Perovskite-Carbon Nanotube Light-Emitting Fibers

Large-Scale, Stretchable, Self-Protective, and Multifunctional Perovskite Luminescent Filament with Ultra-High Stability

Lead halide perovskites possess great application potential in flexible displays and wearable optoelectronics owing to their prominent optoelectronic properties. However, the intrinsic instability upon moisture, heat, and ultraviolet (UV) light irradiation hinders their development and application. In this work, an ultra-stable CsPbX3 (X = Cl, Br, I) perovskite luminescent filament (PLF) with high stretchability (≈2400%) and luminescence performance (photoluminescence quantum yield (PLQY) of 24.5%, tunable emission spectrum, and high color purity) is introduced by a facile environmental-friendly wet-spinning technology via solvent extraction. Benefiting from the in situ encapsulation of the hydrophobic thermoplastic polyurethane (TPU) and the chelation of Lewis base CO in TPU with Lewis acid Pb2+, the CsPbBr3 PLF demonstrates ultra-high photoluminescence (PL) stability when stored in ambient air and high humidity circumstance, annealed at 50 °C, and dipped in water for 30 days, illuminated under ultraviolet light for 300 min, and immersed in organic solvents and solutions with pH of 1-13 for 5 min, respectively. Impressively, it retains 80% of its initial PL after being recycled five times. Overall, the CsPbX3 PLF demonstrates promising prospects in multifunctional applications, including organic dyes and tensile strain sensing, flexible pattern displays, secondary anti-counterfeiting, and hazard warning systems.

Full-color fiber light-emitting diodes based on perovskite quantum wires

Fiber light-emitting diodes (Fi-LEDs), which can be used for wearable lighting and display devices, are one of the key components for fiber/textile electronics. However, there exist a number of impediments to overcome on device fabrication with fiber-like substrates, as well as on device encapsulations. Here, we uniformly grew all-inorganic perovskite quantum wire arrays by filling high-density alumina nanopores on the surface of Al fibers with a dip-coating process. With a two-step evaporation method to coat a surrounding transporting layer and semitransparent electrode, we successfully fabricated full-color Fi-LEDs with emission peaks at 625 nanometers (red), 512 nanometers (green), and 490 nanometers (sky-blue), respectively. Intriguingly, additional polydimethylsiloxane packaging helps instill the mechanical bendability, stretchability, and waterproof feature of Fi-LEDs. The plasticity of Al fiber also allows the one-dimensional architecture Fi-LED to be shaped and constructed for two-dimensional or even three-dimensional architectures, opening up a new vista for advanced lighting with unconventional formfactors.

Design and fabrication of wearable electronic textiles using twisted fiber-based threads

Mono-dimensional fiber-based electronics can effectively address the growing demand for improved wearable electronic devices because of their exceptional flexibility and stretchability. For practical applications, functional fiber electronic devices need to be integrated into more powerful and versatile systems to execute complex tasks that cannot be completed by single-fiber devices. Existing techniques, such as printing and sintering, reduce the flexibility and cause low connection strength of fiber-based electronic devices because of the high curvature of the fiber. Here, we outline a twisting fabrication process for fiber electrodes, which can be woven into functional threads and integrated within textiles. The design of the twisted thread structure for fiber devices ensures stable interfacing and good flexibility, while the textile structure features easily accessible, interlaced points for efficient circuit connections. Electronic textiles can be customized to act as displays, health monitors and power sources. We detail three main fabrication sections, including the fabrication of the fiber electrodes, their twisting into electronic threads and their assembly into functional textile-based devices. The procedures require ~10 d and are easily reproducible by researchers with expertise in fabricating energy and electronic devices.

LEGO-like Assembly of Fibrous Modules for Display Textiles

Due to their promising advantages over classical rigid devices, the development of display textiles has exciting potential for various fields, including sensor technology, healthcare, and communication. To realize display textiles, it is necessary to prepare light-emitting building blocks at the fiber level and then weave or knit them to form the desired textile structures. However, from a practical viewpoint, it is difficult to continuously weave functional fibers containing light-emitting devices using conventional textile technologies. To address this issue, we introduced fibrous modules that can be assembled like LEGO blocks to realize textile displays. A unique feature of this work is that the light-emitting pixels are generated through a simple contact between modular electrochemiluminescent (ECL) fibers. Each fiber is composed of a single metallic wire coated with a gel-type ECL electrolyte that is formed by using a simple dip-coating method in ambient air. The sticky nature of the gel electrolyte enables the construction of light-emitting pixels through the simple physical contact of two or more fiber modules without the need for external pressure or heating. The diversity of this technology offers in terms of fibrous module arrangements and assembly can provide various options for designing the geometries of light-emitting pixels. We have implemented this technique to demonstrate not only a 1 × 1 pixel but also 3 × 3 pixels with an irregular shape. These results demonstrate that the unique strategy for display devices developed in this work provides a feasible approach for various electronic and optical textile applications.

Electrochemical modification of carbon nanotube fibres

Covalent modification of the surface of carbon nanotube fibres (CNTFs) through electrochemical reduction of para-substituted phenyldiazonium salts and electrochemical oxidation of an aliphatic diamine is described. Following these strategies, diverse surface functionalities have been introduced while preserving the fibre bulk properties. The corresponding modified CNTFs were fully characterised by Raman spectroscopy, X-ray photoelectron spectroscopy, energy dispersive X-Ray, scanning electron microscopy and electrochemical impedance spectroscopy, exhibiting different surface properties from those of the unmodified CNTFs.

Examination of the Effect of RF Field on Fe-MWCNTs and Their Application in Medicine

Carbon nanotubes are a material with excellent properties, which result in a wide range of possible applications, from electronics to medicine. This paper presents the investigation of the possibility of Fe-MWCNTs’ application as heating agents for targeted thermal ablation of cancer cells, which could lead to the development of an innovative cancer treatment method. The article describes the process of synthesis of multi-walled carbon nanotubes filled with iron (Fe-MWCNTs) and provides an examination of their magnetic properties. Fe-MWCNTs were synthesized by catalytic chemical vapor deposition (CCVD). Relevant properties of the nanoparticles in terms of functionalization for biomedical applications were exploited and their magnetic properties were investigated to determine the heat generation efficiency induced by exposure of the particles to an external electromagnetic field. The reaction of the samples was measured for 40 min of exposure. The results showed an increase in sample temperature that was proportional to the concentration.

Water Washable and Flexible Light-Emitting Fibers Based on Electrochemiluminescent Gels

Herein, a new concept of device architecture to fabricate fibrous light-emitting devices is demonstrated based on an electrochemiluminescence (ECL) material for an electronic textile system. A unique feature of this work is that instead of conventional semiconductor materials, such as organics, perovskites, and quantum dots for fibrous light emitting devices, a solid-state ECL electrolyte gel is employed as a light-emitting layer. The solid-state ECL gel is prepared from a precursor solution composed of matrix polymer, ionic liquid, and ECL luminophore. From this, we successfully realize light-emitting fibers through a simple and cost-effective single-step dip-coating method in ambient air, without complicated multistep vacuum processes. The resulting fiber devices reliably operated under applied AC bias of ±2.5 V and showed luminance of 47 cd m^-2. More importantly, the light-emitting fibers exhibited outstanding water resistance without any passivation layers, owing to the water immiscible and hydrophobic nature of the ECL gel. In addition, because of their simple structure, the fiber devices can be easily deformed and woven together with commercial knitwear by hand. Therefore, these results suggest a promising strategy for the development of practical fiber displays and contribute to progress in electronic textile technology.

Washable, Sewable, All-Carbon Electrodes and Signal Wires for Electronic Clothing

Smart wearable electronic accessories (e.g., watches) have found wide adoption; conversely, progress in electronic textiles has been slow due to the difficulty of embedding rigid electronic materials into flexible fabrics. Electronic clothing requires fibers that are conductive, robust, biocompatible, and can be produced on a large scale. Here, we create sewable electrodes and signal transmission wires from neat carbon nanotube threads (CNTT). These threads are soft like standard sewing thread, but they have metal-level conductivity and low interfacial impedance with skin. Electrocardiograms (EKGs) obtained by CNTT electrodes were comparable (P > 0.05) to signals obtained with commercial electrodes. CNTT can also be used as transmission wires to carry signals to other parts of a garment. Finally, the textiles can be machine-washed and stretched repeatedly without signal degradation. These results demonstrate promise for textile sensors and electronic fabric with the feel of standard clothing that can be incorporated with traditional clothing manufacturing techniques.

Fibre electronics: towards scaled-up manufacturing of integrated e-textile systems

The quest for a close human interaction with electronic devices for healthcare, safety, energy and security has driven giant leaps in portable and wearable technologies in recent years. Electronic textiles (e-textiles) are emerging as key enablers of wearable devices. Unlike conventional heavy, rigid, and hard-to-wear gadgets, e-textiles can lead to lightweight, flexible, soft, and breathable devices, which can be worn like everyday clothes. A new generation of fibre-based electronics is emerging which can be made into wearable e-textiles. A suite of start-of-the-art functional materials have been used to develop novel fibre-based devices (FBDs), which have shown excellent potential in creating wearable e-textiles. Recent research in this area has led to the development of fibre-based electronic, optoelectronic, energy harvesting, energy storage, and sensing devices, which have also been integrated into multifunctional e-textile systems. Here we review the key technological advancements in FBDs and provide an updated critical evaluation of the status of the research in this field. Focusing on various aspects of materials development, device fabrication, fibre processing, textile integration, and scaled-up manufacturing we discuss current limitations and present an outlook on how to address the future development of this field. The critical analysis of key challenges and existing opportunities in fibre electronics aims to define a roadmap for future applications in this area.

Electronic fibers and textiles: Recent progress and perspective

Wearable electronics are receiving increasing attention with the advances of human society and technologies. Among various types of wearable electronics, electronic fibers/textiles, which integrate the comfort and appearance of conventional fibers/textiles with the functions of electronic devices, are expected to play important roles in remote health monitoring, disease diagnosis/treatment, and human-machine interface. This article aims to review the recent advances in electronic fibers/textiles, thus providing a comprehensive guiding reference for future work. First, we review the selection of functional materials and fabrication strategies of fiber-shaped electronic devices with emphasis on the newly developed functional materials and technologies. Their applications in sensing, light emitting, energy harvest, and energy storage are discussed. Then, the fabrication strategies and applications of electronic textiles are summarized. Furthermore, the integration of multifunctional electronic textiles and their applications are summarized. Finally, we discuss the existing challenges and propose the future development of electronic fibers/textiles.