Soon Joo Yoon, Jeongdae Ha, Hyeokjun Lee, Jin Tae Park, Bin Hyung Lee, Kyung-In Jang, Anna Yang, Yoon Kyeung Lee
{"title":"Water-based direct photopatterning of stretchable PEDOT:PSS using amphiphilic block copolymers","authors":"Soon Joo Yoon, Jeongdae Ha, Hyeokjun Lee, Jin Tae Park, Bin Hyung Lee, Kyung-In Jang, Anna Yang, Yoon Kyeung Lee","doi":"10.1038/s41528-024-00308-0","DOIUrl":"10.1038/s41528-024-00308-0","url":null,"abstract":"The use of water-based chemistry in photolithography during semiconductor fabrication is desirable due to its cost-effectiveness and minimal environmental impact, especially considering the large scale of semiconductor production. Despite these benefits, limited research has reported successful demonstrations of water-based photopatterning, particularly for intrinsically water-soluble materials such as Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) due to significant challenges in achieving selective dissolution during the developing process. In this paper, we propose a method for the direct patterning of PEDOT:PSS in water by introducing an amphiphilic Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO, P123) block copolymer to the PEDOT:PSS film. The addition of the block copolymer enhances the stretchability of the composite film and reduces the hydrophilicity of the film surface, allowing for water absorption only after UV exposure through a photoinitiated reaction with benzophenone. We apply this technique to fabricate tactile and wearable biosensors, both of which benefit from the mechanical stretchability and transparency of PEDOT:PSS. Our method represents a promising solution for water-based photopatterning of hydrophilic materials, with potential for wider applications in semiconductor fabrication.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-10"},"PeriodicalIF":14.6,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00308-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140345846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wooyeon Kim, Jigeon Kim, Dayoung Kim, Bonkee Koo, Subin Yu, Yuelong Li, Younghoon Kim, Min Jae Ko
{"title":"Completely annealing-free flexible Perovskite quantum dot solar cells employing UV-sintered Ga-doped SnO2 electron transport layers","authors":"Wooyeon Kim, Jigeon Kim, Dayoung Kim, Bonkee Koo, Subin Yu, Yuelong Li, Younghoon Kim, Min Jae Ko","doi":"10.1038/s41528-024-00305-3","DOIUrl":"10.1038/s41528-024-00305-3","url":null,"abstract":"The electron transport layer (ETL) is a critical component in perovskite quantum dot (PQD) solar cells, significantly impacting their photovoltaic performance and stability. Low-temperature ETL deposition methods are especially desirable for fabricating flexible solar cells on polymer substrates. Herein, we propose a room-temperature-processed tin oxide (SnO2) ETL preparation method for flexible PQD solar cells. The process involves synthesizing highly crystalline SnO2 nanocrystals stabilized with organic ligands, spin-coating their dispersion, followed by UV irradiation. The energy level of SnO2 is controlled by doping gallium ions to reduce the energy level mismatch with the PQD. The proposed ETL-based CsPbI3-PQD solar cell achieves a power conversion efficiency (PCE) of 12.70%, the highest PCE among reported flexible quantum dot solar cells, maintaining 94% of the initial PCE after 500 bending tests. Consequently, we demonstrate that a systemically designed ETL enhances the photovoltaic performance and mechanical stability of flexible optoelectronic devices.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-11"},"PeriodicalIF":14.6,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00305-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140164505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Flexible and wearable battery-free backscatter wireless communication system for colour imaging","authors":"Jun-Lin Zhan, Wei-Bing Lu, Cong Ding, Zhen Sun, Bu-Yun Yu, Lu Ju, Xin-Hua Liang, Zhao-Min Chen, Hao Chen, Yong-Hao Jia, Zhen-Guo Liu, Tie-Jun Cui","doi":"10.1038/s41528-024-00304-4","DOIUrl":"10.1038/s41528-024-00304-4","url":null,"abstract":"Wireless imaging, equipped with ultralow power wireless communications and energy harvesting (EH) capabilities, have emerged as battery-free and sustainable solutions. However, the challenge of implementing wireless colour imaging in wearable applications remains, primarily due to high power demands and the need to balance energy harvesting efficiency with device compactness. To address these issues, we propose a flexible and wearable battery-free backscatter wireless communication system specially designed for colour imaging. The system features a hybrid RF-solar EH array that efficiently harvests energy from both ambient RF and visible light energy, ensuring continuous operation in diverse environments. Moreover, flexible materials allow the working system to conform to the human body, ensuring comfort, user-friendliness, and safety. Furthermore, a compact design utilizing a shared-aperture antenna array for simultaneous wireless information and power transfer (SWIPT), coupled with an optically transparent stacked structure. This design not only optimizes space but also maintains the performance of both communication and EH processes. The proposed flexible and wearable systems for colour imaging would have potentially applications in environmental monitoring, object detection, and law enforcement recording. This approach demonstrates a sustainable and practical solution for the next generation of wearable, power-demanding devices.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-9"},"PeriodicalIF":14.6,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00304-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140135500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Keon-Woo Kim, Seong Ju Park, Su-Jeong Park, Inae Kim, Bomi Park, Se Hyun Kim, Unyong Jeong, Jin Kon Kim, Chanwoo Yang
{"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":" ","pages":"1-9"},"PeriodicalIF":14.6,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00306-2.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}
Minwoo Nam, Jaehyeock Chang, Hagseon Kim, Young Hyun Son, Yongmin Jeon, Jeong Hyun Kwon, Kyung Cheol Choi
{"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":" ","pages":"1-14"},"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}
{"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":" ","pages":"1-10"},"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}
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
{"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":" ","pages":"1-14"},"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}
{"title":"Ultra-sensitive, highly linear, and hysteresis-free strain sensors enabled by gradient stiffness sliding strategy","authors":"Fuhua Xue, Qingyu Peng, Renjie Ding, Pengyang Li, Xu Zhao, Haowen Zheng, Liangliang Xu, Zhigong Tang, Xinxing Zhang, Xiaodong He","doi":"10.1038/s41528-024-00301-7","DOIUrl":"10.1038/s41528-024-00301-7","url":null,"abstract":"Developing strain sensors with both high sensitivity and high linearity has always been the goal of researchers. Compared to resistive strain sensors, capacitive strain sensors have incomparable linearity advantages, but have always been limited by low sensitivity. Here, we report a gradient stiffness sliding design strategy that addresses this problem, significantly improving sensitivity while maintaining high linearity. By controlling the distribution of the locally enhanced electric field and the heterogeneous deformation of the substrate, a strain sensor with excellent performance is successfully prepared, exhibiting a giant gauge factor (9.1 × 106) and linearity (R2 = 0.9997) over the entire sensing range, together with almost no hysteresis and fast response time (17 ms). The gradient stiffness sliding design is a general strategy expected to be applied to other types of sensors to achieve ultra-high sensitivity and ultra-high linearity at the same time.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-8"},"PeriodicalIF":14.6,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00301-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140053264","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}
Doyoung Kim, Seung Won Seon, Minkyung Shin, Jihwan Kim, Bogeun Kim, Janghoon Joo, Sang Uk Park, Wooseok Kim, Hee Kyu Lee, Byeong Woon Lee, Se Gi Lee, Su Eon Lee, Ji-Hun Seo, Seung Ho Han, Bong Hoon Kim, Sang Min Won
{"title":"Squid-inspired and wirelessly controllable display for active camouflage in aquatic-environment","authors":"Doyoung Kim, Seung Won Seon, Minkyung Shin, Jihwan Kim, Bogeun Kim, Janghoon Joo, Sang Uk Park, Wooseok Kim, Hee Kyu Lee, Byeong Woon Lee, Se Gi Lee, Su Eon Lee, Ji-Hun Seo, Seung Ho Han, Bong Hoon Kim, Sang Min Won","doi":"10.1038/s41528-024-00292-5","DOIUrl":"10.1038/s41528-024-00292-5","url":null,"abstract":"Achieving optimal camouflage in an aquatic environment necessitates the ability to modulate transmittance in response to the surrounding obscurity and potential threats. This adaptation involves a dynamic transition from transparency to a deep-blue color, especially in low-light or dark situations. Such a strategy promotes a seamless assimilation with the surroundings, enabling the absorption of searchlights and, subsequently, diminishing the risk of detection by predators. Therefore, the presence of sophisticated mechanisms that facilitates stable and efficient control of transmittance is imperative, enabling smooth transition between transparent and deep-blue hues within the aquatic environment. This study presents nature-inspired programmable camouflage system that integrates an electrochromic display as the primary transmittance change element and a wireless base module for power and data transmission. Such technology offers a robust and flexible construction, ensuring stable operation as demonstrated through mechanical-fatigue experiments and quantitative simulation. A custom circuit and a power-control software package enable active control of multiple electrochromic displays while submerged in water.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-10"},"PeriodicalIF":14.6,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00292-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140030060","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":"Multilayer stretchable electronics with designs enabling a compact lateral form","authors":"Dongwuk Jung, Hunpyo Ju, Sungbum Cho, Taeyeon Lee, Changeui Hong, Jongho Lee","doi":"10.1038/s41528-024-00299-y","DOIUrl":"10.1038/s41528-024-00299-y","url":null,"abstract":"Stretchable electronics are of huge interest as they can be useful in various irregular non-planar or deformable surfaces including human bodies. High density multi-functional stretchable electronics are beneficial as they can be reliably used in more compact regions. However, simply stacking multiple layers may increase induced strain, reducing degree of stretchability. Here, we present the design approach for the stretchable multilayer electronics that provide a similar degree of stretchability compare to a single layer electronics although the multilayer electronics are in much more compact form. We provide experimental and computational analyses for the benefits of the approach along with demonstrations with compact form of the multi-functional stretchable implantable bio-electronics and of the stretchable multilayer passive matrix LEDs array. The results presented here should be useful for a wide range of applications that require stretchable high-density electronics.","PeriodicalId":48528,"journal":{"name":"npj Flexible Electronics","volume":" ","pages":"1-9"},"PeriodicalIF":14.6,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41528-024-00299-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139916801","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}