npj Flexible Electronics最新文献

Underactive bladder (UAB) patients experience straining to void and typically cannot sense bladder fullness. Previous closed-loop bladder volume control systems are limited in neurogenic UAB patients and face infection risk due to wired connections. Here, we propose an intelligent bladder volume control system (IBCS) combining an implantable meshed magnetic soft robot (MMR) with a wearable magnetic field sensor. The MMR, tightly sutured to the bladder, compresses the bladder to facilitate urination under magnetic actuation, achieving a voiding efficiency of 94.8%. The wearable magnetic field sensor outside the abdomen achieves continuous and wireless monitoring of bladder volume with a 4.8% error in time. The MMR was validated on a UAB pig model, demonstrating a pressure increase of up to 33 cmH₂O and voiding efficiency of over 83%. Our IBCS provides a biocompatible solution for wireless and continuous bladder volume management by integrating wearable sensors and magnetic robotics.

Significant progress has been made in perovskite light-emitting diodes (PeLEDs) over the past decade, with external quantum efficiencies (EQEs) exceeding 30% for green and red emissions, and 20% for blue emissions. However, the performance and device area of flexible PeLEDs remains constrained due to issues such as crack formation and short circuits that occur during device deformation. These challenges limit their applicability in flexible, stretchable, and wearable displays and lighting solutions. This review systematically summarizes recent advancements in flexible PeLEDs, focusing on various strategies to improve their flexibility and performance. We first discuss the use of flexible substrates and electrodes in these devices. Next, we examine the fabrication methods and the mechanical and optoelectronic properties of different perovskite materials used in flexible PeLEDs, including three-dimensional (3D) thin films, low-dimensional nanomaterials, and perovskite/polymer composites. Finally, we highlight the extensive applications of flexible PeLEDs in wearable optoelectronics and provide an outlook on the future development of high-performance flexible PeLEDs to facilitate their commercialization.

Owing to unique advantages of patternability and high substrate compatibility, screen-printing allows for the fabrication of flexible perovskite solar cells (f-PSCs) with designable device patterns, while the defective and fragile contact at the buried interface seriously restricted the device performance. Herein, a series of siloxane coupling agents (SCAs) with different ending groups i.e., –SH, –NH₂, and –CN were incorporated at the SnO₂/perovskite interface, which can selectively interact with MA⁺ and Pb²⁺ via hydrogen and coordination bonding, respectively. It was revealed that the selection of (3-Cyanopropyl)Triethoxysilane (CN-PTES) can regulate perovskite crystallization with accelerated nucleation and retarded crystal growth, leading to improved crystallinity with released residual lattice strain. Moreover, the incorporated CN-PTES aligned the energy structure of the underlying SnO₂ and boosted the interfacial adhesion between perovskite and SnO₂, resulting in facilitated electron extraction and enhanced interfacial fracture energy. Consequently, the first screen-printed f-PSCs with improved mechanical resistance were finally obtained.

Transparent electro-optical neural interfacing technologies offer simultaneous high-spatial-resolution microscopic imaging, and high-temporal-resolution electrical recording and stimulation. However, fabricating transparent, flexible, and mechanically robust neural electrodes with high electrochemical performance remains challenging. In this study, we fabricated transparent (72.7% at 570 nm), mechanically robust (0.05% resistance change after 50k bending cycles) ultrathin Au microelectrodes for micro-electrocorticography (µECoG) using a hexadentate metal-polymer ligand bonding with an EDTA/PSS seed layer. These transparent µECoG arrays, fabricated with biocompatible gold, exhibit excellent electrochemical properties (0.73 Ω·cm²) for neural recording and stimulation with long-term stability. We recorded brain surface waves in vivo, maintaining a low baseline noise and a high signal-to-noise ratio during acute and two-week recordings. In addition, we successfully performed optogenetic modulation without light-induced artifacts at 7.32 mW/mm² laser power density. This approach shows great potential for scalable, implantable neural electrodes and wearable optoelectronic devices in digital healthcare systems.

Correction to: npj Flexible Electronics https://doi.org/10.1038/s41528-024-00375-3, published online 04 January 2025

Conductive fibers are essential for wearable electronics, especially in electronic textiles (e-textiles) used as skin-interfaced sensors and interconnects. Achieving sustainable e-textiles with integrated toughness, waterproofing, and washability remains challenging. We present waterproof conductive tough fibers (CTFs) fabricated via a scalable, continuous capillary tube-assisted coating (CTAC) process. The multilayered CTFs demonstrate a conductivity of 6.42 kS/cm, Young’s modulus of 6.22 MPa, toughness of 9.40 × 10⁵J/m³, and 70% strain at break. With lengths exceeding 20 m, a native oxide layer on the eutectic gallium-indium (EGaIn) shell ensures reliable waterproofing with the IPX8 standard. They also maintain consistent performance for 24 days water immersion and repeated washing up to 100 cycles, showing superior resistance retention compared to the EGaIn-absence fibers. As a proof-of-concept, they enable wireless power transfer and reliable monitoring of electrocardiogram and electromyogram signals, establishing a robust platform for sustainable e-textiles.

The advancement of wireless communication raises the demand for flexible, high-performance RF antennas for wearable electronics and flexible communication devices. Traditional approaches focused on reducing the thickness of metal films to enhance flexibility which faces limitations due to the skin effect. Herein, a hybrid graphene-Au nanomembrane is produced by one-step delamination processes to address the limitations of traditional metal films, including flexibility and RF functionality. The graphene-Au nanomembrane features a bond-free van der Waals interface, allowing the Au layer move freely with graphene. This structure mitigates the formation of cracks, enhancing the stretchability to over 14% strain and fatigue resistance. Moreover, this composite overcomes the limitations associated with skin depth, consequently enabling an ultra-thin graphene-Au antenna operating at 8.5 GHz for 5 G communications. We also demonstrate wireless image transmission and electromagnetic stealth. The results underscore the significant impact of the innovative design and materials on flexible wireless technology.

Health monitoring with wearable pulse oximetry (PO) paves the way for personalized, point-of-care health management. Organic PO (OPO) sensors are particularly promising for wearable POs due to their excellent compatibility with flexible, lightweight form factors and design freedom, enabling low power consumption comparable to or even surpassing that of conventional inorganic systems. However, further power reductions are crucial for wearable systems with limited onboard power, and achieving sufficient signal strength at minimal luminance is essential for extended operation. Here, we propose an OPO structure with both ultralow power consumption and low luminance operation. By combining a ring-shaped, vertically stacked two-color organic light-emitting diode (OLED) with a circular organic photodiode (OPD) filling the interior and exterior of the OLED ring, we demonstrate OPO sensors requiring only a few μW to drive the OLEDs and operable at a few tens of cd/m², demonstrating potentials for continuous health monitoring with extended long-term operation.

Cyborg insects are living organisms combined with artificial systems, allowing flexible behavioral control while preserving biological functions. Conventional control methods often electrically stimulate sensory organs like antennae and cerci but these invasive methods can impair vital functions. This study shows a minimally invasive approach using flexible, ultra-thin electrodes on the cockroach’s abdomen, avoiding contact with primary sensory organs. Using liquid evaporation for film adhesion provides a biocompatible process with excellent adhesive strength and electrical durability. Body surface stimulating component structures formed by utilizing an insect’s natural movement showed higher stability than conventional methods. These enable effective control of both turning and straight-line movements. This minimally invasive method maintains the insect’s natural behavior while enhancing cyborg functionality, extending the potential applications.

Flexible electronics demand multifunctional human-machine interfaces (HMIs) and organic user interfaces (OUIs). Existing deformable displays often rely on mechanical wires or hinges, limiting their thinness and flexibility. Incorporating sound features typically requires extra components, complicating design. In this study, we developed a lightweight, multifunctional display with a multi-shape bendable design and integrated sound capabilities. Using asymmetrical strain engineering on poly(vinylidene fluoride) (PVDF), we achieved bidirectional and complex deformations through electrical signals, eliminating the need for mechanical hinges. The PVDF actuator enables simultaneous sound emission and intricate shape transformations through rapid actuation and vibration. This design maintains the thinness and flexibility of organic light-emitting diode (OLED) technology. By controlling strain through PVDF polarization and applied electric field, we realized varied shape transformations and integrated these functions into a practical 6-inch OLED display. This approach enhances the functionality of flexible displays, expanding possibilities for future applications in flexible electronics.