on the physiological and psychological perception mechanisms of human skin, spatial-temporal registration among multimodal haptic stimuli, integration between sensing and actuation, and spatial-temporal registration between visual and haptic display. This concept of active electronic skin is promising for advancing the field of ambient haptics, enabling seamless integration of touch into our digital and physical surroundings.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-27"},"PeriodicalIF":14.6,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00311-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140820741","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 : 2024-04-16DOI: 10.1038/s41528-024-00307-1
Shirong Qiu, Bryan P. Y. Yan, Ni Zhao
Frequent and unobtrusive monitoring of cardiovascular conditions with consumer electronics is a widely pursued goal, since it provides the most economic and effective way of preventing and managing cardiovascular diseases (CVDs) ─ the leading causes of death worldwide. However, most current wearable and flexible devices can only support the measurement of one or two types of vital signs, such as heart rate and blood oxygen level, due to the lack of physiological models to link the measured signals to cardiovascular conditions. Here, we report a stroke-volume allocation (SVA) model to quantify the cushioning function of arteries and empower nearly all existing cardiac sensors with new functions, including arterial stiffness evaluation, dynamic blood pressure tracking and classification of CVD-related heart damage. Large-scale clinical data testing involving a hybrid dataset taken from 6 hospitals/research institutes (9 open databases and 4 self-built databases from 878 subjects in total) and diverse measurement approaches was carried out to validate the SVA model. The results show that the SVA-based parameters correlate well with the gold-standard measurements in arterial stiffness and blood pressure and outperform the commonly used vital sign (e.g., blood pressure) alone in detecting abnormalities in cardiovascular systems.
利用消费类电子产品对心血管状况进行频繁而不显眼的监测是人们普遍追求的目标，因为它是预防和控制心血管疾病（CVDs）--全球主要死亡原因--的最经济、最有效的方法。然而，由于缺乏将测量信号与心血管状况联系起来的生理模型，目前大多数可穿戴设备和柔性设备只能支持心率和血氧水平等一两种生命体征的测量。在此，我们报告了一种卒中量分配（SVA）模型，该模型可量化动脉的缓冲功能，并赋予几乎所有现有心脏传感器新的功能，包括动脉僵化评估、动态血压跟踪和心血管疾病相关心脏损伤分类。为了验证 SVA 模型，我们进行了大规模临床数据测试，其中包括来自 6 家医院/研究机构的混合数据集（9 个开放数据库和 4 个自建数据库，共计 878 名受试者）以及不同的测量方法。结果表明，基于 SVA 的参数与动脉僵化和血压的黄金标准测量值具有良好的相关性，在检测心血管系统异常方面优于常用的单独生命体征（如血压）。
{"title":"Stroke-volume-allocation model enabling wearable sensors for vascular age and cardiovascular disease assessment","authors":"Shirong Qiu, Bryan P. Y. Yan, Ni Zhao","doi":"10.1038/s41528-024-00307-1","DOIUrl":"10.1038/s41528-024-00307-1","url":null,"abstract":"Frequent and unobtrusive monitoring of cardiovascular conditions with consumer electronics is a widely pursued goal, since it provides the most economic and effective way of preventing and managing cardiovascular diseases (CVDs) ─ the leading causes of death worldwide. However, most current wearable and flexible devices can only support the measurement of one or two types of vital signs, such as heart rate and blood oxygen level, due to the lack of physiological models to link the measured signals to cardiovascular conditions. Here, we report a stroke-volume allocation (SVA) model to quantify the cushioning function of arteries and empower nearly all existing cardiac sensors with new functions, including arterial stiffness evaluation, dynamic blood pressure tracking and classification of CVD-related heart damage. Large-scale clinical data testing involving a hybrid dataset taken from 6 hospitals/research institutes (9 open databases and 4 self-built databases from 878 subjects in total) and diverse measurement approaches was carried out to validate the SVA model. The results show that the SVA-based parameters correlate well with the gold-standard measurements in arterial stiffness and blood pressure and outperform the commonly used vital sign (e.g., blood pressure) alone in detecting abnormalities in cardiovascular systems.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-10"},"PeriodicalIF":14.6,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00307-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140556422","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 : 2024-04-11DOI: 10.1038/s41528-024-00310-6
Yi Zhang, Changbo Liu, Ben Jia, Dongqin Ma, Xuecheng Tian, Yuanyuan Cui, Yuan Deng
Piezoelectric sensors whose sensing performances can be flexibly regulated hold significant promise for efficient signal-acquisition applications in the healthcare field. The existing methods for regulating the properties of polyvinylidene fluoride (PVDF) films mainly include material modification and structural design. Compared to material modification, which has a long test period and an unstable preparation process, structural design is a more efficient method. The irigami structure combined with compressive buckling can endow the flexible film with rich macrostructural features. Here, a method is fabricated to modulate the sensing performance by employing distinct 3D structures and encapsulation materials with varying Young’s moduli. The relationship among the aspect ratio (α), pattern factor (η), elastic modulus of encapsulation materials, and equivalent stiffness is obtained by finite element simulation, which provides theoretical guidance for the design of the 2D precursor and the selection of encapsulation materials. In the demonstration applications, the sensor accurately captures pulse waveforms in multiple parts of the human body and is employed for the pressure monitoring of different parts of the sole under various posture states. This method of structure design is efficient, and the preparation process is convenient, providing a strategy for the performance control of piezoelectric pressure sensors.
{"title":"Kirigami-inspired, three-dimensional piezoelectric pressure sensors assembled by compressive buckling","authors":"Yi Zhang, Changbo Liu, Ben Jia, Dongqin Ma, Xuecheng Tian, Yuanyuan Cui, Yuan Deng","doi":"10.1038/s41528-024-00310-6","DOIUrl":"10.1038/s41528-024-00310-6","url":null,"abstract":"Piezoelectric sensors whose sensing performances can be flexibly regulated hold significant promise for efficient signal-acquisition applications in the healthcare field. The existing methods for regulating the properties of polyvinylidene fluoride (PVDF) films mainly include material modification and structural design. Compared to material modification, which has a long test period and an unstable preparation process, structural design is a more efficient method. The irigami structure combined with compressive buckling can endow the flexible film with rich macrostructural features. Here, a method is fabricated to modulate the sensing performance by employing distinct 3D structures and encapsulation materials with varying Young’s moduli. The relationship among the aspect ratio (α), pattern factor (η), elastic modulus of encapsulation materials, and equivalent stiffness is obtained by finite element simulation, which provides theoretical guidance for the design of the 2D precursor and the selection of encapsulation materials. In the demonstration applications, the sensor accurately captures pulse waveforms in multiple parts of the human body and is employed for the pressure monitoring of different parts of the sole under various posture states. This method of structure design is efficient, and the preparation process is convenient, providing a strategy for the performance control of piezoelectric pressure sensors.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-11"},"PeriodicalIF":14.6,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00310-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140546899","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 : 2024-04-03DOI: 10.1038/s41528-024-00309-z
Hadi Moeinnia, Danielle Jaye Agron, Carl Ganzert, Loren Schubert, Woo Soo Kim
We present here a 3D-printed pressure mapping mat, equipped with customizable architecture sensors, that offers a cost-effective and adaptable solution, overcoming the size constraints and sensing accuracy issues commonly associated with existing commercial pressure mats across various fields, such as healthcare and sports applications. Leveraging a pillar-origami structure, the demonstrated sensor offers multifaceted stiffness properties, effectively filtering skin deformations and enabling capacitive pressure sensing. Notably, the sensor’s detection range can be finely tuned, spanning from 70 to 2500 kPa, with a sensitivity range between 0.01 kPa-1 and 0.0002 kPa-1, and an impressive response time of just 800 milliseconds. Furthermore, the inclusion of a modular sensor array enhances maintenance and allows for greater flexibility in shaping and enhancing the device’s resolution. This technology finds practical applications in wireless foot pressure mapping and sports protection pads, marking a significant milestone in the advancement of flexible and custom-shaped pressure sensor technology.
{"title":"Wireless pressure monitoring system utilizing a 3D-printed Origami pressure sensor array","authors":"Hadi Moeinnia, Danielle Jaye Agron, Carl Ganzert, Loren Schubert, Woo Soo Kim","doi":"10.1038/s41528-024-00309-z","DOIUrl":"10.1038/s41528-024-00309-z","url":null,"abstract":"We present here a 3D-printed pressure mapping mat, equipped with customizable architecture sensors, that offers a cost-effective and adaptable solution, overcoming the size constraints and sensing accuracy issues commonly associated with existing commercial pressure mats across various fields, such as healthcare and sports applications. Leveraging a pillar-origami structure, the demonstrated sensor offers multifaceted stiffness properties, effectively filtering skin deformations and enabling capacitive pressure sensing. Notably, the sensor’s detection range can be finely tuned, spanning from 70 to 2500 kPa, with a sensitivity range between 0.01 kPa-1 and 0.0002 kPa-1, and an impressive response time of just 800 milliseconds. Furthermore, the inclusion of a modular sensor array enhances maintenance and allows for greater flexibility in shaping and enhancing the device’s resolution. This technology finds practical applications in wireless foot pressure mapping and sports protection pads, marking a significant milestone in the advancement of flexible and custom-shaped pressure sensor technology.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-8"},"PeriodicalIF":14.6,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00309-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140343366","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 : 2024-04-03DOI: 10.1038/s41528-024-00308-0
Soon Joo Yoon, Jeongdae Ha, Hyeokjun Lee, Jin Tae Park, Bin Hyung Lee, Kyung-In Jang, Anna Yang, Yoon Kyeung Lee
The use of water-based chemistry in photolithography during semiconductor fabrication is desirable due to its cost-effectiveness and minimal environmental impact, especially considering the large scale of semiconductor production. Despite these benefits, limited research has reported successful demonstrations of water-based photopatterning, particularly for intrinsically water-soluble materials such as Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) due to significant challenges in achieving selective dissolution during the developing process. In this paper, we propose a method for the direct patterning of PEDOT:PSS in water by introducing an amphiphilic Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO, P123) block copolymer to the PEDOT:PSS film. The addition of the block copolymer enhances the stretchability of the composite film and reduces the hydrophilicity of the film surface, allowing for water absorption only after UV exposure through a photoinitiated reaction with benzophenone. We apply this technique to fabricate tactile and wearable biosensors, both of which benefit from the mechanical stretchability and transparency of PEDOT:PSS. Our method represents a promising solution for water-based photopatterning of hydrophilic materials, with potential for wider applications in semiconductor fabrication.
{"title":"Water-based direct photopatterning of stretchable PEDOT:PSS using amphiphilic block copolymers","authors":"Soon Joo Yoon, Jeongdae Ha, Hyeokjun Lee, Jin Tae Park, Bin Hyung Lee, Kyung-In Jang, Anna Yang, Yoon Kyeung Lee","doi":"10.1038/s41528-024-00308-0","DOIUrl":"10.1038/s41528-024-00308-0","url":null,"abstract":"The use of water-based chemistry in photolithography during semiconductor fabrication is desirable due to its cost-effectiveness and minimal environmental impact, especially considering the large scale of semiconductor production. Despite these benefits, limited research has reported successful demonstrations of water-based photopatterning, particularly for intrinsically water-soluble materials such as Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) due to significant challenges in achieving selective dissolution during the developing process. In this paper, we propose a method for the direct patterning of PEDOT:PSS in water by introducing an amphiphilic Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO, P123) block copolymer to the PEDOT:PSS film. The addition of the block copolymer enhances the stretchability of the composite film and reduces the hydrophilicity of the film surface, allowing for water absorption only after UV exposure through a photoinitiated reaction with benzophenone. We apply this technique to fabricate tactile and wearable biosensors, both of which benefit from the mechanical stretchability and transparency of PEDOT:PSS. Our method represents a promising solution for water-based photopatterning of hydrophilic materials, with potential for wider applications in semiconductor fabrication.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-10"},"PeriodicalIF":14.6,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00308-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140345846","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 : 2024-03-20DOI: 10.1038/s41528-024-00305-3
Wooyeon Kim, Jigeon Kim, Dayoung Kim, Bonkee Koo, Subin Yu, Yuelong Li, Younghoon Kim, Min Jae Ko
The electron transport layer (ETL) is a critical component in perovskite quantum dot (PQD) solar cells, significantly impacting their photovoltaic performance and stability. Low-temperature ETL deposition methods are especially desirable for fabricating flexible solar cells on polymer substrates. Herein, we propose a room-temperature-processed tin oxide (SnO2) ETL preparation method for flexible PQD solar cells. The process involves synthesizing highly crystalline SnO2 nanocrystals stabilized with organic ligands, spin-coating their dispersion, followed by UV irradiation. The energy level of SnO2 is controlled by doping gallium ions to reduce the energy level mismatch with the PQD. The proposed ETL-based CsPbI3-PQD solar cell achieves a power conversion efficiency (PCE) of 12.70%, the highest PCE among reported flexible quantum dot solar cells, maintaining 94% of the initial PCE after 500 bending tests. Consequently, we demonstrate that a systemically designed ETL enhances the photovoltaic performance and mechanical stability of flexible optoelectronic devices.
{"title":"Completely annealing-free flexible Perovskite quantum dot solar cells employing UV-sintered Ga-doped SnO2 electron transport layers","authors":"Wooyeon Kim, Jigeon Kim, Dayoung Kim, Bonkee Koo, Subin Yu, Yuelong Li, Younghoon Kim, Min Jae Ko","doi":"10.1038/s41528-024-00305-3","DOIUrl":"10.1038/s41528-024-00305-3","url":null,"abstract":"The electron transport layer (ETL) is a critical component in perovskite quantum dot (PQD) solar cells, significantly impacting their photovoltaic performance and stability. Low-temperature ETL deposition methods are especially desirable for fabricating flexible solar cells on polymer substrates. Herein, we propose a room-temperature-processed tin oxide (SnO2) ETL preparation method for flexible PQD solar cells. The process involves synthesizing highly crystalline SnO2 nanocrystals stabilized with organic ligands, spin-coating their dispersion, followed by UV irradiation. The energy level of SnO2 is controlled by doping gallium ions to reduce the energy level mismatch with the PQD. The proposed ETL-based CsPbI3-PQD solar cell achieves a power conversion efficiency (PCE) of 12.70%, the highest PCE among reported flexible quantum dot solar cells, maintaining 94% of the initial PCE after 500 bending tests. Consequently, we demonstrate that a systemically designed ETL enhances the photovoltaic performance and mechanical stability of flexible optoelectronic devices.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-11"},"PeriodicalIF":14.6,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00305-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140164505","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}
Wireless imaging, equipped with ultralow power wireless communications and energy harvesting (EH) capabilities, have emerged as battery-free and sustainable solutions. However, the challenge of implementing wireless colour imaging in wearable applications remains, primarily due to high power demands and the need to balance energy harvesting efficiency with device compactness. To address these issues, we propose a flexible and wearable battery-free backscatter wireless communication system specially designed for colour imaging. The system features a hybrid RF-solar EH array that efficiently harvests energy from both ambient RF and visible light energy, ensuring continuous operation in diverse environments. Moreover, flexible materials allow the working system to conform to the human body, ensuring comfort, user-friendliness, and safety. Furthermore, a compact design utilizing a shared-aperture antenna array for simultaneous wireless information and power transfer (SWIPT), coupled with an optically transparent stacked structure. This design not only optimizes space but also maintains the performance of both communication and EH processes. The proposed flexible and wearable systems for colour imaging would have potentially applications in environmental monitoring, object detection, and law enforcement recording. This approach demonstrates a sustainable and practical solution for the next generation of wearable, power-demanding devices.
{"title":"Flexible and wearable battery-free backscatter wireless communication system for colour imaging","authors":"Jun-Lin Zhan, Wei-Bing Lu, Cong Ding, Zhen Sun, Bu-Yun Yu, Lu Ju, Xin-Hua Liang, Zhao-Min Chen, Hao Chen, Yong-Hao Jia, Zhen-Guo Liu, Tie-Jun Cui","doi":"10.1038/s41528-024-00304-4","DOIUrl":"10.1038/s41528-024-00304-4","url":null,"abstract":"Wireless imaging, equipped with ultralow power wireless communications and energy harvesting (EH) capabilities, have emerged as battery-free and sustainable solutions. However, the challenge of implementing wireless colour imaging in wearable applications remains, primarily due to high power demands and the need to balance energy harvesting efficiency with device compactness. To address these issues, we propose a flexible and wearable battery-free backscatter wireless communication system specially designed for colour imaging. The system features a hybrid RF-solar EH array that efficiently harvests energy from both ambient RF and visible light energy, ensuring continuous operation in diverse environments. Moreover, flexible materials allow the working system to conform to the human body, ensuring comfort, user-friendliness, and safety. Furthermore, a compact design utilizing a shared-aperture antenna array for simultaneous wireless information and power transfer (SWIPT), coupled with an optically transparent stacked structure. This design not only optimizes space but also maintains the performance of both communication and EH processes. The proposed flexible and wearable systems for colour imaging would have potentially applications in environmental monitoring, object detection, and law enforcement recording. This approach demonstrates a sustainable and practical solution for the next generation of wearable, power-demanding devices.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-9"},"PeriodicalIF":14.6,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00304-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140135500","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}
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