2025-10-31 2025, Volume 2 Issue 3

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  • ARTICLE
    Soon Poh Lee, Kwok Feng Chong, Eng Hock Lim, Chun Hui Tan, Cao Guan, Pei Song Chee
    2025, 2(3): 290-302. https://doi.org/10.1002/flm2.70001

    Fabric-based energy storage devices are essential for next-generation wearable electronics, requiring materials that combine lightweight structure, high conductivity, and mechanical durability. Laser-induced graphene (LIG) is a promising candidate due to its tunable surface chemistry, excellent electrical properties, and compatibility with textile substrates. However, improving its electrochemical performance often involves chemical modifications with metal oxides or polymers, complicating processing and limiting scalability. Traditional synthesis methods for oxygen-rich graphene rely on hazardous chemicals and labor-intensive procedures. In this work, we present an eco-friendly, one-step laser-scribing technique to fabricate oxygen-functionalized LIG directly on Kevlar textiles, enabling the creation of flexible, fabric-based energy storage devices without the need for chemical treatments. By carefully controlling the laser power (P) and scan speed (S), we achieve a precise balance between graphitization and oxygen functionalization. Density functional theory analysis reveals that specific oxygen groups—carboxyl, hydroxyl, epoxy, and carbonyl—play a key role in enhancing potassium-ion adsorption. The optimized LIG-P3S1 sample (laser power level 3, scan speed level 1) exhibits a high carbon content of 89.12 At%, with 67.51% of oxygen groups from C–O and C–OH bonds. This surface chemistry results in an areal capacitance of 88.92 mF cm−2 at 0.3 mA cm−2, along with good cycling stability, retaining 66.67% capacitance after 10 000 cycles. The device also demonstrates stable performance under bending angles of up to 120°, making it suitable for wearable applications. This work offers a scalable, sustainable approach to flexible energy storage, with potential applications in wearable and biomedical electronics.

  • ARTICLE
    Xu-Feng Luo, Jun-Yi Wang, Cong Wang, Chao Deng, Xunwen Xiao, You-Xuan Zheng
    2025, 2(3): 303-311. https://doi.org/10.1002/flm2.70002

    Multi-resonance thermally activated delayed fluorescence (MR-TADF) emitters have shown promise for achieving full-color emission with a high efficiency and a narrow band. However, the development of MR-TADF materials with both high efficiency and deep-blue emission for organic light-emitting diode (OLED) remains a significant challenge. Herein, a B/N-based MR core and a indolocarbazole group are interlocked in 3D mode to induce intramolecular interaction between both, culminating in the development of the target emitter, DPABN-ICz. Notably, DPABN-ICz demonstrates a remarkable deep-blue emission, peaking at 445 nm, with a small full width at half maximum (FWHM) of 19 nm and a Commission Internationale de L'Eclairage (CIE)y coordinate of 0.06. Interestingly, DPABN-ICz exhibits an enhanced oscillator strength of 0.2975, resulting in an impressive photoluminescence quantum yield of 94%. Furthermore, the sensitized OLED achieves a high maximum external quantum efficiency of 31.4%, and a narrow electroluminescence with a small FWHM of 27 nm and the CIE coordinates of (0.153, 0.055), closely aligning with the BT.2020 deep-blue emission standard.

  • REVIEW
    Yili Wang, Yunqi Liu, Yunlong Guo
    2025, 2(3): 312-340. https://doi.org/10.1002/flm2.70006

    With the rapid development of human-computer interaction and Internet of Things technologies, bioinspired electronics have attracted significant attention due to their excellent compatibility, portability and mechanical flexibility. Over the past few decades, advancements in stretchable organic semiconductor materials and devices have established stretchable organic transistors as versatile platforms for bioinspired electronic systems, owing to their exceptional mechanical stretchability, high biocompatibility, and tunable optoelectronic properties. These devices, with their multifunctionality to simultaneously process and store information, effectively circumvent the von Neumann bottleneck, thereby driving the development of next-generation bionic intelligence, artificial sensory systems, and neuroprosthetics. In this review, we first provide a comprehensive overview of recent advances in design strategies for stretchable organic transistors, encompassing design of intrinsically stretchable materials and structural engineering approaches. Next, we summarize their applications in bioinspired electronics, particularly in neuromorphic devices and skin-like sensors. Finally, we discuss the prospects and challenges of stretchable organic transistor-based bioinspired electronics, ranging from the design of intrinsically stretchable organic materials to their practical implementation, thereby laying a solid foundation for next-generation prosthetic skins, human-machine interfaces, and neurorobotics.

  • REVIEW
    Jiayu Pan, Wenbin Zhao, Yukai Zhou, Jing Wu, Wen Cheng, Yi Shi, Lijia Pan
    2025, 2(3): 341-364. https://doi.org/10.1002/flm2.70010

    Conformal electronics integrate mechanically compliant materials with advanced fabrication strategies, enabling devices to mount seamlessly onto non-planar, dynamic, and even biological surfaces. In these scenarios, such systems deliver enhanced measurement accuracy, improved stability, and greater adaptability and comfort compared to rigid counterparts, thereby redefining the frontiers of wearable technology. In this review, we first focus on strategies and fabrication technologies for achieving conformability, and applications in fields such as healthcare, consumer electronics, and industry. Then we discuss current challenges, such as scalability and durability, while exploring future research directions in material innovation and process optimization. Finally, we provide a comprehensive understanding of conformal flexible thin film devices, charting a path for future advancements.

  • REVIEW
    Yunqi Lin, Yuezhong Huang, Tianyue Wang, Songhua Cai, Yujie Wu, Lihua Li, Zhongmin Yang, Jiewei Chen
    2025, 2(3): 365-389. https://doi.org/10.1002/flm2.70007

    Flexible photonic sensing chips (FPSCs) have emerged as a promising class of devices that integrate optical sensing capabilities with mechanically compliant materials, offering unique advantages such as stretchability, biocompatibility, and electromagnetic interference resistance. These features make them particularly suitable for next-generation wearable technologies aimed at continuous, non-invasive multiparameter health monitoring. In recent years, significant progress has been achieved in material engineering, device architecture, and fabrication techniques, enabling flexible photonic chips to achieve high sensitivity, low detection limits, and robust performance under mechanical deformation. Notably, bioinspired design strategies - mimicking the structural and functional characteristics of biological visual and tactile systems - have been increasingly employed to enhance sensing precision and environmental adaptability. This review provides a comprehensive overview of the fundamental principles, materials, and manufacturing processes of FPSCs, followed by an in-depth discussion of their applications in wearable and implantable health monitoring systems.

  • REVIEW
    Weiwei Li, Chunbo Duan, Ying Wei, Hui Xu
    2025, 2(3): 390-419. https://doi.org/10.1002/flm2.70012

    The brain orchestrates complex physiological processes through intricate neural networks, with synapses serving as the fundamental units for inter-neuronal communication and ensuring the efficient functioning of these networks. Consequently, the development of devices capable of emulating synaptic functions represents a crucial avenue for advancing our understanding of neural networks. Among these devices, memristors have emerged as a promising candidate. Recognized as the fourth fundamental passive circuit element, memristors exhibit distinctive nonlinear memory characteristics. Their resistance values dynamically adjust in response to variations in the charge flowing through them and, importantly, retain these modified states even after power disconnection. These unique properties render memristors particularly suitable for emulating synaptic functions in neural systems. This paper provides a comprehensive overview of recent advancements in material selection and resistive switching mechanisms for flexible memristors, highlighting their applications in the construction of artificial neural networks. Furthermore, we discuss the feasibility of implementing neural networks using memristor-based architectures, while also addressing the current challenges that need to be overcome. Finally, we outline the development prospects and ongoing challenges in this rapidly evolving field.

  • REVIEW
    Linbo Feng, Shuai Yang, Chenyang Zha, Yao Yin, Lin Wang
    2025, 2(3): 420-441. https://doi.org/10.1002/flm2.70000

    Two-dimensional (2D) semiconductors offer unique advantages for light-emitting diodes (LEDs) due to their atomic-scale thickness, strong excitonic effects, tunable band structures, and compatibility with Van Der Waals heterostructures. These properties enable fine control over carrier injection, exciton recombination, and light–matter interactions, facilitating functionalities not easily achieved in bulk semiconductors. This review provides a comprehensive overview of 2D material-based LEDs, with emphasis on device architectures, performance modulation, and emerging applications. Key configurations, such as p–n junctions, Schottky contacts, and quantum well heterostructures, are examined in terms of charge transport and emission behavior. Strategies to tailor emission properties are discussed, focusing on band structure engineering, interface optimization, and photonic field control. Additionally, unique electroluminescence phenomena arising from spin–valley coupling, in-plane anisotropy, and multi-exciton dynamics are highlighted, enabling polarized, valley-resolved, and dynamically tunable emission. These capabilities open up opportunities for integration into quantum light sources, neuromorphic vision, and reconfigurable photonic platforms. To advance toward practical applications, improvements are needed in spectral tunability, light-extraction efficiency, and scalable fabrication. Continued progress in materials synthesis, device engineering, and photonic integration is expected to accelerate the development of high-performance, application-oriented 2D optoelectronic systems.

  • COMMUNICATION
    Xueting Jiao, Yueqi Wang, Rongze Zhu, Yuwei Chen, Jiajun Pan, Zhenzhong Lu, Xiao-Chun Hang, Zhengyi Sun, Wei Huang
    2025, 2(3): 442-451. https://doi.org/10.1002/flm2.70009

    Lighting sources resembling sunlight with less blue hazards are desirable in today's world. Herein, we present a strategy for constructing low-energy white organic light-emitting diodes (WOLEDs) consisting of blue and yellow emissive layers (EMLs). Two new Pt (II) complexes, PtA-Y and PtB-Y, were developed as super broad-spectrum yellow emitters featuring dual-emission bands. The yellow OLEDs incorporating the broad-spectrum emitter were adjusted to fully cover the region from green to deep red with the full-width of half maximums over 150 nm. By adding the complementary blue EML, WOLEDs achieved a high color-rendering index of 95 at a correlated color temperature of 3767 K with less blue but more deep red emission, minimal color shift with the Commission Internationale de l’Elcairage coordinates shift CIE(Δx,Δy) of (0.008, 0.001) in the luminance range of 178∼1168 cd m−2, and long device operational half lifetimes over a hundred hours at 1000 cd m−2. The strategy of constituting high-color-quality WOLEDs demonstrated here may assist the development of healthy lighting sources, feasibly having healing functions of flexible profile in the future.