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Developing multifunctional and diversified artificial neural systems to integrate multimodal plasticity, memory, and supervised learning functions is an important task toward the emulation of neuromorphic computation. Here, we present a bioinspired mechano-photonic artificial synapse with synergistic mechanical and optical plasticity. The artificial synapse is composed of an optoelectronic transistor based on graphene/MoS2 heterostructure and an integrated triboelectric nanogenerator. By controlling the charge transfer/exchange in the heterostructure with triboelectric potential, the optoelectronic synaptic behaviors can be readily modulated, including postsynaptic photocurrents, persistent photoconductivity, and photosensitivity. The photonic synaptic plasticity is elaborately investigated under the synergistic effect of mechanical displacement and the light pulses embodying different spatiotemporal information. Furthermore, artificial neural networks are simulated to demonstrate the improved image recognition accuracy up to 92% assisted with mechanical plasticization. The mechano-photonic artificial synapse is highly promising for implementing mixed-modal interaction, emulating complex biological nervous system, and promoting the development of interactive artificial intelligence.

With the arrival of the Internet of Things (IoTs) era, there is a growing requirement for systems with many sensor nodes in a variety of fields of applications. The demands for wireless, sustainable and independent operation are becoming more and more important for large‐scale sensor networks and systems. For these purposes, a self‐powered sensory system that can utilize the self‐harvested energy from its surroundings to drive the sensors and directly sense external stimuli has attracted great attention. The invention and rapid development of piezoelectric generators (PENGs), which take Maxwell's displacement current as the driving force, has been pushing forward research on self‐powered active mechanical sensors, electronic skins, and human‐robotic interaction. Here, this review starts with a brief introduction of piezoelectric materials, fabrication, and performance improvement. Then, the energy harvesters used for self‐power systems based on recent progress are reviewed. After that, PENGs applications toward recent self‐powered active sensors are divided into four aspects and highlighted, respectively. Moreover, some challenges and future directions for the self‐powered multifunctional sensors are put forward. It is believed that through the continuous investigations into PENG‐based self‐powered active sensors, they will soon be used in touch screens, electronic skins, health care, environmental monitoring, and intelligence systems.

Low-frequency dielectric polarization of single-walled carbon nanotubes (SWNTs) not only affects charge carrier transport in SWNT-based nanoelectronic devices but also determines their interaction with molecules, other nanomaterials, and external fields. Differential dielectric responses of metallic and semiconducting SWNTs are critical in electronic-type sorting of SWNTs. Here, we describe the measurement of low-frequency dielectric polarization of individual SWNTs without making electrical contacts to the nanotubes. Qualitative contrast is observed between metallic and semiconducting SWNTs due to drastically different longitudinal polarizabilities. This is developed into a facile assay for metallic and semiconducting contents in SWNT samples.

Fibrous energy−autonomy electronics are highly desired for wearable soft electronics, human−machine interfaces, and the Internet of Things. How to effectively integrate various functional energy fibers into them and realize versatile applications is an urgent need to be fulfilled. Here, a multifunctional coaxial energy fiber has been developed toward energy harvesting, energy storage, and energy utilization. The energy fiber is composed of an all fibershaped triboelectric nanogenerator (TENG), supercapacitor (SC), and pressure sensor in a coaxial geometry. The inner core is a fibrous SC by a green activation strategy for energy storage; the outer sheath is a fibrous TENG in single-electrode mode for energy harvesting, and the outer friction layer and inner layer (covered with Ag) constitute a selfpowered pressure sensor. The electrical performances of each energy component are systematically investigated. The fibrous SC shows a length specific capacitance density of 13.42 mF•cm −1 , good charging/discharging rate capability, and excellent cycling stability (∼96.6% retention). The fibrous TENG shows a maximum power of 2.5 μW to power an electronic watch and temperature sensor. The pressure sensor has a good enough sensitivity of 1.003 V•kPa −1 to readily monitor the real-time finger motions and work as a tactile interface. The demonstrated energy fibers have exhibited stable electrochemical and mechanical performances under mechanical deformation, which make them attractive for wearable electronics. The demonstrated soft and multifunctional coaxial energy fiber is also of great significance in a sustainable human−machine interactive system, intelligent robotic skin, security tactile switches, etc.

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