Zero-power optoelectronic synapses, defined as optoelectronic synaptic devices operating without external electrical bias, are emerging as core components for energy-efficient intelligent wearable neuromorphic platforms. Wearable neuromorphic systems require continuous, autonomous operation under strict constraints on power consumption, mechanical compliance, and thermal safety, making conventional electrically biased synaptic devices impractical for long-term body-interfaced use. By harvesting light to drive synaptic modulation without external bias, these devices integrate sensing, learning, memory, and processing within a single self-sustained element. This light-driven operation is therefore particularly well suited for wearable platforms, where energy availability is limited and frequent recharging or battery replacement is undesirable. This review summarizes recent progress in zero-power optoelectronic synapses based on three representative mechanisms: Schottky junctions, heterojunctions, and photothermoelectric effect. Despite notable progress, several fundamental challenges continue to limit practical deployment. These include limited light utilization, insufficient bidirectional weight modulation, instability and variability, mechanical incompatibility, and lack of system-level integration, which remain major hurdles. These limitations hinder the reliable operation, scalability, and long-term applicability of zero-power optoelectronic synapses in realistic wearable neuromorphic platforms. Finally, this review proposes technological strategies for addressing these challenges. We further outline how these advances could enable practical, scalable, and mechanically compliant synaptic platforms for future energy-autonomous, body-interfaced neuromorphic systems capable of continuous perception and intelligent processing.

Bidirectional optical synaptic plasticity is essential for hardware-based neuromorphic computing because it provides functional versatility beyond unidirectional operation. However, most reported organic optoelectronic synaptic devices remain constrained by unidirectional modulation, complex hybrid configurations, and limited mechanical adaptability, hindering their integration into electronic platforms. Here, we introduce an all-soft organic bipolar optoelectronic synapse that achieves bidirectional weight modulation through spatially selective optical stimuli. The device consists of two serially connected all-soft organic photoconductors and exploits persistent photoconductivity to emulate diverse synaptic behaviors while maintaining stable, multilevel, reconfigurable states under 50% tensile strain. We demonstrate a hardware-level vector-matrix multiplication on an all-soft, optically driven synaptic array, providing direct evidence of parallel analog computation on a fully deformable platform. By combining bidirectional optical plasticity, soft mechanical integration, and hardware-level vector-matrix multiplication, this all-soft organic synaptic platform provides a route toward optically programmable neuromorphic hardware for wearable and skin-conformal AI systems.

Human-machine interfaces demand soft bioelectronic systems capable of acquiring high-fidelity electrophysiological signals while maintaining mechanical compliance comparable to human skin. Here, we report a stretchable and conductive electrode array based on a PEDOT:PSS composite modified with Poloxamer and polar solvents. The synergistic doping strategy enhanced mechanical compliance, reduced impedance, and improved conformability, enabling stable acquisition of diverse electrophysiological biosignals. To realize a practical bioelectronic system, the electrode array was integrated with a custom-designed, low-power biointerface circuit capable of multichannel amplification, filtering, and digitization. The integrated platform enabled real-time classification of hand gestures from 20-channel electromyography recordings with high accuracy. Furthermore, we demonstrate its application as a human-machine interface by enabling calculator control as an augmentative and alternative communication tool. This work lays the technological foundation for next-generation stretchable bioelectronic interfaces, bridging human intent and machine intelligence through seamless, reliable interaction.

Irreproducible wrinkling, characterized by randomly arranged ridges or creases on material surfaces, has significant potential for application in entity identification and anti-counterfeiting. However, active research in this field is hindered because the existing wrinkling methods face challenges in realizing discernible patterns and potential applications of submillimeter-scale wavelength wrinkles are yet to be identified. Herein, we propose a strategy to create unique and irreproducible styrene-ethylene-butylene-styrene (SEBS) wrinkles using "spin evaporation", a technique that rapidly removes the solvent by spinning. We demonstrate the realization of SEBS wrinkles with wavelengths of hundreds of micrometers with high randomness, irreproducibility, and resistance to external stimuli. Importantly, to demonstrate the potential application of the wrinkle, we suggest and fabricate a human-finger-like fully soft identifiable artificial finger pad electronics and integrate it with a soft bimodal sensing system. The artificial finger pad mimics human finger pad features such as identification, object recognition, and effective grasping. Further integration of this pad into soft robots, cephalopods, and prosthetic skin offers insightful potential for the proposed wrinkling method in various fields.

Complementary integrated circuits in an elastic format are essential for systems toward emerging applications in wearable health monitors, soft robotics, and implantable medical devices. However, their development is very nascent, largely owing to the imbalance of p- and n-type elastic transistors. Here, we report fully stretchable complementary integrated electronics combining elastic n-type transistors based on metallic carbon nanotube (CNT)-oped poly{[N,N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)} with p-type transistors using semiconducting CNT networks. The layered elastomer-semiconductor-elastomer architecture provides both type transistors with stable, well-matched electrical characteristics up to 50% strain. Using these components, we demonstrate stretchable digital logic gates-including inverters, NAND, and NOR-which retain function under large strain. As a system-level demonstration, a complementary inverter active matrix integrated with a single-electrode triboelectric nanogenerator array realizes a stretchable tactile sensing skin. The stretchable complementary integrated electronics demonstrated here hold promise in many fields, particularly these require seamless integration with dynamic living systems.

Organic semiconductors (OSCs) have emerged as essential building blocks for next-generation electronics due to their intrinsic mechanical softness, solution processability, and compatibility with flexible, stretchable, and wearable platforms. However, despite their expanding applications, the environmental and economic implications of OSCs throughout their entire lifecycle, including energy- and solvent-intensive synthesis as well as end-of-life disposal, remain insufficiently addressed. Indeed, the environmental footprint of OSCs is intensified not only by their chemically robust backbones, which resist natural degradation and complicate waste management, but also by synthesis processes that generate large volumes of toxic solvent-based waste. In this Perspective, we first highlight the growing importance of OSC recycling, from both environmental and economic standpoints, as it relates to current organic electronics. We then review recent advances in OSC recycling, encompassing both molecular-level strategies based on chemical depolymerization/repolymerization and materials-level approaches involving selective extraction and reuse. Finally, we discuss the key remaining challenges and propose a critical outlook that emphasizes not only the technical and scientific advancement of OSC recycling technologies but also the adoption of a recyclability-by-design approach. Together, these efforts are essential to enable sustainable organic electronic systems.

We report all-soft vertical organic photodetectors composed of only soft components. Chemically and physically enhanced interfacial adhesion between layers enables robust operation under mechanical deformation. Their excellent light-sensing capability and deformable features, combined with powerless operation, promise significant advancements in optoelectronic applications.

Soft electronics have achieved significant development, attracting substantial interest due to their promising potential as a dominant form of future electronics. In this rapidly evolving field, the fully soft Schottky diode plays a critical role as a fundamental building block for electronic circuitry systems. These systems, constructed entirely from soft materials, can tolerate various mechanical deformations when interfaced with human skin, making them ideal for use in health monitoring systems and interactive human-machine interfaces. In this study, we introduce a Schottky diode fabricated entirely from soft materials using a facile solution process, further enabling all-printing fabrication systems. Utilizing the mechanical softness of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate-based soft electrode, poly(3-hexylthiophene) nanofibril composite soft semiconductor, and liquid metal, we successfully fabricated a fully soft Schottky diode. This diode exhibits exceptional electrical characteristics even under various mechanical deformations, showcasing the high durability of the device. We have further developed fully soft rectifiers and logic gates, highlighting the versatility of our study. By incorporating these devices with a piezoelectric nanogenerator in a skin-interfaced energy harvesting system, they exhibit sufficient capability for rectification, ensuring a stable power supply as part of a power supply management system. This approach offers substantial potential for future skin-interfaced electronics, paving the way for advanced wearable technology.

Flexible organic electronics can be used to create wearable devices but the synthesis of organic electronic materials typically involves hazardous solvents, creates toxic by-products and has various other environmental and economic costs. Being able to recycle organic electronic materials and devices in an eco-friendly and economical manner is thus key for their application in sustainable wearable electronics. Here we report organic flexible electronic devices with closed-loop recycling of each component. We develop approaches to recapture and reuse organic conductors, semiconductors and gate dielectrics, and evaluate the reliability of the recycled materials. Our fabrication and recycling processes also use only eco-friendly solvents (water, anisole and acetone). We illustrate the capabilities of the approach with various recyclable organic flexible electronic devices, including electrophysiological sensing electrodes, keypads, heaters/temperature sensors, electrochemical transistors and inverters. We also develop a sustainable device cycle by reconstructing various organic flexible electronics, which are fabricated using recycled materials from different functional devices without further replenishment. Processes to recapture and reuse organic electronic materials—including conductors, semiconductors and dielectrics—using non-toxic solvents allow flexible, wearable electronic devices to be recycled sustainably.

Silver nanowires-embedded polydimethylsiloxane (AgNWs/PDMS) electrodes are promising components for various soft electronics, but face energy mismatch with organic semiconductors. Attempts at galvanic replacement, involving spontaneous gold (Au) formation on the electrodes, often result in non-uniform and particulate Au coatings, compromising device performance and stability. In this study, we introduce a novel approach for achieving a uniform and complete Au coating on AgNWs/PDMS electrodes by adding NaCl to the Au complex solution. This addition slows down the galvanic replacement process and prevents precipitation, enabling a uniform and complete Au coating on the AgNWs surface. Such coating significantly reduces contact resistance (RC), thereby enhancing the electrical characteristics of p-type organic transistors. Furthermore, the development of high-performance, fully soft organic transistors was achieved incorporating an organic semiconductor-elastomer blend. Additionally, reliable, mechanically stable soft glucose sensor was developed, taking advantage of the complete Au coating, which protects against oxidation during the glucose sensing process.

Tween 80, an eco-friendly surfactant, enables the creation of conductive composites and dry-adhesive films for skin-friendly strain sensors that adhere directly. This wearable technology is vital for smart health systems and human–machine interfaces.

Organic semiconductors employed in single crystalline form have several advantages over polycrystalline films, such as higher charge carrier mobility and better environmental stability. Herein, we report the fabrication and characterization of a solution-processed microsized single-crystalline organic wire of n-type N,N'-dipentyl-3,4,9,10-perylene tetracarboxylic diimide (PTCDI-C5). The crystal was applied as an active layer in polymer-gated organic field-effect transistors (OFETs) and organic complementary inverter circuits. The single crystaiiline nature of PTCDI-C5 wires were characterized using two-dimensional grazing incidence wide-angle X-ray diffraction (2D-GIXD) and polarized optical microscopy. OFETs with the PTCDI-C5 crystals exhibited high n-type performance and air stability under ambient conditions. To investigate the electrical properties of the single-crystalline PTCDI-C5 wire more precisely, OFETs with only one PTCDI-C5 microwire in the channel were fabricated, and clear n-type characteristics with satisfactory saturation behavior were observed. The device with only one crystal wire exhibited characteristics with significantly lower variation compared to the multicrystal devices, which shows that the density of crystal wires is a critical factor in precisely investigating device performance. The devices exhibited a reversible threshold voltage shift under vacuum and oxygen conditions, without changing the charge carrier mobility. Light-sensitive characteristics were also observed. Additionally, this solution-processed, highly crystalline organic semiconductor can be used in high-performance organic electronic circuits as well as in gas or light sensors.

Elastic integrated electronics are of potential use in a range of emerging applications, particularly those that require devices that can form an interface with soft biological tissue. The development of such devices has typically focused on the creation of stretchy p-type semiconductors, and the lack of suitable stretchy n-type semiconductors limits the potential of stretchable integrated systems. Here we show that a brittle n-type organic semiconductor can be made mechanically stretchable by integrating into a stack with an elastomer–semiconductor–elastomer architecture. The structure suppresses the formation and propagation of microcracks and can be stretched by up to 50% with negligible loss of performance. It also improves the long-term stability of the semiconductor in an ambient environment. We use the n-type elastomer–semiconductor–elastomer stack, together with other stretchy electronic materials, to build elastic transistors, digital logic gates, complementary electronics, p–n photodetectors and an active matrix multiplexed deformable imager.

Here, we propose fully soft OECTs with all soft components, including a PEDOT:PSS-based soft channel, which show substantial mechanical/electrical properties. In addition, the further demonstrated skin-mountable amplifier implies the strong potential of this work to be an innovative development in wearable electronics.

Abstract With growing interest and effort in developing organic electronics for future technologies such as wearable electronics, organic e-wastes generated during synthesis and disposal are becoming an inevitable environmental issue. Organic e-wastes possess unforeseeable potential genotoxicity and cytotoxicity in nature and humans, but efforts to reduce e-wastes have primarily focused on recapturing metallic materials. Here, we report a recyclable organic flexible (ROF) electronic device enabled by closed-loop recycling of entire materials recapturing and reusing through selective dissolution and spin-coating-free fabrication. The ROF electrode and electronics show reliable electrical properties under mechanical bending and after five times recycling. Moreover, ROF transistors and logic gates based on organic semiconductors and dielectrics were fabricated, and recycled devices show no considerable degradation. Finally, we achieved the sustainable devices cycle by reconstructing various ROF electronics using only recycled materials from different functional devices. The ROF electronics in this work provide a promising strategy for a sustainable future wearable electronic system.

The ideal epicardial bioelectronic patch should possess a cardiac tissue-like mechanical softness and deformability, and capability of spatiotemporal mapping of electrical and physical parameters. However, existing patches constructed from rigid materials with structurally engineered mechanical stretchability still form a hard-soft interface with the epicardium, which can strain cardiac tissue and does not allow for deformation with a beating heart. Alternatively, patches made from intrinsically soft materials lack spatiotemporal mapping or sensing capabilities. Here, we report the first epicardial bioelectronic patch that is made from materials that match the mechanical softness of heart tissue and is capable of multiplexed ECG mapping, strain and temperature sensing, electrical pacing, thermal ablation, and energy harvesting functions.

Neurologic function implemented soft organic electronic skin holds promise for wide range of applications, such as skin prosthetics, neurorobot, bioelectronics, human-robotic interaction (HRI), etc. Here, we report the development of a fully rubbery synaptic transistor which consists of all-organic materials, which shows unique synaptic characteristics existing in biological synapses. These synaptic characteristics retained even under mechanical stretch by 30%. We further developed a neurological electronic skin in a fully rubbery format based on two mechanoreceptors (for synaptic potentiation or depression) of pressure-sensitive rubber and an all-organic synaptic transistor. By converting tactile signals into Morse Code, potentiation and depression of excitatory postsynaptic current (EPSC) signals allow the neurological electronic skin on a human forearm to communicate with a robotic hand. The collective studies on the materials, devices, and their characteristics revealed the fundamental aspects and applicability of the all-organic synaptic transistor and the neurological electronic skin.

Curvy imagers that can adjust their shape are of use in imaging applications that require low optical aberration and tunable focusing power. Existing curvy imagers are either flexible but not compatible with tunable focal surfaces, or stretchable but with low resolution and pixel fill factors. Here, we show that curvy and shape-adaptive imagers with high pixel fill factors can be created by transferring an array of ultrathin silicon optoelectronic pixels with a kirigami design onto curvy surfaces using conformal additive stamp printing. An imager with a 32 × 32-pixel array exhibits a fill factor, before stretching, of 78% and can maintain its electrical performance under 30% biaxial strain. We also develop an adaptive imager that can achieve focused views of objects at different distances by combining a concave-shaped imager printed on a magnetic rubber composite with a tunable lens. Adaptive optical focus is achieved by tuning both the focal length of the lens and the curvature of the imager, allowing far and near objects to be imaged with low aberration.

An epicardial bioelectronic patch is an important device for investigating and treating heart diseases. The ideal device should possess cardiac-tissue-like mechanical softness and deformability, and be able to perform spatiotemporal mapping of cardiac conduction characteristics and other physical parameters. However, existing patches constructed from rigid materials with structurally engineered mechanical stretchability still have a hard–soft interface with the epicardium, which can strain cardiac tissue and does not allow for deformation with a beating heart. Alternatively, patches made from intrinsically soft materials lack spatiotemporal mapping or sensing capabilities. Here, we report an epicardial bioelectronic patch that is made from materials matching the mechanical softness of heart tissue and can perform spatiotemporal mapping of electrophysiological activity, as well as strain and temperature sensing. Its capabilities are illustrated on a beating porcine heart. We also show that the patch can provide therapeutic capabilities (electrical pacing and thermal ablation), and that a rubbery mechanoelectrical transducer can harvest energy from heart beats, potentially providing a power source for epicardial devices.

In article number 1902417, Cunjiang Yu and co-workers review the recent advances in rubbery electronics. Rubbery electronics is a class of electronics that is comprised of intrinsically stretchable elastomeric electronic materials. This cover illustrates a piece of rubbery electronics and circuits in the format of a glove.