Optoelectronic synaptic devices, which combine the functions of photosensitivity and information processing, are essential for the development of artificial visual perception systems. Nevertheless, improving the paired pulse facilitation (PPF) index of optoelectronic synaptic devices, which is an urgent problem in the construction of high‐precision artificial visual perception systems, has received less attention so far. Herein, a light‐stimulated synaptic transistor (LSST) device with an ultra‐high PPF index (≈196%) is presented by introducing an ultra‐thin carrier regulator layer hexagonal boron nitride (h‐BN) into a classic graphene‐based hybrid transistor frame (graphene/CsPbBr3 quantum dots). Crucially, analysis of the rate‐limiting effect of h‐BN on photogenerated carriers reveals the mechanism behind the LSST ultra‐high PPF index. Furthermore, a two‐layer artificial neural network connected by LSST devices demonstrate ≈91.5% recognition accuracy of handwritten digits. This work provides an effective method for constructing artificial visual perception systems using a hybrid transistor frame in the future.
Light‐Stimulated Synaptic Transistors
Optoelectronic synaptic devices with a high paired pulse facilitation index are essential for constructing high‐precision artificial visual perception systems. In article number 2113053, Jun Wang and co‐workers develop a light‐stimulated synaptic transistor with an ultra‐high PPF index (≈196%) by introducing hexagonal boron nitride into a classic graphene‐based hybrid transistor framework, which provides an effective method for constructing artificial visual perception systems in the future.
Mimicking the real-time sensing and processing capabilities of human retina opens up a promising pathway for achieving vision chips with high-efficient image processing. The development of retina-inspired vision chip also requires hardware with high sensitivity, fast image capture, and the ability to sense under various lighting conditions. Herein, a high-performance phototransistor based on graphene/organic heterojunction is demonstrated with a superior responsivity (2.86 × 10 6 A W −1 ), an outstanding respond speed (rise time/fall time is 20 µs/8.4 ms), and a remarkable detectivity (1.47 × 10 14 Jones) at 650 nm. The phototransistor combines weak-light detection capability (minimum detectable light intensity down to 2.8 nW cm −2 ) with gate-tunable bi-directional photoresponse capable of simultaneously sensing and processing visual images for light intensities ranging over six orders magnitude (10-10 7 nW cm −2 ). Moreover, the phototransistor also exhibits an intriguing feature undiscovered in other retina-inspired devices, namely that it can real-time monitor the human pulse signal and heart rate by using photoplethysmography technology, and the measured heart rate error is only 0.87% compared with a commercially available sensor. This study paves the way for the development of low-light and bio-signal sensitive artificial retinas in the future.
With the emerge of bismuth-based oxychalcogenide materials, Bi2O2Se shows superiority in photo-detection due to its favorable mobility and air-stability. Nevertheless, the photo-detection performance is limited by its low bandgap and...
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