Retina‐Inspired Artificial Synapses with Ultraviolet to Near‐Infrared Broadband Responses for Energy‐Efficient Neuromorphic Visual Systems

Abstract

Neuromorphic visual system with image perception, memory, and preprocessing functions is expected to simulate basic features of the human retina. Organic optoelectronic synaptic transistors emulating biological synapses may be promising candidates for constructing neural morphological visual system. However, the sensing wavelength range of organic optoelectronic synaptic transistors usually limits their potential in artificial multispectral visual perception. Here, retina‐inspired optoelectronic synaptic transistors that present broadband responses covering ultraviolet, visible, and near‐infrared regions are demonstrated, which leverage the wide‐range photoresponsive charge trapping layer and the heterostructure formed between PbS quantum dots and organic semiconductor. Simplified neuromorphic visual arrays are developed to simulate comprehensive image perception, memory, and preprocessing functions. Benefitting from the flexibility of the charge trapping and organic semiconductor layers, a flexible neuromorphic visual array can be fabricated, having an ultralow power consumption of 0.55 fJ per event under a low operating voltage of −0.01 V. More significantly, an accelerating image preprocessing effect can be observed in a wide wavelength range even beyond the perception range of the human visual system, due to the gate‐adjustable synaptic plasticity. These devices are highly promising for implementing neuromorphic visual systems with broadband perception, increasing image processing efficiency, and promoting the development of artificial vision.

Stretchable and neuromorphic transistors for pain perception and sensitization emulation

“…Synapses are the basic units to carry out the transmission task, as they mediate the information transfer and integration through synaptic plasticity. 25,33,42–48 Synapses consist of three parts: the presynaptic membrane, the synaptic cleft, and the postsynaptic membrane. The presynaptic membrane releases certain neurotransmitters that diffuse through the synaptic gap to the postsynaptic membrane, causing excitatory or inhibitory potentials in the postganglionic neurons (Fig.…”

Energy-Efficient ReS2-Based Optoelectronic Synapse for 3D Object Reconstruction and Recognition

“…As the frequency increases, the gain gradually ascends, exhibiting an apparent high-pass characteristic. Based on this, the cutoff frequency (f c = 1.95 Hz) can be obtained by fitting the dependence of the gain on the frequency with an exponential high-pass filter function, 45 indicating that the synapse device may imitate the feature extraction of HVS. The flower image with only brightness information is regarded as the visual input, as shown in Figure 2f.…”

Optoelectronic Synaptic Transistors Based on Solution-Processable Organic Semiconductors and CsPbCl3 Quantum Dots for Visual Nociceptor Simulation and Neuromorphic Computing

“…The I DS of the OST is enhanced, resulting from the increment of the hole density in the PDPP4T channel. The increased I DS can remain for a long period because it is difficult for the trapped electrons in the partial CsPbCl 3 QDs embedded in the PMMA film to enter the PDPP4T channel and recombine with the holes in a short time. ,, After a negative V GS pulse, the bending of the energy bands reverses, which facilitates the release of the trapped electrons and promotes their injection into the PDPP4T channel. The injected electrons promptly recombine with the holes, bringing I DS back to its initial level.…”

“…The degree of injury may be relevant to the intensity and duration of the UV exposure. − Consequently, it is interesting to develop artificial electronics for simulating nociceptive receptors and realizing pain perception with UV irradiation. Inspired by the PNS, diverse synaptic devices have been proposed as promising artificial electronics to acquire human-like behaviors, including perceptual characteristics. ,− Optoelectronic synaptic devices that combine the functions of photodetectors and artificial synapses create a more compact structure than the one made up of those two types of devices, indicating a promising application in artificial sensory systems. ,− Recently, most reported devices have owned relatively wide wavelength responses in the spectral region from UV to visible (VIS)/near-infrared (NIR) or limited wavelength responses in VIS or NIR regions. ,,− It is still challenging to fabricate optoelectronic synaptic devices with excellent wavelength selectivity in the UV region without overlapping the VIS and NIR regions. To simulate and further prevent damage from UV irradiation to the visual sensory system, it is essential to enhance the perception selectivity of optoelectronic synaptic devices in UV irradiation.…”