Pub Date : 2024-09-16DOI: 10.1038/s41528-024-00347-7
Ha Kyung Park, Kanghoon Yim, Jiyoon Lee, Yunae Cho, Inyoung Jeong, Donghyeop Shin, Jihye Gwak, Aron Walsh, Kihwan Kim, William Jo
Flexible and lightweight Cu(In,Ga)Se2 (CIGS) thin-film solar cells are promising for versatile applications, but there is limited understanding of stress-induced changes. In this study, the charge carrier generation and trapping behavior under mechanical stress was investigated using flexible CIGS thin-film solar cells with various alkali treatments. Surface current at the CIGS surface decreased by convex bending, which occurs less with the incorporation of alkali metals. The formation energy of the carrier generating defects increased in convex bending environments clarifying the degradation of the surface current. Moreover, alkali-related defects had lower formation energy than the intrinsic acceptors, mitigating current degradation in mechanical stress condition. The altered defect energy levels were attributed to the deformation of the crystal structure under bending states. This study provides insights into the mitigating of strain-induced charge degradation for enhancing the performance and robustness of flexible CIGS photovoltaic devices.
{"title":"Interplay between strain and charge in Cu(In,Ga)Se2 flexible photovoltaics","authors":"Ha Kyung Park, Kanghoon Yim, Jiyoon Lee, Yunae Cho, Inyoung Jeong, Donghyeop Shin, Jihye Gwak, Aron Walsh, Kihwan Kim, William Jo","doi":"10.1038/s41528-024-00347-7","DOIUrl":"https://doi.org/10.1038/s41528-024-00347-7","url":null,"abstract":"<p>Flexible and lightweight Cu(In,Ga)Se<sub>2</sub> (CIGS) thin-film solar cells are promising for versatile applications, but there is limited understanding of stress-induced changes. In this study, the charge carrier generation and trapping behavior under mechanical stress was investigated using flexible CIGS thin-film solar cells with various alkali treatments. Surface current at the CIGS surface decreased by convex bending, which occurs less with the incorporation of alkali metals. The formation energy of the carrier generating defects increased in convex bending environments clarifying the degradation of the surface current. Moreover, alkali-related defects had lower formation energy than the intrinsic acceptors, mitigating current degradation in mechanical stress condition. The altered defect energy levels were attributed to the deformation of the crystal structure under bending states. This study provides insights into the mitigating of strain-induced charge degradation for enhancing the performance and robustness of flexible CIGS photovoltaic devices.</p>","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":null,"pages":null},"PeriodicalIF":14.6,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142235096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-10DOI: 10.1038/s41528-024-00343-x
Ajay Nimbalkar, Aqsa Irfan, Min Chul Suh
Stretchable organic light-emitting diodes (SOLEDs) have been the challenging class of OLEDs as they have limited processability to fabricate a design that can withstand external deformation. Herein, we demonstrated the highly efficient top-emitting geometrical stretchable OLED (GSOLED) by incorporating the prestretched elastomer with optical adhesive film. The experimental and theoretical characterizations verified the enhancement of device efficiencies with the light extraction phenomenon brought by nanowavy corrugated structures. Furthermore, GSOLED shows stability in stretchable conditions and displays narrower emission spectrum with improved color purity. The full width at half maximum (FWHM) of 21 nm shows narrowband emission with a high current efficiency and EQE of 221 cd A−1 and 39.50%. This work marks a significant step forward, providing unprecedented insights into the factors influencing device performance in current and future material systems for stretchable organic light-emitting diodes.
{"title":"Creating highly efficient stretchable OLEDs with nanowavy structures for angle-independent narrow band emission","authors":"Ajay Nimbalkar, Aqsa Irfan, Min Chul Suh","doi":"10.1038/s41528-024-00343-x","DOIUrl":"10.1038/s41528-024-00343-x","url":null,"abstract":"Stretchable organic light-emitting diodes (SOLEDs) have been the challenging class of OLEDs as they have limited processability to fabricate a design that can withstand external deformation. Herein, we demonstrated the highly efficient top-emitting geometrical stretchable OLED (GSOLED) by incorporating the prestretched elastomer with optical adhesive film. The experimental and theoretical characterizations verified the enhancement of device efficiencies with the light extraction phenomenon brought by nanowavy corrugated structures. Furthermore, GSOLED shows stability in stretchable conditions and displays narrower emission spectrum with improved color purity. The full width at half maximum (FWHM) of 21 nm shows narrowband emission with a high current efficiency and EQE of 221 cd A−1 and 39.50%. This work marks a significant step forward, providing unprecedented insights into the factors influencing device performance in current and future material systems for stretchable organic light-emitting diodes.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":null,"pages":null},"PeriodicalIF":12.3,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00343-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142160360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Flexible devices, such as soft bioelectronics and stretchable supercapacitors, have their practical performance limited by electrodes which are desired to have high conductivity and capacitance, outstanding mechanical flexibility and strength, great electrochemical stability, and good biocompatibility. Here, we report a simple and efficient method to synthesize a nanostructured conductive hydrogel to meet such criteria. Specifically, templated by a hyperconnective nanofibrous network from aramid hydrogels, the conducting polymer, polypyrrole, assembles conformally onto nanofibers through in-situ polymerization, generating continuous nanostructured conductive pathways. The resulting conductive hydrogel shows superior conductivity (72 S cm−1) and fracture strength (27.2 MPa). Supercapacitor electrodes utilizing this hydrogel exhibit high specific capacitance (240 F g−1) and cyclic stability. Furthermore, bioelectrodes of patterned hydrogels provide favorable bioelectronic interfaces, allowing high-quality electrophysiological recording and stimulation in physiological environments. These high-performance electrodes are readily scalable to applications of energy and power systems, healthcare and medical technologies, smart textiles, and so forth.
软生物电子学和可拉伸超级电容器等柔性设备的实用性能受到电极的限制，电极需要具有高导电性和电容、出色的机械柔韧性和强度、高电化学稳定性和良好的生物相容性。在此，我们报告了一种简单高效的方法来合成符合上述标准的纳米结构导电水凝胶。具体来说，以芳纶水凝胶的超连接纳米纤维网为模板，导电聚合物聚吡咯通过原位聚合作用顺应性地组装到纳米纤维上，产生连续的纳米结构导电通路。由此产生的导电水凝胶显示出卓越的导电性（72 S cm-1）和断裂强度（27.2 兆帕）。使用这种水凝胶的超级电容器电极具有很高的比电容（240 F g-1）和循环稳定性。此外，图案化水凝胶生物电极提供了有利的生物电子界面，可在生理环境中进行高质量的电生理记录和刺激。这些高性能电极可随时扩展到能源和电力系统、保健和医疗技术、智能纺织品等应用领域。
{"title":"Strong and high-conductivity hydrogels with all-polymer nanofibrous networks for applications as high-capacitance flexible electrodes","authors":"Huimin He, Yaqing Chen, Aoyang Pu, Li Wang, Wenxiu Li, Xiaoyu Zhou, Chuyang Y. Tang, Kiwon Ban, Mengsu Yang, Lizhi Xu","doi":"10.1038/s41528-024-00346-8","DOIUrl":"10.1038/s41528-024-00346-8","url":null,"abstract":"Flexible devices, such as soft bioelectronics and stretchable supercapacitors, have their practical performance limited by electrodes which are desired to have high conductivity and capacitance, outstanding mechanical flexibility and strength, great electrochemical stability, and good biocompatibility. Here, we report a simple and efficient method to synthesize a nanostructured conductive hydrogel to meet such criteria. Specifically, templated by a hyperconnective nanofibrous network from aramid hydrogels, the conducting polymer, polypyrrole, assembles conformally onto nanofibers through in-situ polymerization, generating continuous nanostructured conductive pathways. The resulting conductive hydrogel shows superior conductivity (72 S cm−1) and fracture strength (27.2 MPa). Supercapacitor electrodes utilizing this hydrogel exhibit high specific capacitance (240 F g−1) and cyclic stability. Furthermore, bioelectrodes of patterned hydrogels provide favorable bioelectronic interfaces, allowing high-quality electrophysiological recording and stimulation in physiological environments. These high-performance electrodes are readily scalable to applications of energy and power systems, healthcare and medical technologies, smart textiles, and so forth.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":null,"pages":null},"PeriodicalIF":12.3,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00346-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142160309","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 : 2024-09-05DOI: 10.1038/s41528-024-00339-7
Chaoyang Kuang, Shangzhi Chen, Mingna Liao, Aiman Rahmanudin, Debashree Banerjee, Jesper Edberg, Klas Tybrandt, Dan Zhao, Magnus P. Jonsson
Materials that provide dynamically tunable infrared (IR) response are important for many applications, including active camouflage and thermal management. However, current IR-tunable systems often exhibit limitations in mechanical properties or practicality of their tuning modalities, or require complex and costly fabrication methods. An additional challenge relates to providing compatibility between different spectral channels, such as allowing an object to be reversibly concealed in the IR without making it appear in the visible range. Here, we demonstrate that conducting polymer-cellulose papers, fabricated through a simple and cheap approach, can overcome such challenges. The papers exhibit IR properties that can be electrochemically tuned with large modulation (absolute emissivity modulation of 0.4) while maintaining largely constant response in the visible range. Owing to high ionic and electrical conductivity, the tuning of the top surface can be performed electrochemically from the other side of the paper even at tens of micrometer thicknesses, removing the need for overlaying electrode and electrolyte in the optical beam path. These features enabled a series of electrically tunable IR devices, where we focus on demonstrating dynamic radiative coolers, thermal camouflage, anti-counterfeiting tags, and grayscale IR displays. The conducting polymer-cellulose papers are sustainable, cheap, flexible and mechanically robust, providing a versatile materials platform for active and adaptive IR optoelectronic devices.
{"title":"Electrically tunable infrared optics enabled by flexible ion-permeable conducting polymer-cellulose paper","authors":"Chaoyang Kuang, Shangzhi Chen, Mingna Liao, Aiman Rahmanudin, Debashree Banerjee, Jesper Edberg, Klas Tybrandt, Dan Zhao, Magnus P. Jonsson","doi":"10.1038/s41528-024-00339-7","DOIUrl":"10.1038/s41528-024-00339-7","url":null,"abstract":"Materials that provide dynamically tunable infrared (IR) response are important for many applications, including active camouflage and thermal management. However, current IR-tunable systems often exhibit limitations in mechanical properties or practicality of their tuning modalities, or require complex and costly fabrication methods. An additional challenge relates to providing compatibility between different spectral channels, such as allowing an object to be reversibly concealed in the IR without making it appear in the visible range. Here, we demonstrate that conducting polymer-cellulose papers, fabricated through a simple and cheap approach, can overcome such challenges. The papers exhibit IR properties that can be electrochemically tuned with large modulation (absolute emissivity modulation of 0.4) while maintaining largely constant response in the visible range. Owing to high ionic and electrical conductivity, the tuning of the top surface can be performed electrochemically from the other side of the paper even at tens of micrometer thicknesses, removing the need for overlaying electrode and electrolyte in the optical beam path. These features enabled a series of electrically tunable IR devices, where we focus on demonstrating dynamic radiative coolers, thermal camouflage, anti-counterfeiting tags, and grayscale IR displays. The conducting polymer-cellulose papers are sustainable, cheap, flexible and mechanically robust, providing a versatile materials platform for active and adaptive IR optoelectronic devices.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":null,"pages":null},"PeriodicalIF":12.3,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00339-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142142695","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 : 2024-08-30DOI: 10.1038/s41528-024-00340-0
Hansel Alex Hobbie, James L. Doherty, Brittany N. Smith, Paolo Maccarini, Aaron D. Franklin
With the growth of additive manufacturing (AM), there has been increasing demand for fabricating conformal electronics that directly integrate with larger components to enable unique functionality. However, fabrication of conformal electronics is challenging because devices must merge with host substrates regardless of curvilinearity, topography, or substrate material. In this work, we employ aerosol jet (AJ) printing, an AM method for jet printing electronics using ink-based materials, and a custom-made lathe mechanism for mounting flexible substrates and 3D objects on a rotating axis. Using this method of lathe-based AJ printing, conformal electronics are printed around the circumference of rotational bodies with 3D curvilinear surfaces through cylindrical-coordinate motion. We characterize the diverse capabilities of lathe AJ (LAJ) printing and demonstrate flexible conformal electronics including multilayer carbon nanotube transistors. Lastly, a graphene sensor is conformally printed on an inflated catheter balloon for temperature and inflation monitoring, thus highlighting the versatilities of LAJ printing.
随着增材制造（AM）技术的发展，人们对制造保形电子元件的需求日益增长，这种电子元件可直接与较大的元件集成，从而实现独特的功能。然而，保形电子器件的制造具有挑战性，因为器件必须与主机基底融合，而不受曲率、地形或基底材料的影响。在这项工作中，我们采用了气溶胶喷射（AJ）打印技术（一种使用墨基材料喷射打印电子元件的 AM 方法）和定制的车床装置，用于在旋转轴上安装柔性基底和三维物体。使用这种基于车床的 AJ 打印方法，可以通过圆柱坐标运动在旋转体的圆周上打印出具有三维曲线表面的保形电子器件。我们描述了车床 AJ（LAJ）打印的各种能力，并展示了包括多层碳纳米管晶体管在内的柔性保形电子器件。最后，我们在充气导管球囊上保形打印了一个石墨烯传感器，用于温度和充气监测，从而突出了 LAJ 打印的多功能性。
{"title":"Conformal printed electronics on flexible substrates and inflatable catheters using lathe-based aerosol jet printing","authors":"Hansel Alex Hobbie, James L. Doherty, Brittany N. Smith, Paolo Maccarini, Aaron D. Franklin","doi":"10.1038/s41528-024-00340-0","DOIUrl":"10.1038/s41528-024-00340-0","url":null,"abstract":"With the growth of additive manufacturing (AM), there has been increasing demand for fabricating conformal electronics that directly integrate with larger components to enable unique functionality. However, fabrication of conformal electronics is challenging because devices must merge with host substrates regardless of curvilinearity, topography, or substrate material. In this work, we employ aerosol jet (AJ) printing, an AM method for jet printing electronics using ink-based materials, and a custom-made lathe mechanism for mounting flexible substrates and 3D objects on a rotating axis. Using this method of lathe-based AJ printing, conformal electronics are printed around the circumference of rotational bodies with 3D curvilinear surfaces through cylindrical-coordinate motion. We characterize the diverse capabilities of lathe AJ (LAJ) printing and demonstrate flexible conformal electronics including multilayer carbon nanotube transistors. Lastly, a graphene sensor is conformally printed on an inflated catheter balloon for temperature and inflation monitoring, thus highlighting the versatilities of LAJ printing.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":null,"pages":null},"PeriodicalIF":12.3,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00340-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142100547","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 : 2024-08-29DOI: 10.1038/s41528-024-00341-z
Hongbin An, Xian Wang, Zhikang Liao, Liang Zhang, Hui Zhao, Yingyun Yang, Jizhou Song, Yinji Ma
Twenty-four hours continuous intraocular pressure (IOP) monitoring is beneficial for glaucoma care. Contact lens sensors using LC technology can achieve non-invasive continuous IOP measuring around the clock and are relatively simple in principle and structure, thus dominating the mainstream. Among them, stretchable inductive LC contact lens sensors constructed with liquid metal have advantages in signal quality as well as wearing comfort, but currently its sensitivity is slightly insufficient. Here, we propose an LC sensor that constructed with liquid metal to form the stretchable inductance and capacitance further. The capacitive plate and inductive coil can response to IOP changes simultaneously, thus able to enhance the sensitivity in principle. We modeled the sensing mechanism and conducted design, fabrication, as well as various tests. The device exhibits good characteristics, including reliability, good signal quality, etc. Especially, it has a threefold increase in sensitivity, exceeding the current state-of-the-art contact lens sensors.
{"title":"LC contact lens sensor for ultrasensitive intraocular pressure monitoring","authors":"Hongbin An, Xian Wang, Zhikang Liao, Liang Zhang, Hui Zhao, Yingyun Yang, Jizhou Song, Yinji Ma","doi":"10.1038/s41528-024-00341-z","DOIUrl":"10.1038/s41528-024-00341-z","url":null,"abstract":"Twenty-four hours continuous intraocular pressure (IOP) monitoring is beneficial for glaucoma care. Contact lens sensors using LC technology can achieve non-invasive continuous IOP measuring around the clock and are relatively simple in principle and structure, thus dominating the mainstream. Among them, stretchable inductive LC contact lens sensors constructed with liquid metal have advantages in signal quality as well as wearing comfort, but currently its sensitivity is slightly insufficient. Here, we propose an LC sensor that constructed with liquid metal to form the stretchable inductance and capacitance further. The capacitive plate and inductive coil can response to IOP changes simultaneously, thus able to enhance the sensitivity in principle. We modeled the sensing mechanism and conducted design, fabrication, as well as various tests. The device exhibits good characteristics, including reliability, good signal quality, etc. Especially, it has a threefold increase in sensitivity, exceeding the current state-of-the-art contact lens sensors.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":null,"pages":null},"PeriodicalIF":12.3,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00341-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142100556","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}
Fabricating high-conductive composites and constructing highly conductive networks are crucial for high-performance electrothermal film. In this study, an Ag nanowires/graphene (Ag/G) composite synthesized by liquid-phase exfoliation and in-situ photoreduction is mixed with carbon black (CB) to form a composite conductive ink, and a CB/Ag/G composite electrothermal film with a point-line-plane three-dimensional microstructure is obtained via blade coating process. Both the addition of Ag nanowires and a subsequent compression rolling treatment induce the establishment of the effective conductive network in the film, endowing it with an outstanding conductivity of 399.4 S cm−1. The film reaches a Ts of 204 °C with an input voltage of 3.0 V, and is successfully applied in water heating and de-icing, demonstrating its extraordinary electrothermal performance and vast potential for practical applications. The film is also used as an electromagnetic shielding film and heat dissipation substrate, showing exceptional electromagnetic shielding (42.5 dB) and heat dissipation properties.
制造高导电复合材料和构建高导电网络对高性能电热膜至关重要。在本研究中，通过液相剥离和原位光还原合成了银纳米线/石墨烯（Ag/G）复合材料，并将其与炭黑（CB）混合形成复合导电墨水，通过叶片涂覆工艺获得了具有点-线-面三维微观结构的CB/Ag/G复合电热膜。银纳米线的加入和随后的压轧处理都促使薄膜中有效导电网络的建立，使其具有 399.4 S cm-1 的出色电导率。在输入电压为 3.0 V 的情况下，薄膜的温度可达 204 °C，并成功应用于水加热和除冰，显示了其非凡的电热性能和巨大的实际应用潜力。该薄膜还可用作电磁屏蔽膜和散热基板，显示出卓越的电磁屏蔽（42.5 dB）和散热性能。
{"title":"Multifunctional and high-performance electrothermal films based on carbon black/Ag nanowires/graphene composites","authors":"Zijian Wang, Wen Yu, Chaochao Gao, Zhenye Zhu, Jiaheng Zhang","doi":"10.1038/s41528-024-00336-w","DOIUrl":"10.1038/s41528-024-00336-w","url":null,"abstract":"Fabricating high-conductive composites and constructing highly conductive networks are crucial for high-performance electrothermal film. In this study, an Ag nanowires/graphene (Ag/G) composite synthesized by liquid-phase exfoliation and in-situ photoreduction is mixed with carbon black (CB) to form a composite conductive ink, and a CB/Ag/G composite electrothermal film with a point-line-plane three-dimensional microstructure is obtained via blade coating process. Both the addition of Ag nanowires and a subsequent compression rolling treatment induce the establishment of the effective conductive network in the film, endowing it with an outstanding conductivity of 399.4 S cm−1. The film reaches a Ts of 204 °C with an input voltage of 3.0 V, and is successfully applied in water heating and de-icing, demonstrating its extraordinary electrothermal performance and vast potential for practical applications. The film is also used as an electromagnetic shielding film and heat dissipation substrate, showing exceptional electromagnetic shielding (42.5 dB) and heat dissipation properties.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":null,"pages":null},"PeriodicalIF":12.3,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00336-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142050639","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 : 2024-08-24DOI: 10.1038/s41528-024-00338-8
Mina Riahi, Kou Yoshida, Ifor D. W. Samuel
Flexible organic light-emitting diodes (OLEDs) are promising light sources for biomedical applications. However, the use of these flexible devices has been restricted by their short shelf lifetimes due to poor ambient stability. Here, the fabrication of a long-lived flexible OLED is reported by replacing air-sensitive metals such as aluminum, and alkali metals used as n dopants, with silver. In addition, to achieve stable and efficient flexible OLEDs we tuned the optical cavity length to the second-order interference maximum. The device design has simple encapsulation and leads to an improvement in the air stability of flexible OLEDs which show a shelf lifetime of greater than 130 days whereas the conventional structure exhibits degradation after only 12 days. The proposed design for making flexible OLEDs demonstrates a great potential for using the devices for wearable bioelectronic applications.
{"title":"Improving the air stability of flexible top-emitting organic light-emitting diodes","authors":"Mina Riahi, Kou Yoshida, Ifor D. W. Samuel","doi":"10.1038/s41528-024-00338-8","DOIUrl":"10.1038/s41528-024-00338-8","url":null,"abstract":"Flexible organic light-emitting diodes (OLEDs) are promising light sources for biomedical applications. However, the use of these flexible devices has been restricted by their short shelf lifetimes due to poor ambient stability. Here, the fabrication of a long-lived flexible OLED is reported by replacing air-sensitive metals such as aluminum, and alkali metals used as n dopants, with silver. In addition, to achieve stable and efficient flexible OLEDs we tuned the optical cavity length to the second-order interference maximum. The device design has simple encapsulation and leads to an improvement in the air stability of flexible OLEDs which show a shelf lifetime of greater than 130 days whereas the conventional structure exhibits degradation after only 12 days. The proposed design for making flexible OLEDs demonstrates a great potential for using the devices for wearable bioelectronic applications.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":null,"pages":null},"PeriodicalIF":12.3,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00338-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142045346","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 : 2024-08-08DOI: 10.1038/s41528-024-00337-9
Lixue Tang, Huayi Wang, Jifeng Ren, Xingyu Jiang
Stretchable electronic circuits can seamlessly conform to irregular and dynamic surfaces with high integration. However, current stretchable configurations typically have limited stretchability due to the lack of robust connections between soft interconnects and rigid electronics. Here, we printed highly stretchable metal–polymer conductors on thermoplastic elastomers as interconnects. We developed electronic vests with porous surfaces for rigid electronics and introduced polyester hot-melt adhesives to strengthen connections between soft interconnects and rigid electronics. After thermal bonding, the adhesive penetrates the porous surface of electronic vests, creating a mechanical interlock and providing an adhesion force of 8.34 N/cm for the connection (3× higher than conductive adhesives). Thus, rigid electronics of different sizes and different pin counts can form strong connections to soft interconnects, achieving a maximum strain tolerance of ~700% (10× higher than conductive adhesives). We achieved highly integrated ultra-stretchable displays that can withstand stretching up to 220% without dead pixels.
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Pub Date : 2024-08-02DOI: 10.1038/s41528-024-00335-x
Shuyun Zhuo, Alexandre Tessier, Mina Arefi, Anan Zhang, Chris Williams, Shideh Kabiri Ameri
Recently electronic tattoo sensors have attracted immense interest for health monitoring mainly due to their higher sensing performance than conventional dry sensors, owing to the ultra-low thickness which results in their conformability to the skin. However, their performance is worse than wet sensors. Further, these electronic tattoo sensors are not durable and reusable when free-standing because of their low thickness and being too delicate. Here, we report a remarkably high-performance freestanding, reusable, ultrathin and ultra-soft electronic tattoo sensor made of parylene-hydrogel double layer system with high water retention over extended periods that can be used for the extended period of 6 months. The hydrogel electronic tattoo (HET) sensors consist of electrically conductive self-adhesive hydrogel with a thickness of 20 µm and Young’s modulus of only 31 kPa at 37 °C, allowing for ultra-conformal contact to the skin microscopic features. Our HET sensors are fabricated using a scalable cost-effective method on ordinary tattoo papers and are laminated on the skin like temporary tattoos and were used for electrophysiological signals recording such as electrocardiography (ECG), electromyography (EMG), and skin hydration, temperature sensing. The HET sensors, for the first time, show 234% lower sensor-skin interface impedance (SSII) and significantly lower susceptibility to motion than gold standard medical grade silver/silver chloride wet gel electrodes which are known to have the lowest SSII and susceptibility to motion. Further, the low HET-skin interface impedance leads to a considerably larger signal amplitude and signal-to-noise ratio (SNR) of the electrophysiological signals recorded using HET sensors in comparison with those obtained using gold standard medical grade silver/silver chloride wet gel electrodes. The SNR of some types of electrophysiological signals such as EMG recorded using HET is up to 19 dB higher than gold standard medical grade electrodes due to higher signal amplitude, significantly lower susceptibility of HET to motion and lower motion artifacts. Also, the HET sensor is the first free-standing ultrathin tattoo sensor that can be transferred from the skin to tattoo paper and vice versa many times and the electrophysiological sensing quality remained high during repeated use for over 6 months.
最近，电子纹身传感器在健康监测领域引起了极大的兴趣，这主要是由于电子纹身传感器的超低厚度使其能够贴合皮肤，因此其传感性能高于传统的干式传感器。不过，它们的性能比湿传感器差。此外，这些电子纹身传感器由于厚度低、过于脆弱，在独立使用时不耐用，也不能重复使用。在此，我们报告了一种性能卓越的独立式、可重复使用、超薄和超柔软的电子纹身传感器，它由对二甲苯水凝胶双层系统制成，具有较高的保水性，可长期使用 6 个月。水凝胶电子纹身（HET）传感器由导电自粘性水凝胶组成，厚度为 20 微米，37 °C 时的杨氏模量仅为 31 千帕，可与皮肤微观特征超适形接触。我们的 HET 传感器是在普通纹身纸上采用可扩展的低成本方法制造的，像临时纹身一样贴在皮肤上，用于记录电生理信号，如心电图（ECG）、肌电图（EMG）以及皮肤水合作用和温度传感。与已知具有最低 SSII 和运动敏感性的金标准医用级银/氯化银湿凝胶电极相比，HET 传感器的传感器-皮肤界面阻抗（SSII）首次降低了 234%，运动敏感性也显著降低。此外，与使用金标准医用级银/氯化银湿凝胶电极记录的电生理信号相比，HET-皮肤界面阻抗低导致使用 HET 传感器记录的电生理信号的信号幅度和信噪比（SNR）大得多。使用 HET 记录的某些类型的电生理信号（如肌电图）的信噪比比金标准医疗级电极高出 19 分贝，这是因为 HET 的信号振幅更高，对运动的敏感性明显降低，运动伪影也更少。此外，HET 传感器还是首个独立式超薄纹身传感器，可多次从皮肤转移到纹身纸上，反之亦然。
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