Thermally Laminated Lighting Textile for Wearable Displays with High Durability

Alternating current electroluminescence devices: recent advances and functional applications

Wearable smart devices and visualisation sensors based on alternating current electroluminescence (ACEL) have received considerable attention in recent years. Due to the unique properties of ACEL devices, such as high mechanical strength, adaptability to complex environments, and no need for energy level matching, ACEL is suitable for multifunctional applications and visualisation sensing platforms. This review comprehensively outlines the latest developments in ACEL devices, starting with an analysis of the mechanism, classification, and optimisation strategies of ACEL. It introduces the functional applications of ACEL in multicolour displays, high-durability displays, stretchable and wearable displays, and autonomous function displays. Particularly, it emphasises the research progress of ACEL in sensory displays under interactive conditions such as liquid sensing, environmental factor sensing, kinetic energy sensing, and biosensing. Finally, it forecasts the challenges and new opportunities faced by future functional and interactive ACEL devices in fields such as artificial intelligence, smart robotics, and human-computer interaction.

Bright Bifacial White-Light Illumination by Highly Deformable Electroluminescent Devices Based on Transparent Ionic-Hydrogel Electrodes and Quantum-Dot Color Conversion

Deformable alternating-current electroluminescent (ACEL) devices are of increasing interest because of their potential to drive innovation in soft optoelectronics. Despite the research focus on efficient white ACEL devices, achieving deformable devices with high luminance remains difficult. In this study, this challenge is addressed by fabricating white ACEL devices using color-conversion materials, transparent and durable hydrogel electrodes, and high-k nanoparticles. The incorporation of quantum dots enables the highly efficient generation of red and green light through the color conversion of blue electroluminescence. Although the ionic-hydrogel electrode provides high toughness, excellent light transmittance, and superior conductivity, the luminance of the device is remarkably enhanced by the incorporation of a high-k dielectric, BaTiO3. The fabricated ACEL device uniformly emits very bright white light (489 cd m-2) with a high color-rendering index (91) from both the top and bottom. The soft and tough characteristics of the device allow seamless operation in various deformed states, including bending, twisting, and stretching up to 400%, providing a promising platform for applications in a wide array of soft optoelectronics.

Stretchable and Breathable Electroluminescent Displays Based on Ultrathin Nanocomposite Designs

Stretchable electroluminescent devices represent an emerging optoelectronic technology for future wearables. However, their typical construction on sub-millimeter-thick elastomers has limited moisture permeability, leading to discomfort during long-term skin attachment. Although breathable textile displays may partially address this issue, they often have distinct visual appearances with discrete emissions from fibers or fiber junctions. This study introduces a convenient procedure to create stretchable, permeable displays with continuous luminous patterns. The design utilizes ultrathin nanocomposite devices embedded in a porous elastomeric microfoam to achieve high moisture permeability. These displays also exhibit excellent deformability, low-voltage operation, and excellent durability. Additionally, the device is decorated with fluorinated silica nanoparticles to achieve self-cleaning and washable capabilities. The practical implementation of these nanocomposite devices is demonstrated by creating an epidermal counter display that allows intimate integration with the human body. These developments provide an effective design of stretchable and breathable displays for comfortable wearing.

Active Claw-Shaped Dry Electrodes for EEG Measurement in Hair Areas

EEG, which can provide brain alteration information via recording the electrical activity of neurons in the cerebral cortex, has been widely used in neurophysiology. However, conventional wet electrodes in EEG monitoring typically suffer from inherent limitations, including the requirement of skin pretreatment, the risk of superficial skin infections, and signal performance deterioration that may occur over time due to the air drying of the conductive gel. Although the emergence of dry electrodes has overcome these shortcomings, their electrode-skin contact impedance is significantly high and unstable, especially in hair-covered areas. To address the above problems, an active claw-shaped dry electrode is designed, moving from electrode morphological design, slurry preparation, and coating to active electrode circuit design. The active claw-shaped dry electrode, which consists of a claw-shaped electrode and active electrode circuit, is dedicated to offering a flexible solution for elevating electrode fittings on the scalp in hair-covered areas, reducing electrode-skin contact impedance and thus improving the quality of the acquired EEG signal. The performance of the proposed electrodes was verified by impedance, active electrode circuit, eyes open-closed, steady-state visually evoked potential (SSVEP), and anti-interference tests, based on EEG signal acquisition. Experimental results show that the proposed claw-shaped electrodes (without active circuit) can offer a better fit between the scalp and electrodes, with a low electrode-skin contact impedance (18.62 KΩ@1 Hz in the hairless region and 122.15 KΩ@1 Hz in the hair-covered region). In addition, with the active circuit, the signal-to-noise ratio (SNR) of the acquiring EEG signal was improved and power frequency interference was restrained, therefore, the proposed electrodes can yield an EEG signal quality comparable to wet electrodes.

Autonomous Electroluminescent Textile for Visual Interaction and Environmental Warning

Visual interaction is a promising strategy for the externalized expression and transmission of information, having wide application prospects in wearable luminous textiles. Achieving an autonomous luminous display and dynamic light response to environmental stimuli is attractive but attracts little attention. Herein, we propose a liquid responsive structure based on alternating-current electroluminescent fibers and demonstrate conductive-liquid-bridging electroluminescent fabrics with high integration and personalized patterns. Impressively, our electroluminescent fibers and textiles could afford a sensitive response and high robustness to water, glycerol, ethanol, and sodium chloride solution. The final electroluminescent textiles show an excellent luminescence performance of 149.08 cd m-2. On the proof of concept, a rain-sensing umbrella, luminous sportswear, and liquid response glove are fabricated to demonstrate water detection, visual interaction, and environmental warning. The textile-type visualizing-responding strategy proposed in this work may open up new avenues for the application of ACEL devices in the field of visual interaction.