npj Flexible Electronics最新文献

Mimicking and extending biological sensory memory processing functions and systems—that play significant roles in enhancing interconnections of the human-physical world—are highly preferable for the Internet of Things. However, conventional artificial sensory systems usually consisted of separated modules or relied on perception-memory-processing devices with applications in a limited domain. Here, we propose a self-rectifying multifunctional synapse based on a unique PN optoelectrical memristor interface, achieving an augmented artificial visual system and multifunctional interconnected ports. The synapse realizes in-sensor motion perception and non-contact control beyond perception-memory-processing functions. The self-rectifying device can self-suppress the sneak current in cross-arrays, enabling large-scale and high-density integration. Further integrating synapse with quantum dot light-emitting diodes (QLEDs) evolves more powerful functions like hardware noise filtering and perception-memory-processing-displaying smart systems.

The increasing demand for adaptable, lightweight, and efficient pump systems in engineering and medical fields highlights the limitations of traditional rigid pumps, which are bulky, noisy, and inflexible. Despite advancements in smart materials and electro-hydrodynamics (EHD), flexible pumps face challenges from structural rigidity and performance constraints. Here, we develop a customizable soft fiber pump (CSFP) that utilizes wound printed flexible electrodes alongside thermoplastic tubes. This innovative approach enables variable electrode configurations, tunable internal diameters, and modifiable cross-sectional geometries, significantly enhancing the pump’s performance and adaptability. The fabrication method yields a compact structure with intergrated electrodes, reconfigurable cross-sections, and flow orientation control. With these features, the CSFP achieves a pressure gradient of 1.39 kPa/cm and a specific flowrate of 160 mL/min/g. These capabilities support its use in soft actuation, conformal thermal management, and redirected flow for impurity separation, demonstrating potential for integration into a broad range of technological and industrial applications.

This paper provides a comprehensive review of the research progress in paper-based flexible electronic devices, focusing on key aspects such as the physical and chemical properties of paper substrates, device structures, fabrication methods for electrodes and active layers, and their diverse applications. The paper also identifies current challenges facing paper-based electronic devices, such as issues related to long-term stability and the optimization of large-scale production processes.

Reverse-offset printing (ROP) enables microscale patterning on flexible substrates, making it ideal for fabricating interdigital capacitive (IDC) sensors for atopic dermatitis (AD) monitoring. AD, characterized by skin dryness and inflammation, demands precise hydration tracking. Tailoring IDC electrode gaps to 50 µm concentrates the electric field within the stratum corneum (SC), enhancing sensitivity beyond the capabilities of traditional screen printing. Finite element modelling and ROP were employed to assess the impact of electrode geometry and encapsulation thickness on sensor performance. Findings indicate that 50 µm electrodes with encapsulation layers under 10 µm maintain high sensitivity and consistent operation. A clinical case study demonstrated the 50 µm sensor’s ability to distinguish lesional from non-lesional skin. These results inform the optimization of encapsulation–performance balance and advance the design of wearable, high-resolution IDC sensors for continuous skin hydration monitoring in personalized dermatological care.

Electrodes underpin electrophysiological signals recording, requiring stable skin contact and low impedance for high-quality, long-term acquisition. Dry microneedle electrodes penetrate the stratum corneum and bypass hair to ensure robust contact, but conventional rigid designs lack tissue conformity, risking discomfort and injury. This work introduces a modulus-adjustable, mechanically adaptive dry microneedle electrode (MDME) constructed from PEDOT: PSS and shape memory polymer. Submillimeter MDME penetrates skin barriers and, upon body temperature activation, softens to match tissue mechanics, minimizing invasiveness. The MDME exhibits low, stable interface impedance and enables high-quality electromyography, electrocardiography, electroencephalography, and electrocorticography recordings. After one month of usage, the electrophysiological root mean square noise increased by only 6 μV, compared to 63 μV of Ag/AgCl gel electrodes. Electroencephalogram signal-to-noise reached 8.12 dB versus 7.26 dB for the cranial screw electrodes. This work represents a notable advancement in MDME-based electrophysiological recording, expanding its potential applications in personalized healthcare and human-machine interaction.

Stretchable and flexible electronics represent emerging and exciting directions for future electronics, while transfer printing plays an essential and mainstream role in integrating electronics onto application substrates. However, existing transfer printing approaches have restrictions for electronics in terms of stiffness and dimensionality, as well as limitations for substrates in terms of surface and adhesion. Here, we report a versatile soap bubble transfer printing technique that, through a volume modulation strategy, enables the adhesion-independent, damage-free, and low-contamination integration of rigid, flexible, and three-dimensional curved electronics onto substrates with complex surfaces and challenging adhesion. To demonstrate the versatility and compatibility of the soap bubble transfer printing technique, we performed not only special behaviors such as wrap-like, multilayer, selective, and interior printing, but also integrated flexible electronics onto various human organ models, which holds promise for health monitoring in both noninvasive and invasive manners.

Flexible sensing array integrated with multiple sensors is an attractive approach for flight parameter detection. However, the poor resolution of flexible sensors and time-consuming neural network processes mitigate their accuracy and adaptability in predicting flight parameters. Here we present an ultra-thin flexible sensing patch with a new configuration, comprising a differential pressure sensor array and a vector flow velocity sensor. The capacitive differential pressure sensor array is fabricated by a multilayer polyimide bonding technique, reaching a resolution of 0.14 Pa. To solve flight parameters with the flexible sensing patch, we develop an analytical pressure-velocity fusion algorithm, enabling fast response and high accuracy in flight parameter detection. The average errors in calculating the angle of attack, angle of sideslip, and airspeed are 0.22°, 0.35°, and 0.73 m s⁻¹, respectively. The high-resolution flexible sensors and novel analytical pressure-velocity fusion algorithm pave the way for flexible sensing patch-based air data sensing techniques.

Organic electrochemical transistors (OECTs) based on poly(3,4-ethylenedioxythiophene) (PEDOT) have been extensively studied, yet devices fabricated via electropolymerization remain underexplored in terms of the underlying ionic dynamics and the potential for flexible integration. In this work, we demonstrate robust OECTs based on electropolymerized PEDOT, exhibiting negligible drain current degradation after 1000 cycles of operation in aqueous NaCl. Compared to inkjet-printed devices, they offer markedly superior cycling stability, which is further enhanced by the incorporation of the small anionic dopant ClO₄⁻. We also show flexible, lightweight OECTs by electropolymerizing PEDOT on ultrathin parylene substrates, achieving stable performance under mechanical strain. Furthermore, Electrochemical Quartz Crystal Microbalance with Dissipation (EQCM-D) analysis reveals distinct ion transport behavior in PEDOT:ClO₄, where dopant ejection dominates doping/dedoping process, unlike in PEDOT:PSS. This study underscores the advantages of electropolymerization and small-ion doping, offering new mechanistic insights and advancing the design of high-performance, flexible OECTs for bioelectronic applications.

Triboelectricity-driven acoustic transducers with various merits have demonstrated significant potential in energy harvesting and self-powered sensing. The transducers generally require additionally a spacer and a corresponding exquisite process for smooth operation, which provides an unnecessary interface between the elements. The exploration of a novel manufacturing approach for triboelectricity-driven acoustic transducers is warranted to resolve this issue. Here, Triboelectricity-driven Oscillating Nano-Electricity generator (TONE) developed via mechanically guided four-dimensional (4D) printing is introduced for acoustic energy harvesting and self-powered voice recognition. The mechanically buckled structure of the TONE facilitates its smooth oscillation by sound wave without the use of an additional spacer, enabling the TONE to exhibit outputs of 156 V and 10 μA. The output characteristics of the TONE are analyzed based on the acoustic-structural-triboelectric interaction mechanism. The TONE demonstrates practical versatility by providing power to commercial electronics from controlled/daily sound and being utilized in artificial intelligence-based human voice recognition sensors.

Integrating surface-mounted devices (SMDs) onto textiles remains a key challenge in wearable electronics due to textile surface irregularities and heat sensitivity. Conventional methods like soldering or anisotropic conductive films (ACFs) often fail in such environments. We introduce a low-stress anisotropic conductive adhesive (LS-ACA) composed of eutectic gallium–indium (EGaIn) liquid metal particles (LMPs) embedded in a pressure-sensitive SIS matrix. LS-ACA offers excellent electrical conductivity, mechanical flexibility, and durability under bending, stretching, and crumpling. Finite element analysis shows it reduces interfacial stress concentrations compared to soldering, maintaining uniform stress even under 10% strain. It achieves ultra-low contact resistance (1.5 mΩ at >64 wt% LMPs) and enables low-temperature bonding on diverse substrates. Moreover, LS-ACA supports over 10 reuse cycles without surface damage or performance loss. This scalable, reusable material offers a promising path for integrating electronics into fabrics, advancing sustainable and flexible wearable technologies.