Self‐Powered Embedded‐Sensory Adjustment for Flow Batteries

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Graphene has attracted considerable interest for next‐generation electronics. However, the absence of natural bandgap has limited the current on/off ratio of graphene‐based transistors. Vertical integration of 2D heterostructures offers a promising approach to address this challenge, enabling high‐current‐density vertical field‐effect transistor (VFET) with large on/off ratio. Here, a triboelectric potential‐powered VFET with a vertical stacked graphene/MoS2 heterostructure and a sliding‐mode triboelectric nanogenerator (TENG) coupled with gate dielectrics are proposed. The tribotronic VFET has an ultrashort channel length in vertical direction, exhibiting excellent current driving capability with an ultrahigh on‐state current density of 950 A cm−2 and a good current on/off ratio of 630. It also demonstrates reconfigurable diode behavior with a rectification ratio over 102. Temperature‐dependent studies are applied to tribotronic devices for the first time, indicating an effective modulation on the Schottky barrier height of 150 meV by the triboelectric potential. A green LED pixel is driven by the tribotronic VFET as a demonstration to work as a tactile interactive light‐emitting device. The demonstrated tribotronic vertical device offers a promising strategy for integrating various 2D layered materials with TENG in vertical direction, enabling 3D integration of low‐power and interactive devices for next‐generation electronics.

Tribotronic Vertical Field‐Effect Transistor Based on van der Waals Heterostructures

Wang,

Lin,

Gao

et al. 2024

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A Self‐Powered Dual Ratchet Angle Sensing System for Digital Twins and Smart Healthcare

Liu,

Gu,

Yang

et al. 2024

In the swiftly progressing landscape of wearable electronics and the Internet of Things (IoTs), there is a burgeoning demand for devices that are lightweight, cost‐effective, and self‐powered. In this study, a self‐powered bidirectional knee joint motion monitoring system is introduced, leveraging a dual ratchet sensing (DRS) system fabricated using 3D printing technology. This approach offers substantial economic and portability benefits. The DRS system is engineered to harness the negative work generated from knee joint movements to power commercial electronic devices, obviating the need for additional metabolic energy from the human body. By synergizing the DRS with virtual reality technology, it becomes feasible to monitor knee joint movements in real‐time with remarkable accuracy, presenting a novel avenue for the integration of digital twin technology. Through the amalgamation of convolutional neural network machine learning algorithms with Bayesian optimization techniques, the DRS system can discern up to 97% of knee joint movements, paving the way for innovative applications in smart rehabilitation and healthcare.

Flexible Pressure Sensor Arrays with High Sensitivity and High Density Based on Spinous Microstructures for Carved Patterns Recognition

Zhao,

Li,

et al. 2024

Owing to the superior stimulus perception, tactile function of skin is always the desire of flexible pressure sensor array (FPSA). However, achieving sensor arrays with high sensitivity and high resolution for tactile recognition like skin still remains a challenge. In this paper, an FPSA with high sensitivity (10.50 kPa−1), high density (1134.63 cm−2), and sufficient sensing units (4096 units) is developed, which is one of the best results up to now. The spinous microstructures, transferring from the abrasive papers, endow the sensor array with high sensitivity. Additionally, the high density array with adequate sensing units contributes to achieving high spatial resolution for identifying various surface features. This high‐performance FPSA can obtain detailed pressure distribution for complex carved patterns. With the assistance of machine learning, the FPSA can realize precise tactile recognition, 98.48% accuracy for 12 types of mahjong tiles, indicating a promising potential in an intelligent recognition system. It is worth noting that the relationship between surface microstructures and consistency is systematically investigated for the first time, which offers valuable insights for the preparation of high‐performance sensor arrays.