Ga₂O₃ is a leading candidate for next-generation high-power electronics and deep-ultraviolet optoelectronics due to its ultrawide bandgap and high theoretical breakdown field. While the stable β-phase has been extensively studied, interest is shifting toward metastable polymorphs to broaden functionality. Among these, the ε/κ phase is distinguished by its non-centrosymmetric orthorhombic structure, offering unique ferroelectric and piezoelectric properties. Despite progress in epitaxial stabilization, a comprehensive understanding of its crystal structure, physical behavior, and device potential remains limited. This review critically examines the ε−κ phase relationship and heteroepitaxial growth mechanisms on Al₂O₃, GaN, and other substrates, highlighting the roles of supersaturation, doping, and buffer layer engineering in stabilizing metastable phases while suppressing secondary phases. Furthermore, the work explores the unique physical properties of ε/κ-Ga₂O₃, including the substantial spontaneous polarization, a large piezoelectric coefficient, and the direct-bandgap nature favorable for DUV detection. The practical efficacy of these attributes is showcased across a diverse technological portfolio, including ferroelectric memristors for neuromorphic computing, high-frequency acoustic wave resonators, and high-sensitivity solar-blind photodetectors. Finally, the review identifies remaining challenges-such as rotational domain mitigation and polarization saturation-providing a strategic roadmap for realizing multifunctional ε/κ-Ga₂O₃-based devices.

Two-dimensional (2D) van der Waals (vdW) materials offer atomically thin, dangling-bond-free interfaces and strong electrostatic control characteristics, enabling a new paradigm for optoelectronic devices. This review focuses on vdW contact engineering and heterostructure construction. The vdW contact can suppress Fermi-level pinning, reduce contact resistance, and preserve the intrinsic properties of 2D semiconductors. Leveraging such clean interfaces, 2D vdW materials show great potential in implementing functional devices, including photodetectors, miniaturized computational spectrometers, reconfigurable devices, and neuromorphic systems. In these cases, the tunable vdW interfaces eliminate lattice-matching constraints and allow feasible heterogeneous integration. This review discusses the recent progress and future prospects in this field, providing guidance for realizing functional applications based on vdW device configuration.

Low-dimensional metal-halide perovskites have emerged as promising materials for optoelectronic synapses and neuromorphic vision systems owing to their strong light–matter interactions, tunable optoelectronic properties, and mixed ionic–electronic transport. Compared with three-dimensional counterparts, low-dimensional perovskites exhibit more powerful control over charge transport, ion migration, and optical absorption with enhanced stability. In this review, we outline the composition, dimensionality, and growth strategies of low-dimensional perovskites, emphasizing how structural engineering governs their optical and electrical properties. Their photodetection, memristive, and photo-reservoir behaviors are further discussed to form physical foundation for light-stimulated synaptic functions, including optical sensing, memory retention, and conductance modulation. We review representative optoelectronic synapses based on 0D, 1D, and 2D perovskites according to their device-level mechanisms, highlighting how dimensionality enables distinct visual functions and device architectures. Exemplary neuromorphic algorithms are discussed as well, including artificial neural networks, convolutional neural networks, spiking neural networks, recurrent neural networks, and reservoir computing, which translate perovskite synaptic responses into higher-level capabilities such as image recognition, multimodal perception, and motion detection. Finally, we catalog the remaining challenges including lead toxicity, limited lead-free performance, crystallization and device-to-device variations, ion-migration-induced instability, and options for wafer-scale patterning and addressable integration. By connecting materials design, synaptic device physics, neuromorphic algorithms, and scalable integration strategies, with perspectives on how low-dimensional perovskites can evolve from laboratory-scale optoelectronic synapses into practical platforms for next-generation artificial vision systems.

Electromyography (EMG) is widely used in sports rehabilitation to evaluate muscle activation, coordination, fatigue, and functional recovery, yet reliable recording remains limited by the electrode-skin interface during repeated motion and prolonged wear. Microneedle electrodes offer a distinct interface strategy by penetrating the stratum corneum and forming lower-impedance, more stable electrical contact than conventional wet or dry electrodes. This review discusses microneedle electrodes for EMG acquisition in sports rehabilitation from a design-to-application perspective. We first clarify the interface requirements of EMG recording in rehabilitation settings and the technical rationale for using microneedle interfaces. We then summarize material and structural design strategies in silicon-, polymer-, and metal-based systems, focusing on how they balance penetration capability, mechanical compliance, stretchability, conductivity, and recording stability. Fabrication routes are further examined in terms of material-structure-process coupling, followed by applications in static assessment, dynamic motion monitoring, and clinical rehabilitation evaluation. This review integrates interface requirements, design, manufacturing, and validation to provide a structured overview of microneedle EMG electrodes' capabilities and limitations for sports rehabilitation.

The integration of proximity sensing into flexible tactile electronic skins (e-skins) represents a fundamental shift from conventional contact-only interfaces toward anticipatory perception systems. This mini-review provides a systematic examination of recent advances in proximity-augmented e-skins, which overcome the inherent latency of tactile sensors by extending sensory awareness into the pre-contact domain. We provide a comprehensive overview of five key sensing modalities—capacitive, triboelectric, magnetic, temperature-based, and humidity-based—detailing their operating principles, material innovations, and structural optimization strategies. System-level requirements for practical deployment are also critically analyzed. Representative applications in interactive surfaces, human–robot collaboration, soft robotics, healthcare monitoring, and integrated multifunctional e-skins are highlighted to illustrate the transformative potential of this technology. Despite substantial progress, challenges persist in seamless multimodal integration, scalable manufacturing, and intelligent data fusion. Future directions are discussed to realize robust, perceptually intelligent e-skins that bridge the gap between laboratory innovations and real-world applications.

Organic electrochemical transistors (OECTs), leveraged by their unique volumetric doping mechanism and ultra-high transconductance performance, have emerged as a pivotal device platform for constructing high-performance bioelectronic interfaces. OECT-based theranostics aim to develop intelligent closed-loop systems that integrate sensing, decision-making, and execution, thereby overcoming the latency and discretization limitations of traditional medical models when managing dynamic physiological fluctuations. This article systematically reviews the performance evolution of OECT materials from p-type to n-type, discusses critical strategies for enhancing device stability and transconductance density, such as side-chain engineering and ladder-type molecular design, while emphasizing the essential role of complementary logic circuits in minimizing the static power consumption of implantable electronics. Furthermore, breakthroughs in OECT-based neuromorphic computing are addressed; by simulating synaptic plasticity (STP/LTP) and engineering organic electrochemical neurons (OECNs), a highly efficient sensing-computing closed-loop architecture has been realized. The current application landscape of OECTs in electrophysiological monitoring, neurochemical sensing, and multimodal synergistic sensing is detailed, alongside a summary of high-density array fabrication and system integration strategies, including 3D printing, inkjet printing, and 3D hydrogel integration. Finally, future outlooks are provided, focusing on challenges such as the environmental stability of n-type materials, multimodal signal crosstalk, and long-term clinical reliability.

Ion-migration memristive synaptic devices provide a physical route for hardware neuromorphic computing by using ionic redistribution, conductive-filament evolution, and interfacial barrier modulation to regulate synaptic weights. However, existing studies are often discussed according to specific material systems or individual device demonstrations, which makes it difficult to compare how different ion-migration mechanisms determine synaptic behavior, device stability, and integration potential. This mini review organizes recent progress from the perspective of operating mechanism and device type. Electrochemical metallization (ECM)-based synaptic devices are discussed with emphasis on metallic-filament formation and the challenge of achieving gradual and reproducible conductance modulation. Filamentary valence-change memory (VCM)-based devices are reviewed in terms of oxygen-vacancy channel evolution, while interfacial VCM devices are examined through interfacial ionic modulation and barrier-controlled analog switching. Hybrid ECM-VCM devices are further discussed as integrated designs that couple multiple ionic processes to balance switching window, stability, and multifunctionality. By linking mobile ionic species, switching pathways, and synaptic functions, this review provides a mechanism-based framework for understanding ion-migration memristive synaptic devices and for identifying the material, interface, and device-level issues that remain before scalable neuromorphic hardware can be realized.

With the rapid development of the Internet of Things (IoT) and wearable electronics, tactile sensors play an indispensable role in intelligent sensing systems. However, traditional tactile sensing systems follow the von Neumann architecture, where sensors and processing units are physically separated. This leads to frequent data transfer of large raw data volumes, causing high latency and energy consumption. Such bottlenecks cannot meet the requirements of real-time closed-loop control and edge intelligence. Inspired by the highly integrated "perception-storage-computation" mechanism of biological sensory systems, memristor-based neuromorphic computing offers a groundbreaking solution beyond conventional approaches. Memristors combine non-volatile storage with tunable resistance. They enable in-situ emulation of synaptic plasticity, in-memory computing, and brain-inspired processing, thereby holding the potential to significantly improve the energy efficiency and response speed of tactile systems. This review systematically discusses the physical mechanisms of mainstream memristors, highlights recent progress in memristor-based neuromorphic computing for tactile sensing, and outlines key challenges and future directions for neuromorphic tactile perception systems.

Micro-scale light-emitting diodes (Micro-LEDs) are evolving from display devices to powerful biomedical tools owing to their miniaturization, low power consumption, flexibility and multi-wavelength capability. This review summarizes advances in Micro-LED biomedicine (2024−2026). It introduces core enabling technologies and classifies applications into implantable systems, wearable platforms and brain−computer interfaces, covering optogenetics, cardiac/tumor therapy, epidermal healthcare, visual prostheses and all-optical neural interfaces. Key challenges including biocompatibility, heat dissipation and packaging are discussed. Prospects such as closed-loop intelligent systems, degradable devices and clinical translation are proposed. This review highlights Micro-LEDs’ great potential for next-generation precision medicine.

Real-time physiological signal monitoring transforms health management from 'passive treatment' to 'active prevention' and from 'vague perception' to 'precise control'. Triboelectric pressure sensing technology exhibits inherent advantages including high sensitivity, diverse material selection, and superior dynamic performance. It is highly compatible with flexible substrates, thus demonstrating enormous application potential in the monitoring of human physiological signals as well as human−computer interaction. In this review, we present the types and the advantages and disadvantages of pressure sensors. In addition, the basic principles and preparation methods of triboelectric pressure sensors are introduced, and their research progress in the field of human signal detection is summarized, including their applications in pulse signal monitoring, sleep monitoring, and gait detection. Finally, the constraints on the practical application of triboelectric pressure sensors are discussed. This review is expected to provide readers with some general strategies and novel ideas for conducting in-depth research on sensors with better performance for physiological signal recognition.