Hansel Alex Hobbie, James L. Doherty, Brittany N. Smith, Paolo Maccarini, Aaron D. Franklin
{"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":" ","pages":"1-12"},"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}
Hongbin An, Xian Wang, Zhikang Liao, Liang Zhang, Hui Zhao, Yingyun Yang, Jizhou Song, Yinji Ma
{"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":" ","pages":"1-14"},"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}
{"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":" ","pages":"1-6"},"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}
{"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":" ","pages":"1-10"},"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}
{"title":"Highly robust soft-rigid connections via mechanical interlocking for assembling ultra-stretchable displays","authors":"Lixue Tang, Huayi Wang, Jifeng Ren, Xingyu Jiang","doi":"10.1038/s41528-024-00337-9","DOIUrl":"10.1038/s41528-024-00337-9","url":null,"abstract":"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.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-10"},"PeriodicalIF":12.3,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00337-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141904676","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}
Shuyun Zhuo, Alexandre Tessier, Mina Arefi, Anan Zhang, Chris Williams, Shideh Kabiri Ameri
{"title":"Reusable free-standing hydrogel electronic tattoo sensors with superior performance","authors":"Shuyun Zhuo, Alexandre Tessier, Mina Arefi, Anan Zhang, Chris Williams, Shideh Kabiri Ameri","doi":"10.1038/s41528-024-00335-x","DOIUrl":"10.1038/s41528-024-00335-x","url":null,"abstract":"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.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-11"},"PeriodicalIF":12.3,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00335-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141880286","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}
Shuchang He, Chengjun Wang, Jie Tao, Haishan Tang, Zuojia Wang, Jizhou Song
{"title":"A kirigami-based reconfigurable metasurface for selective electromagnetic transmission modulation","authors":"Shuchang He, Chengjun Wang, Jie Tao, Haishan Tang, Zuojia Wang, Jizhou Song","doi":"10.1038/s41528-024-00334-y","DOIUrl":"10.1038/s41528-024-00334-y","url":null,"abstract":"Tunable three-dimensional (3D) electromagnetic metasurfaces are essential for achieving selective modulation of polarized waves, but they usually require complex designs and the use of smart materials, posing great implementation challenges. Here, we propose a novel kirigami-based reconfigurable electromagnetic metasurface, which consists of a kirigami-based deformable thin polyimide substrate and periodically arranged copper split-ring resonators. By simple stretch, the two-dimensional (2D) planar metasurface can be uniformly transformed into a 3D state, enabling it to effectively and selectively modulate linearly and circularly polarized waves. Experimental and numerical results reveal the mechanical deformation and transmission characteristics of the metasurface under applied strains. It is shown that the metasurface exhibits good selective transmission tunability while the resonant frequency remains basically unchanged for both transverse electric and transverse magnetic polarized waves. Furthermore, the selective tuning mechanism and the influence of geometrical parameters are also illustrated by the equivalent circuit analysis.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-9"},"PeriodicalIF":12.3,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00334-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141877669","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}
Chenhao Wang, Zhengyu Wang, Wei Wei, Zhenjie Zhang, Anne Ailina Li, Guanghao Huang, Xian Li, Shuzhi Sam Ge, Lianqun Zhou, Hui Kong
{"title":"High-precision flexible sweat self-collection sensor for mental stress evaluation","authors":"Chenhao Wang, Zhengyu Wang, Wei Wei, Zhenjie Zhang, Anne Ailina Li, Guanghao Huang, Xian Li, Shuzhi Sam Ge, Lianqun Zhou, Hui Kong","doi":"10.1038/s41528-024-00333-z","DOIUrl":"10.1038/s41528-024-00333-z","url":null,"abstract":"As a stress hormone existing in the human body, cortisol can reflect the psychological stress and health status in daily life, and is a potential biomarker of the body’s stress response. To effectively collect sweat and accurately identify the target, this paper reports a flexible wearable cortisol detection device with outstanding reliability and sensitivity. Molecular imprinted polymer (MIP) ensures cortisol specificity. And carbon nanotubes (CNT) on electrodes increase sensitivity, expanding the detection range to 10−3 to 104 nM, with sensitivity at 189.2 nA/lg(nM). In addition, porous chitosan hydrogel (PCSH) collects sweat effectively, its adhesive properties and 80% swelling rate offer a low-cost alternative to microfluidics. Flexible printed circuit board (FPCB) and serpentine electrode (SE) ensure device durability. This non-invasive, highly sensitive device offers a novel method for mental stress monitoring and clinical diagnosis, advancing human physiological state monitoring.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-10"},"PeriodicalIF":12.3,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00333-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141790982","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}
{"title":"Tailored molecular for ultra-stability and biocompatible pseudohalide metal-free perovskite towards X-ray detectors with record sensitivity","authors":"Yutian Lei, Mengying Yin, Chang Shi, Lingxi Wu, Guoqiang Peng, Youkui Xu, Haoxu Wang, Rongbing Tang, ZhenHua Li, Zhiwen Jin","doi":"10.1038/s41528-024-00330-2","DOIUrl":"10.1038/s41528-024-00330-2","url":null,"abstract":"The emerging pseudohalide metal-free perovskite (pseudohalide–MFPs) X-ray detector caters to the demands of timely mobile diagnosis owing to its lightweight, flexibility, and cost-effectiveness. However, the performance of these devices is severely limited by poor X-ray absorption, ultra-wide band gap, relative instability, and their unknown biotoxicity. Herein, we construct heavy atom covalent bonds (C–Br/Cl) on the A-site organic cation to reinforce component coordination to modulate X-ray absorption and band gap in pseudohalide–MFPs and further enhance its stability. Molecular dynamics simulations demonstrate that the introduction of halogen atoms can strengthen hydrogen bonding interactions, thereby improving the coordination between different components. The resultant (MDABCOBr)–NH4(BF4)3 (MDABCO = N-methyl-N’-diazabicyclo[2.2.2]octonium) single crystal significantly increases X-ray absorption cross-section and crystalline density (from 1.728 to 1.950 g cm−3), and synergistically realizes the band nature modulation (from 7.4 to 5.5 eV) and enhanced ionic migration inhibition (628 meV) with optimized stability. As such, our X-ray detectors realized a sensitivity of 2377 μC Gyair−1 cm−2, an ultralow detection limit of 50.1 nGyair s−1, and impressive operation stability. Moreover, cytotoxicity assay confirmed the compatibility of pseudohalide metal-free perovskite. Finally, within this framework, we successfully fabricate the (MDABCOBr)–NH4(BF4)3-based flexible device to create an ideal in vitro wearable X-ray detection.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-10"},"PeriodicalIF":12.3,"publicationDate":"2024-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00330-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141791124","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}
H. Jessica Pereira, Oleg Makarovsky, David. B. Amabilino, Graham N. Newton
{"title":"Room temperature compressed air-stable conductive copper films for flexible electronics","authors":"H. Jessica Pereira, Oleg Makarovsky, David. B. Amabilino, Graham N. Newton","doi":"10.1038/s41528-024-00331-1","DOIUrl":"10.1038/s41528-024-00331-1","url":null,"abstract":"The state-of-the-art technology of fabricating printed copper electronics is focussed largely on thermal sintering restricting transition towards heat sensitive flexible substrates. Herein we report a pioneering technology which eliminates the need for conventional sintering. Biopolymer-stabilised copper particles are prepared such that they can be compressed at room temperature to generate air-stable films with very low resistivities (2.05 – 2.33 × 10−8 Ω m at 20 °C). A linear positive correlation of resistivity with temperature verifies excellent metallic character and electron microscopy confirms the formation of films with low porosity (< 4.6%). An aqueous ink formulation is used to fabricate conductive patterns on filter paper, first using a fountain/dip pen and then printing to deposit more defined patterns (R < 2 Ω). The remarkable conductivity and stability of the films, coupled with the sustainability of the approach could precipitate a paradigm-shift in the use of copper inks for printable electronics.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-12"},"PeriodicalIF":12.3,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00331-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141769079","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}