ABSTRACT Personal thermal management (PTM) has emerged as a vital frontier for protecting individual health, mitigating societal energy burdens, and combating global climate change. Although traditionally focused on passive textiles for localized thermal comfort, the rapid evolution of stretchable, rigid‐flex bioelectronics has redefined the contemporary PTM landscape. Grounded in a statistical analysis of recent literature, this review establishes an expanded scope for PTM comprising four interconnected aspects: thermal sensing, thermal regulation, thermal therapy, and thermal energy harvesting. Although fundamental thermodynamic regulation remains the operational core, modern wearables increasingly leverage multifunctional material platforms for versatile and practical applications—ranging from physiological diagnosis and regulation to experiential demands of virtual and augmented reality. We systematically examine practical thermal regulation strategies, summarize emerging functional material platforms, and analyze application‐centered outcomes across diverse scenarios in both comfort and non‐comfort. Finally, we address critical bottlenecks hindering the transition from laboratory prototypes to industrial products, offering a forward‐looking perspective on the evolution from passive textiles toward multimodal, biomimetic, and data‐driven intelligent closed‐loop wearable systems.
ABSTRACT Human–machine interfaces increasingly require sensors capable of perceiving both direct physical interactions and remote environmental cues. However, existing multimodal flexible sensors typically rely on physically separated sensing units and complex signal integration, leading to increased structural complexity and compromised mechanical adaptability. Here, we present a flexible bimodal sensing architecture that enables contact and noncontact perception within a single configuration. The sensor is constructed from a silica‐modified gallium–indium liquid metal composite embedded in an elastomeric matrix, where a single patterned conductive framework enables dual sensing functions through distinct interaction modes. Resistance modulation of the deformable liquid metal network provides real‐time strain perception during physical contact, whereas triboelectric‐field coupling enables proximity detection without direct contact. This intrinsically integrated sensing strategy allows simultaneous decoding of deformation states, approaching distance, and dynamic motion trajectories without relying on conventional multisensor fusion. This single configuration‐based multimodal sensing strategy provides a compact approach for developing next‐generation electronic skins and intelligent human–machine interfaces.
ABSTRACT Flexible integrated electronic technology enables the next generation of more flexible, freer, lighter, and smaller intelligent hardware, providing information sensing and edge computing capabilities for applications such as embodied intelligence, healthcare, and industrial Internet of Things. By thinning and integrating diverse chips onto a thin‐film polymer substrate, these flexible integrated devices retain advantages of semiconductor devices, including high integration density, low power consumption, and mature front‐end processes, without altering the fundamental device structures and materials. Although the electrical performance of ultra‐thin chips remains essentially unchanged after flexible packaging, the mechanical reliability during repeated bending deformation has been a critical concern due to the significant property mismatch between silicon and polymer materials, which may cause silicon fracture, interfacial failure, and eventual device failure. This study investigates and evaluates the fatigue lifetime of 20‐μm‐thick chips under repeated bending deformation with various radii of curvature. Through systematic experiments, the typical failure phenomena evolution is observed, finding three types of failure modes including metal pad wearing, metal stress migration, and gold wire break. The underlying failure mechanisms have been analyzed and explained by micro‐scale characterization. Finally, temperature effect on the fatigue lifetime has been explored trying to throw light on heating‐based accelerated fatigue life assessment method for the flexible chips. Hopefully, this work can provide essential support for the design to large‐scale application of flexible integrated devices in the widespread intelligent hardware products.
Tendon repair remains challenging due to the poor intrinsic healing capacity of tendon tissue and the mechanical mismatch between conventional grafts or scaffolds and native tendon. In this study, a mechanically biomimetic flexible substrate composed of a flexible architecture covered with an electrospun film (both fabricated from polycaprolactone/Type u2160 collagen (PCL/COL)) was developed for the dynamic culture of tendonu2010derived stem cells (TDSCs). The cast PCL/COL composite film exhibited an elastic modulus of 130.00 MPa and a yield stress of 5.00 MPa. Fourier transform infrared spectroscopy confirmed the successful incorporation of collagen, whereas water contact angle measurements showed improved hydrophilicity. A phenomenological model and inverse design strategy were then used to generate a horseshoeu2010microstructured flexible substrate that reproduced the nonlinear tensile response of the rat Achilles tendon, with good agreement among the model, finite element analysis, and experimental results. In vitro cell experiments were performed on the COL/PCL flexible substrate, PCL flexible substrate, and straightu2010beam substrate. The PCL/COL composite showed no obvious cytotoxicity and better cytocompatibility than pure PCL. Under cyclic tensile stimulation, TDSCs exhibited enhanced elongation, alignment, and expression of SCX, TNMD, collagen u2160, and collagen u2162, particularly on the COL/PCL flexible substrate. These results demonstrate its potential for tendon tissue engineering by providing a favorable microenvironment for tenogenic differentiation and tendonu2010like matrix formation.
This paper presents a comprehensive study on the active stiffness modulation of flexible structures using Shape Memory Alloy (SMA)u2010elastomer composites. We developed a robust fabrication process for creating NiTi wireu2010reinforced Polydimethylsiloxane (PDMS) composites. The effective Young's modulus of the composite was characterized experimentally over a temperature range from u22125 to 90u2103, revealing a threefold stiffness increase (from ~15 to ~45 MPa) when the NiTi wires are heated above their austenite finish temperature. Both theoretical analysis based on the rule of mixtures and finite element simulations showed excellent agreement with the experimental data, which paves the way for design and implementation of active stiffness modulation of the composite's macroscopic stiffness by direct Joule heating. This work establishes a foundational framework for developing variableu2010stiffness flexible structures with potential applications in soft robotics, morphing skins, and aerospace deployables.
ABSTRACT Macrocyclic molecules, with their three‐dimensional rigid frameworks and precisely modifiable cavity structures, provide a unique platform for the development of high‐performance organic light‐emitting diodes (OLED) emitters. To meet the stringent demands of ultrahigh‐definition and three‐dimensional displays for narrowband emission and circularly polarized luminescence, three major challenges must be addressed for current multiresonance (MR) narrowband emitters: further spectral narrowing, maintaining high emission efficiency in aggregated states despite their large planar structures, and achieving both narrow full‐width at half‐maximum and high asymmetry factors simultaneously. The introduction of postfunctionalized macrocycles offer a novel solution to this dilemma: their three‐dimensional rigid skeletons act as steric spacers that effectively isolate emissive centers, suppress intermolecular aggregation, and exciton annihilation, thereby preserving narrowband emission while significantly reducing the dependence of device performance on doping concentration. Furthermore, incorporating chiral groups or constructing chiral environments within macrocyclic frameworks can endow narrowband systems with circularly polarized luminescence (CPL) properties, opening new avenues for high‐color‐purity, high‐efficiency circularly polarized OLEDs (CP‐OLEDs), and advanced three‐dimensional displays. Thus, macrocyclic narrowband materials are not only expected to overcome the limitations of conventional small‐molecule narrowband emitters in terms of spectral broadening and aggregation‐induced quenching but also serve as an ideal molecular platform for the integration of chiral optoelectronic functions.
High-quality chest compressions are vital for successful cardiopulmonary resuscitation (CPR). Existing manual and mechanical compression methods suffer from unstable quality, lack of real-time feedback, and insufficient personalized adjustment. Here, we report a large-area, stretchable accelerometer array with the capability to monitor multi-point compression depth across the chest and achieve the cross-sectional chest contour at the peak compression. The proposed accelerometer array features stretchable discrete stiff island design and exhibits good mechanical adaptability to enable conformal contact with the chest region. A chest compression depth estimation algorithm based on triaxial acceleration data is developed to predict the compression depth. Moreover, a peak-averaging-based contour construction method is proposed to construct the deformed chest contour. The predicted compression depth and chest contour agree well with experimental measurements in both simple hollow semi-cylinder and complex adult manikin systems, demonstrating that the accelerometer array exhibits high spatiotemporal resolution in multi-point chest compression monitoring and dynamic tracking of thoracic deformation patterns. These results offer high spatiotemporal resolution for multi-point deformation tracking, providing key technical support for advancing the CPR feedback technologies.
Lattice thermal conductivity is a critical parameter for assessing the thermal transport properties of materials. When confined to the monolayer limit, two-dimensional materials display unique thermal characteristics distinct from their three-dimensional counterparts. This article first provides a concise summary of three widely applied experimental methodologies—Raman thermometry, suspended microbridge techniques, and time-domain thermoreflectance—and their utility in validating theoretical predictions. It subsequently delves into recent advancements in theoretical modeling, encompassing both equilibrium and nonequilibrium molecular dynamics studies; first-principles calculations grounded in the phonon Boltzmann transport equation that account for higher-order scattering phenomena such as four-phonon processes and phonon–electron interactions; emerging methods based on normal mode analysis for detailed phonon contribution decomposition; and novel approaches employing the Wigner transport equation to unify the description of phonon coherence and wave-like heat transport phenomena beyond conventional theoretical frameworks. In addition, the advent of machine learning has expanded the scope of direct thermal conductivity prediction and the development of high-precision interatomic potentials, paving the way for high-throughput screening and extensive simulations. This review contrasts the advantages and drawbacks of these methodologies, identifies key challenges facing the field, and sketches future directions for 2D thermal transport research, emphasizing the integration of multiscale modeling, data-driven innovation, and the synergy between experiments and theoretical insights.
In this study, a thermomechanical coupling finite element model of flexible electronic components with a periodic porous polydimethylsiloxane (PDMS) substrate was established to investigate the effects of thermal pulse loading rate and substrate porosity on their coupled thermomechanical response. The temperature, thermal stress, and displacement responses at the central point of the functional layer were analyzed under thermal pulses with different amplitudes and loading rates. The influence of substrate porosity on the distribution of these parameters within the functional layer was also evaluated. Results showed that the transient thermal stress and displacement responses in the substrate layer were significantly greater than those in the functional layer. This suggests that during the thermomechanical coupling process, the porous substrate absorbs more pulse energy, thereby ensuring the stable operation of the functional layer. Furthermore, these findings demonstrate that porous substrates can effectively dissipate external loads under thermomechanical coupling conditions. A lower porosity was found to mitigate the adverse effects of such coupling, which may extend the service life of the components. This study provides a quantitative basis for optimizing the structural design and durability of flexible electronic components.
Blue multi-resonance thermally activated delayed fluorescence (MR-TADF) emitters are pivotal for expanding the color gamut of organic light-emitting diodes (OLEDs), owing to their narrowband emission, high photoluminescence quantum yields, and rapid reverse intersystem crossing (RISC) characteristics. Among this, the rigid fused organoboron-nitrogen (BN) framework serves as a foundational scaffold for MR emitters, extensively studied to advance OLED performance. However, strategies to optimize the BN core for enhanced device efficiency while maintaining emission wavelength stability remain underexplored. In this work, we designed two 2,12-di- tert -butyl-5,9-bis(4-( tert -butyl)phenyl)-5,9-dihydro-5,9-diaza-13 b -boranaphtho[3,2,1- de ]anthracene ( t -DABNA) derivatives by introducing the methyl (Me)- and phenyl (Ph)-substituent, named Me- t -DABNA and Ph- t -DABNA, respectively. Subtle substituent tuning enabled precise modulation of device performance. Notably, Me- t -DABNA retained the deep-blue emission ( λ = 457 nm in toluene) and narrow full-width at half-maximum (FWHM = 22 nm) of the parent t -DABNA while significantly improving electroluminescence characteristics. The sensitized OLED based on Me- t -DABNA achieved a maximum external quantum efficiency (EQE) of 32.48%, with ultrapure blue emission ( λ = 461 nm, FWHM = 30 nm) and Commission Internationale de L'Eclairage (CIE) coordinates of (0.137, 0.123), outperforming the t -DABNA reference device. This work establishes methyl substitution as an effective approach for precise RISC enhancement in BN-core MR-TADF emitters, without compromising narrowband emission characteristics.
Robotic vision is essential for enabling intelligent and autonomous systems across diverse applications, including manufacturing, healthcare, autonomous navigation, and surveillance. However, conventional vision systems, which rely on rigid imaging hardware, face challenges such as limited adaptability, high energy consumption, and processing latency. Recently, flexible and stretchable photodetectors (PDs) have emerged as promising alternatives due to their advantages over rigid counterparts, making them ideal for robotic vision that requires multifunctionality and high energy efficiency to perform environment-specific tasks. Despite their potential, current research studies on deformable PDs have largely focused on improving basic properties such as softness and responsivity, limiting their practical implementation in robotic vision. To unlock their full potential, next-generation flexible and stretchable vision systems must integrate advanced image acquisition and processing capabilities. This review explores recent progress in vision systems with a focus on these two aspects. First, we examine bio-inspired vision systems that mimic structural and functional features of biological eyes to enhance image acquisition. Next, we describe vision systems integrated with in-sensor computing architecture that enables simultaneous image acquisition and processing. Finally, we discuss remaining challenges and propose future directions for developing next-generation flexible and stretchable vision systems to meet the growing demands of advanced robotic vision.
Wearable devices possess excellent flexibility and can conform to irregular surfaces, extensively changing human healthcare fields. Ultrasonic technology, with its extensive penetration depth, nondestructive nature, and versatile functionalities, has been widely applied in the diagnosis and treatment of various diseases. However, traditional ultrasound devices are often bulky and rigid, significantly limiting their further development in the biomedical field. Wearable and flexible ultrasound devices combine the advantages of wearable electronics and ultrasound technology, providing real-time, continuous, and nondestructive strategies for biomedical applications. Wearable ultrasound devices can seamlessly conform to human skin or organ surfaces, substantially enhancing working performance, durability, and comfort. Here, we review recent advancements in developing wearable ultrasound devices for biomedical applications, including materials, structural design, and applications in biomedical fields. We provide an overview of wearable ultrasound devices utilized for hemodynamics monitoring, deep-tissue energy transmission, and closed-loop therapy. Finally, we discuss existing challenges and future trends in developing wearable ultrasound devices.
This research successfully developed a fabric sensor with an exceptional linearity and sensitivity based on Ecoflex/carbon composite ink, which holds significant potential for the field of intelligent wearable devices. The sensor's substrate is crafted from woven fabric, selected for its flexibility and breathability, making it an ideal choice for wearable applications. Incorporating Ecoflex/carbon composite ink as a functional material endows the sensor with a favorable linear resistance change rate and ensures its stability. Itis worth noting that the conductive network of the pressure-sensitive layer, made from Ecoflex/carbon composite ink, is firmly embedded within the elastic substrate rather than merely adhered to the fabric surface, thereby conferring superior mechanical strength to the pressure sensor. The fabric sensor exhibits a high linear resistance change rate ( R 2 = 0.9965) across a broad strain range (0%–100%) and maintains remarkable durability after 2000 cycles of cyclic stretching. In terms of application, the intelligent fabric sensor is integrated into a woven glove designed to monitor finger movements to control the navigation between different PowerPoint slides. This innovative application showcases the practicality of intelligent fabric sensors in human–computer interaction, particularly in enhancing the interactivity of presentations and educational settings. The demonstration of this smart glove reflects the sensor's potential applications in wearable electronic devices and paves new directions for the future development of intelligent interactive devices. Equipped with this smart glove, users can interact with electronic devices intuitively and naturally, enhancing operational convenience and opening up new possibilities for the application of innovative wearable technology.
Flexible pressure sensor empowers the perception of external mechanical stimuli with flexible electronics. The adequate alignment between the sensor's operation characteristics and the application scenarios is crucial for maximizing performance. Achieving the configuration of sensitivity and response threshold within single device framework is expected to significantly enhance the versatility of flexible pressure sensor across a variety of applications. In this work, we present a synergistic structural design (SSD) for flexible iontronic pressure sensor to facilitate on-demand configuration of device characteristics. By incorporating a customizable spacer gasket structure and an interlocked microstructure within the ionic gel, the response threshold can be adjusted to cover both small-pressure detection and large operational ranges. With the rational SSD configuration, the SSD-based sensor achieves a sensitivity reaching up to 1478.8 kPa −1 , along with a tunable response threshold from 11.2 Pa to over 400 kPa. We demonstrate the potential of the SSD-based sensor for diverse human interactions applications. Furthermore, a scalable array of the SSD-based sensor units enables multitouch pressure mapping. The SSD approach provides a versatile strategy for tailoring the characteristics of flexible pressure sensor to meet varying application needs.
Locomotive magnetic soft robots have found broad applications in a variety of research fields, such as surgical instrumentation, drug delivery and physical rehabilitation, owing to their rapid responses, ease-of-control and excellent deformability. Many previous reviews have well addressed the material designs and fabrication methods of such branches of soft robots. Apart from the above, structural engineering also plays a vital role in their locomotion capabilities and operational contexts. Therefore, this review focuses on the structure-induced locomotion modes of magnetic soft robots, and classifies them into one-dimensional (1D), two-dimensional (2D), three-dimensional (3D) and fluid-type, according to their structure features. Particularly, specific applications enabled by structure-induced locomotion modes are summarized in detail, revealing closely correlated structure-locomotion-functionality relations. This review also concisely summarizes magnetic components and polymeric matrices used for locomotive magnetic soft robots, and introduces the mainstream fabrication methods, such as molding, additive manufacturing and micro-assembly. Finally, the facing challenges in the relevant research field are discussed and future prospects are provided.
An efficient n-dopant is essential to narrow the metal-organic energy barriers for efficient organic semiconductor optoelectronic devices. Molecular n-dopants feature clear merits of versatile molecular manipulation. However, few can achieve ohmic electron contact due to deficient design strategies. Recent studies have revealed that incorporating strong electron-donating groups (EDGs) not only helps to increase the nucleophilicities and reduce electron affinities of n-dopants, but also facilitates an efficient electron-transfer process by stabilizing the resulting carbocations, thus enabling high n-doping efficiency. A comprehensive review elucidating the underlying physics is imperative for a thorough understanding of how to tune the EDGs precisely, motivating more effective design strategies. Herein, we highlight the conjugative effect as a promising design paradigm for potent n-dopants. This perspective delves into the fundamental principles and latest progress relating to the conjugative effect, culminating in a prospective outlook on the future design strategy of molecular n-dopants for high-performance organic optoelectronics.
