Article
Nanoscience & Nanotechnology
Chengjie Jiang, Tianyu Li, Xian Huang, Rui Guo
Summary: This study proposes a simple and rapid method for preparing patterned liquid-metal-enabled universal soft electronics (PLUS-E). The PLUS-E exhibits rapid fabrication, excellent stretchability, and high forming accuracy. The stability of PLUS-E on 3D surfaces is improved by using low-fluidity liquid metal composites. The finite element simulation accurately forecasts the deformation and resistance changes of the PLUS-E and provides guidance for device design. Various sensors developed using this method have demonstrated stable and reliable signal measurements in real-world applications.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Bin Chen, Guanglei Liu, Minying Wu, Yudong Cao, Haibin Zhong, Jianfeng Shen, Mingxin Ye
Summary: Currently, there is a growing interest in the development of organohydrogel-based wearable flexible electronics (WFEs) due to their superior environmental stability compared to hydrogel-based WFEs. In this study, an efficient strategy is proposed to achieve the quick preparation of organohydrogels by utilizing the high reactivity of eutectic gallium-indium alloy and constructing a glycerol/water binary solvent system. The resulting organohydrogels, named liquid metal-based ion-conducting organohydrogels (LMIOs), demonstrate excellent environmental adaptability, high transparency, and remarkable mechanical properties and self-healing abilities, making them suitable for sensing human motions and applications in skin-attachable devices, robotics, and prosthetics.
ADVANCED MATERIALS TECHNOLOGIES
(2023)
Review
Chemistry, Multidisciplinary
Guixuan Lu, Erli Ni, Yanyan Jiang, Weikang Wu, Hui Li
Summary: This review highlights the advancements and applications of room-temperature gallium-based liquid metals (RT-GaLMs) in flexible electronics. The physicochemical characteristics of RT-GaLMs and their regulation, as well as their diverse applications in self-healing circuits, flexible sensors, energy harvesting devices, and epidermal electronics, are discussed. The challenges and future research directions in this emerging field are also addressed.
Review
Chemistry, Multidisciplinary
Manuel Reis Carneiro, Carmel Majidi, Mahmoud Tavakoli
Summary: Soft and stretchable electronics have various applications in different fields, including compliant bioelectronics, textile-integrated wearables, mechanical sensors, electronics skins, and soft robotics. Gallium-based liquid metals have been proposed as deformable conductors with high electrical conductivity and self-healing property. However, their deposition and patterning is challenging. Recent development of biphasic conductor architectures, combining solid-phase materials and liquid-phase conductors, aims to address this challenge and achieve scalable fabrication of reliable stretchable circuits. This article reviews the recent progress in biphasic conductor architectures and their applications in soft electronic systems, discussing material combinations, printing and patterning methods, and potential applications.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Engineering, Biomedical
Yan Niu, Gongwei Tian, Cuiyuan Liang, Tianchi Wang, Xu Ma, Guifen Gong, Dianpeng Qi
Summary: Thermal-sinterable EGaIn nanoparticle inks are prepared by introducing thermal expansion microspheres (TEMs) into EGaIn NP solution. Through the expansion of the heated TEMs, the printed EGaIn NPs can be sintered into electrically conductive paths, achieving highly stretchable bioelectrode arrays with excellent performance. The sintering strategy overcomes the disadvantages of traditional strategies and promotes the application of EGaIn in soft electronics.
ADVANCED HEALTHCARE MATERIALS
(2023)
Review
Chemistry, Multidisciplinary
Robert W. Style, Ravi Tutika, Jin Young Kim, Michael D. Bartlett
Summary: Solid-liquid composites, incorporating liquid phases like water, liquid metals, or complex fluids into solid materials, have emerged as a new paradigm in material design, showcasing unique properties and characteristics due to the vastly different properties of liquids and solids. In recent years, the development of solid-liquid composites has led to the study and application of novel materials with new functional responses in various fields, such as soft electronics, robotics, 3D printing, wet granular systems, and cell biology.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
A. B. M. Tahidul Haque, Dong Hae Ho, Dohgyu Hwang, Ravi Tutika, Chanhong Lee, Michael D. D. Bartlett
Summary: A heterogeneous liquid metal-based conductive adhesive, STICK-LM, is developed for the integration of dissimilar material components in soft electronic and robotic systems. It exhibits high stretchability, low modulus, and strain-invariant electrical conductivity. The adhesive enables reversible adhesion with enhanced adhesion energies and provides design guidelines for controllable adhesion in conductive systems.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
M. Ntagios, Ravinder Dahiya
Summary: This work presents a soft, flexible, and low-cost capacitive pressure-sensitive insole developed using resource-efficient single-step 3D printing method. The insole exhibits excellent pressure response and sensitivity, making it a promising solution for applications such as gait analysis and robotics.
IEEE SENSORS JOURNAL
(2023)
Article
Chemistry, Physical
Hongyue Wang, Yongmin Zhang, Xinyu He, Fang Zuo, Yaoyue Yang, Ping Yan, Bin Luo, Shuai He
Summary: This study examines the wettability of liquid metals on PEDOT:PSS and develops an efficient method for preparing liquid-metal soft electronics. The synergistic effect between liquid metals and PEDOT:PSS enables non-corrosive electrical connections and offers potential for flexible electronics and wearable sensors.
APPLIED SURFACE SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Yue Li, Alan F. Rodriguez-Serrano, Sin Yu Yeung, I-Ming Hsing
Summary: This study presents an adhesive, highly stretchable and conformal (ASC) patch for long-term ambulatory ECG monitoring, offering a revolutionary approach to cardiovascular disease diagnosis. The ASC patch demonstrates enhanced mechanical and electrical properties, providing stable high-quality ECG signals in various conditions. This work paves the way for scalable wearable ECG devices and new opportunities in medical applications in soft electronics.
ADVANCED MATERIALS TECHNOLOGIES
(2022)
Review
Nanoscience & Nanotechnology
Elizabeth Bury, Seth Chun, Amanda S. Koh
Summary: Deformable electronics with liquid metal enable previously inaccessible mechanical behaviors and exciting new technologies. By utilizing liquid metals and soft, stretchable materials, devices can achieve comparable or better electrical performance while providing stretchability and improving safety and comfort between humans and machines.
ADVANCED ELECTRONIC MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Jiexian Ma, Zihan Liu, Quang-Kha Nguyen, Pu Zhang
Summary: Liquid metal composites embedded with a network of liquid metal fibers show promise as lightweight and highly conductive materials for stretchable interconnects, electrodes, and sensors in soft electronics and robotics.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Robotics
Aby P. M. Raj, Thileepan Stalin, Pablo Valdivia Y. Alvarado
Summary: The study demonstrated the successful fabrication of tailored soft inductive coils using Automated Fiber Embedding (AFE) techniques, showcasing their versatility in various applications.
IEEE ROBOTICS AND AUTOMATION LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Xing Peng Hao, Chuan Wei Zhang, Xin Ning Zhang, Li Xin Hou, Jian Hu, Michael D. Dickey, Qiang Zheng, Zi Liang Wu
Summary: In recent years, sustainable materials have experienced rapid development, with particular emphasis on the development of biodegradable or recyclable soft electronics. These soft electronics have versatile applications in areas such as biomedical devices, soft robots, and wearables. Researchers have reported on the development of sustainable hydrogel-based soft electronics (HSE) that integrate sensing elements and patterned liquid metal (LM) in a gelatin-alginate hybrid hydrogel. This HSE is transparent, robust, resilient, and recyclable, and possesses multifunctional capabilities, including strain and temperature sensing, heart rate monitoring, pH detection, and iontophoretic drug delivery. It also enables noncontact detection of nearby objects using electrostatic-field-induced voltage. The LM and biopolymer hydrogel used in the HSE are healable, recyclable, and degradable, making them ideal for sustainable applications and reconstruction of the device with new functions. Such HSE with multiple functions and favorable attributes holds significant potential in the development of next-generation electronic skins and hydrogel machines.
Review
Chemistry, Multidisciplinary
Tomoyuki Yokota, Kenjiro Fukuda, Takao Someya
Summary: Flexible image sensors are gaining attention as new imaging devices due to their lightness, softness, and bendability. They offer high-accuracy continuous biometric information measurement directly attached to curved surfaces like skin, with potential applications in wearable devices and home medical care. The individual components, performance evaluation parameters, and real-world measurement cases of these sensors in the biomedical field are discussed.
ADVANCED MATERIALS
(2021)
Article
Engineering, Electrical & Electronic
Zhimin Yang, Jaeman Song, Bong Jae Lee
Summary: In this study, the performance of graphene-based Schottky junction thermophotovoltaic (TPV) devices in near-field conditions is investigated. It is found that the semiconductor layer dominates the generation of photocurrent, with a less than 40% internal quantum efficiency (IQE) for graphene. Under an emitter temperature of 1000 K and a vacuum gap of 100 nm, using an indium tin oxide (ITO)-covered tungsten (W) emitter can increase photocurrents by a factor of around 10 and 11 for the semiconductor and graphene, respectively. Furthermore, using a hyperbolic metamaterial (HMM) emitter can enhance photocurrents by around 4.7 and 5.2 times for the semiconductor and graphene, respectively, at the cost of higher heat flux from the HMM emitter. These findings provide valuable insights for the design and optimization of TPV devices to improve their photocurrent and efficiency.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Multidisciplinary Sciences
Gyeongsuk Park, Hyunmin Park, Junyong Seo, Jun Chang Yang, Min Kim, Bong Jae Lee, Steve Park
Summary: The authors developed a hydrogel that mimics thermal homeostasis, providing improved heat trapping and enhanced evaporative cooling. The hydrogel includes materials that reflect and absorb infrared waves for heat trapping at low temperatures, and has a porous structure for enhanced evaporative cooling at high temperatures. An optimized auxetic pattern acts as a heat valve to amplify heat release. This hydrogel provides effective bidirectional thermoregulation, making it useful for autonomic nervous system disorders and susceptible soft robotics.
NATURE COMMUNICATIONS
(2023)
Article
Optics
Yongjin Na, Hyunsoo Kwak, Changmin Ahn, Seung Eon Lee, Woojin Lee, Chu-Shik Kang, Jungchul Lee, Junho Suh, Hongki Yoo, Jungwon Kim
Summary: High-speed and high-resolution imaging of surface profiles is essential for studying various structures and mechanical dynamics in micro- and nano-scale devices. However, capturing real-time and complex mechanical dynamics has been challenging. In this study, we present a line-scan time-of-flight (TOF) camera that can measure the TOF changes of over 1000 spatial coordinates simultaneously, with high pixel-rate and sub-nanometer axial resolution. This camera enables fast and precise imaging of complex structures and dynamics in three-dimensional devices and mechanical resonators.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Article
Physics, Applied
Jose Ordonez-Miranda, Yuriy A. Kosevich, Bong Jae Lee, Masahiro Nomura, Sebastian Volz
Summary: The thermal conductance and thermal conductivity of plasmons in metallic nanofilms deposited on a substrate were studied. The symmetric and antisymmetric spatial distribution modes of the magnetic field drive the plasmon energy transport along the film interfaces. The plasmon thermal conductance is higher for hotter and/or longer films, saturating for films thicker than 50 nm. The transition of plasmon modes maximizes the thermal conductivity for thinner films, and a 10 nm thick gold nanofilm at 300 K has a maximum thermal conductivity of 15 W m-1 K-1, about 25% of its electron counterpart. The plasmon thermal conductivity increases significantly with film length and temperature, potentially improving heat dissipation along metallic nanofilms.
PHYSICAL REVIEW APPLIED
(2023)
Article
Green & Sustainable Science & Technology
Junyong Seo, Minwoo Choi, Siwon Yoon, Bong Jae Lee
Summary: This paper presents a practical approach to estimate the performance of radiative cooling, using the model of accumulated cold energy production (ACEP), and applies it to optimize and select photonic structures under different climatic conditions.
Article
Nanoscience & Nanotechnology
Juhee Ko, Bong Jae Lee, Jungchul Lee
Summary: In this paper, we report the development of heated fluidic resonators for simultaneous and quantitative thermophysical measurements of ultrasmall liquid volumes. By reducing thermal loss, we were able to significantly improve the precision of these resonators in a vacuum. The increased measurement sensitivities for thermal conductivity and specific heat capacity make the differentiation between liquids with similar properties more accurate.
MICROSYSTEMS & NANOENGINEERING
(2023)
Article
Automation & Control Systems
Jaewoo Jeong, Taeyeong Kim, Bong Jae Lee, Jungchul Lee
Summary: This study presents an alternative to conventional optical microscopy by training a deep learning model to predict surface topography from optical microscope images. The feasibility of this method is demonstrated using GON samples with high accuracy and resolution. The OM-based approach significantly improves measurement throughput and area, and can be operated under extreme conditions.
ADVANCED INTELLIGENT SYSTEMS
(2023)
Article
Instruments & Instrumentation
Jeongmin Nam, Dong-min Kim, Minwoo Choi, Jinsung Rho, Jungchul Lee, Bong Jae Lee
Summary: This article introduces a micro-infrared thermometer that utilizes a bolometer-type infrared detector and a reflective objective lens, allowing for high-resolution temperature measurements of microscale heating devices. The experimental results are reasonably consistent with COMSOL simulations.
INFRARED PHYSICS & TECHNOLOGY
(2023)
Review
Nanoscience & Nanotechnology
Taeyeong Kim, Jungchul Lee
Summary: Silicon nanoparticles play a crucial role in nanoscience and nanoengineering due to their high energy capacity and exceptional optical properties. This review provides an overview of different fabrication and characterization techniques for silicon nanoparticles, as well as their diverse applications. The review also offers insights into future advancements in silicon nanoparticle technology.
MICRO AND NANO SYSTEMS LETTERS
(2023)
Review
Nanoscience & Nanotechnology
Taeyeong Kim, Jungchul Lee
Summary: This article reviews the advantages of silicon-on-insulator (SOI) wafers in integrated circuits and microelectromechanical systems (MEMS), as well as the challenges in manufacturing and quality control. It also provides insights into the potential future directions of SOI technology.
MICRO AND NANO SYSTEMS LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Jaeman Song, Minwoo Choi, Bong Jae Lee
Summary: This study comprehensively investigates the effectiveness of multi-junction-based near-field thermophotovoltaic (NF-TPV) devices, considering additional losses. By proposing two approximative expressions and verifying against rigorously optimized results, a criterion for effective performance is established. Our method provides precise power output density estimations for different parameters and offers a roadmap for scalable design. The importance of multi-junction PV cells is emphasized, and vital insights for future high-performance TPV devices are provided.
