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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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}
Pub Date : 2024-03-14DOI: 10.1038/s41528-024-00306-2
Keon-Woo Kim, Seong Ju Park, Su-Jeong Park, Inae Kim, Bomi Park, Se Hyun Kim, Unyong Jeong, Jin Kon Kim, Chanwoo Yang
Deformable and miniaturized energy storage devices are essential for powering soft electronics. Herein, we fabricate deformable micro supercapacitors (MSCs) based on eutectic gallium-indium liquid metal (EGaIn) current collectors with integrated graphene. The well-define interdigitated electrode patterning with controlled gap is successfully realized by using the laser ablation because of a strong laser absorption of graphene and EGaIn. By judicious control of gap size between neighboring interdigitated electrodes and mass loading of graphene, we achieve a high areal capacitance (1336 µF cm−2) with reliable rate performance. In addition, owing to the intrinsic liquid characteristics of EGaIn current collector, the areal capacitance of fabricated MSC retains 90% of original value even after repetitive folding and 20% stretching up to 1000 cycles. Finally, we successfully integrate deformable MSC with a commercial light-emitting diode to demonstrate the feasibility of MSC as a deformable power source. The fabricated MSCs operate stably under various mechanical deformations, including stretching, folding, twisting, and wrinkling.
{"title":"Deformable micro-supercapacitor fabricated via laser ablation patterning of Graphene/liquid metal","authors":"Keon-Woo Kim, Seong Ju Park, Su-Jeong Park, Inae Kim, Bomi Park, Se Hyun Kim, Unyong Jeong, Jin Kon Kim, Chanwoo Yang","doi":"10.1038/s41528-024-00306-2","DOIUrl":"10.1038/s41528-024-00306-2","url":null,"abstract":"Deformable and miniaturized energy storage devices are essential for powering soft electronics. Herein, we fabricate deformable micro supercapacitors (MSCs) based on eutectic gallium-indium liquid metal (EGaIn) current collectors with integrated graphene. The well-define interdigitated electrode patterning with controlled gap is successfully realized by using the laser ablation because of a strong laser absorption of graphene and EGaIn. By judicious control of gap size between neighboring interdigitated electrodes and mass loading of graphene, we achieve a high areal capacitance (1336 µF cm−2) with reliable rate performance. In addition, owing to the intrinsic liquid characteristics of EGaIn current collector, the areal capacitance of fabricated MSC retains 90% of original value even after repetitive folding and 20% stretching up to 1000 cycles. Finally, we successfully integrate deformable MSC with a commercial light-emitting diode to demonstrate the feasibility of MSC as a deformable power source. The fabricated MSCs operate stably under various mechanical deformations, including stretching, folding, twisting, and wrinkling.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":null,"pages":null},"PeriodicalIF":14.6,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00306-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140135499","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 : 2024-03-09DOI: 10.1038/s41528-024-00303-5
Minwoo Nam, Jaehyeock Chang, Hagseon Kim, Young Hyun Son, Yongmin Jeon, Jeong Hyun Kwon, Kyung Cheol Choi
Stretchable displays attract significant attention because of their potential applications in wearable electronics, smart textiles, and human-conformable devices. This paper introduces an electrically stable, mechanically ultra-robust, and water-resistant stretchable OLED display (SOLED) mounted on a stress-relief pillar platform. The SOLED is fabricated on a thin, transparent polyethylene terephthalate (PET) film using conventional vacuum evaporation, organic-inorganic hybrid thin film encapsulation (TFE), and a nonselective laser patterning process. This simple and efficient process yields an OLED display with exceptional stretchability, reaching up to 95% strain and outstanding durability, enduring 100,000 stretch-release cycles at 50% strain. Operational lifetime and water-resistant storage lifetime measurements confirm that the TFE provides effective protection even after the nonselective laser patterning process. A 3 × 3 array SOLED display module mounted on a stress-relief pillar platform is successfully implemented, marking the first case of water-resistant display array operation in the field of SOLEDs. This work aims to develop practical stretchable displays by offering a reliable fabrication method and device design for creating mechanically robust and adaptable displays, potentially paving the way for future advances in human-conformable electronics and other innovative applications.
{"title":"Highly reliable and stretchable OLEDs based on facile patterning method: toward stretchable organic optoelectronic devices","authors":"Minwoo Nam, Jaehyeock Chang, Hagseon Kim, Young Hyun Son, Yongmin Jeon, Jeong Hyun Kwon, Kyung Cheol Choi","doi":"10.1038/s41528-024-00303-5","DOIUrl":"10.1038/s41528-024-00303-5","url":null,"abstract":"Stretchable displays attract significant attention because of their potential applications in wearable electronics, smart textiles, and human-conformable devices. This paper introduces an electrically stable, mechanically ultra-robust, and water-resistant stretchable OLED display (SOLED) mounted on a stress-relief pillar platform. The SOLED is fabricated on a thin, transparent polyethylene terephthalate (PET) film using conventional vacuum evaporation, organic-inorganic hybrid thin film encapsulation (TFE), and a nonselective laser patterning process. This simple and efficient process yields an OLED display with exceptional stretchability, reaching up to 95% strain and outstanding durability, enduring 100,000 stretch-release cycles at 50% strain. Operational lifetime and water-resistant storage lifetime measurements confirm that the TFE provides effective protection even after the nonselective laser patterning process. A 3 × 3 array SOLED display module mounted on a stress-relief pillar platform is successfully implemented, marking the first case of water-resistant display array operation in the field of SOLEDs. This work aims to develop practical stretchable displays by offering a reliable fabrication method and device design for creating mechanically robust and adaptable displays, potentially paving the way for future advances in human-conformable electronics and other innovative applications.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":null,"pages":null},"PeriodicalIF":14.6,"publicationDate":"2024-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00303-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140096749","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}
Conductive patterned metal films bonded to compliant elastomeric substrates form meshes which enable flexible electronic interconnects for various applications. However, while bottom-up deposition of thin films by sputtering or growth is well-developed for rigid electronics, maintaining good electrical conductivity in sub-micron thin metal films upon large deformations or cyclic loading remains a significant challenge. Here, we propose a strategy to improve the electromechanical performance of nanometer-thin palladium films by in-situ synthesis of a conformal graphene coating using chemical vapor deposition (CVD). The uniform graphene coverage improves the thin film’s damage tolerance, electro-mechanical fatigue, and fracture toughness owing to the high stiffness of graphene and the conformal CVD-grown graphene-metal interface. Graphene-coated Pd thin film interconnects exhibit stable increase in electrical resistance even when strained beyond 60% and longer fatigue life up to a strain range of 20%. The effect of graphene is more significant for thinner films of < 300 nm, particularly at high strains. The experimental observations are well described by the thin film electro-fragmentation model and the Coffin-Manson relationship. These findings demonstrate the potential of CVD-grown graphene nanocomposite materials in improving the damage tolerance and electromechanical robustness of flexible electronics. The proposed approach offers opportunities for the development of reliable and high-performance ultra-conformable flexible electronic devices.
{"title":"Ultrathin damage-tolerant flexible metal interconnects reinforced by in-situ graphene synthesis","authors":"Kaihao Zhang, Mitisha Surana, Jad Yaacoub, Sameh Tawfick","doi":"10.1038/s41528-024-00300-8","DOIUrl":"10.1038/s41528-024-00300-8","url":null,"abstract":"Conductive patterned metal films bonded to compliant elastomeric substrates form meshes which enable flexible electronic interconnects for various applications. However, while bottom-up deposition of thin films by sputtering or growth is well-developed for rigid electronics, maintaining good electrical conductivity in sub-micron thin metal films upon large deformations or cyclic loading remains a significant challenge. Here, we propose a strategy to improve the electromechanical performance of nanometer-thin palladium films by in-situ synthesis of a conformal graphene coating using chemical vapor deposition (CVD). The uniform graphene coverage improves the thin film’s damage tolerance, electro-mechanical fatigue, and fracture toughness owing to the high stiffness of graphene and the conformal CVD-grown graphene-metal interface. Graphene-coated Pd thin film interconnects exhibit stable increase in electrical resistance even when strained beyond 60% and longer fatigue life up to a strain range of 20%. The effect of graphene is more significant for thinner films of < 300 nm, particularly at high strains. The experimental observations are well described by the thin film electro-fragmentation model and the Coffin-Manson relationship. These findings demonstrate the potential of CVD-grown graphene nanocomposite materials in improving the damage tolerance and electromechanical robustness of flexible electronics. The proposed approach offers opportunities for the development of reliable and high-performance ultra-conformable flexible electronic devices.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":null,"pages":null},"PeriodicalIF":14.6,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00300-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140066612","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 : 2024-03-07DOI: 10.1038/s41528-024-00302-6
Hwajoong Kim, Hyunbin Na, Seungbeom Noh, Shinwon Chang, Jinho Kim, Taejune Kong, Gyowook Shin, Chankyu Lee, Seonggyu Lee, Yong-Lae Park, Sehoon Oh, Jaehong Lee
For the accurate and continuous control of soft actuators in dynamic environments, the movements of the soft actuators must be monitored in real-time. To this end, various soft actuators capable of self-monitoring have been developed by separately integrating sensing devices into actuators. However, integrating such heterogeneous sensing components into soft actuators results in structural complexity, high manufacturing costs, and poor interfacial stability. Here, we report on intelligent pneumatic fiber-reinforced soft actuators with an inherent flexible proprioceptive sensor that uses only the essential components of typical fiber-reinforced soft actuators. The inherent flexible proprioceptive sensor is achieved by leveraging two parallel conductive microfibers around an elastomeric chamber of the soft actuator, which simultaneously acts as both a capacitive bending sensor and radial expansion limiting fibers of typical fiber-reinforced soft actuators. The proprioceptive soft actuator exhibits excellent mechanical actuation up to 240° bending motion and proprioceptive sensing performance with high sensitivity of 1.2 pF rad−1. Mathematical analysis and simulations of the soft actuator can effectively predict the bending actuation and capacitive responses against input pressures. We demonstrate that proprioceptive soft actuators can be used to construct a soft gripping system and prosthetic hand which express various hand gestures and perform dexterous manipulation with real-time proprioceptive sensing capability.
{"title":"Inherently integrated microfiber-based flexible proprioceptive sensor for feedback-controlled soft actuators","authors":"Hwajoong Kim, Hyunbin Na, Seungbeom Noh, Shinwon Chang, Jinho Kim, Taejune Kong, Gyowook Shin, Chankyu Lee, Seonggyu Lee, Yong-Lae Park, Sehoon Oh, Jaehong Lee","doi":"10.1038/s41528-024-00302-6","DOIUrl":"10.1038/s41528-024-00302-6","url":null,"abstract":"For the accurate and continuous control of soft actuators in dynamic environments, the movements of the soft actuators must be monitored in real-time. To this end, various soft actuators capable of self-monitoring have been developed by separately integrating sensing devices into actuators. However, integrating such heterogeneous sensing components into soft actuators results in structural complexity, high manufacturing costs, and poor interfacial stability. Here, we report on intelligent pneumatic fiber-reinforced soft actuators with an inherent flexible proprioceptive sensor that uses only the essential components of typical fiber-reinforced soft actuators. The inherent flexible proprioceptive sensor is achieved by leveraging two parallel conductive microfibers around an elastomeric chamber of the soft actuator, which simultaneously acts as both a capacitive bending sensor and radial expansion limiting fibers of typical fiber-reinforced soft actuators. The proprioceptive soft actuator exhibits excellent mechanical actuation up to 240° bending motion and proprioceptive sensing performance with high sensitivity of 1.2 pF rad−1. Mathematical analysis and simulations of the soft actuator can effectively predict the bending actuation and capacitive responses against input pressures. We demonstrate that proprioceptive soft actuators can be used to construct a soft gripping system and prosthetic hand which express various hand gestures and perform dexterous manipulation with real-time proprioceptive sensing capability.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":null,"pages":null},"PeriodicalIF":14.6,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00302-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140063865","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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