Organic molecular crystal-based photosynaptic devices for an artificial visual-perception system

Abstract

Recreating the visual-perception properties using organic electronic devices is highly desired for visual prosthetics and artificial intelligence. Although the integration of organic light-sensing components with synaptic devices can realize the recognition and memory functions for perceived images, complicated problems in device integration for practical applications are generally encountered. Here we demonstrate a new type of organic photosynaptic device based on organic molecular crystals, which can provide optical-sensing and synaptic functions together in one device by means of a unique photon-induced charge transfer effect. This device successfully emulates the working principles of human visual perception in terms of short-term plasticity, long-term potentiation, and spike-timing-dependent plasticity. Moreover, a proof-of-concept artificial image-perception system is demonstrated by integrating the photosynapses on a flexible substrate. The new devices using organic semiconductors may open up innovative application areas, such as artificially intelligent electronic and perception systems, and facilitate the integration of such devices into nextgeneration flexible and stretchable electronics.

Evolution of Bio‐Inspired Artificial Synapses: Materials, Structures, and Mechanisms

“…Light‐, gas‐, and pressure‐sensitive ASs are developed recently either in a single device or in an integrated system with separated sensors. [ 119–126 ]…”

“…Light-, gas-, and pressure-sensitive ASs are developed recently either in a single device or in an integrated system with separated sensors. [119][120][121][122][123][124][125][126] A flexible conformable AS was demonstrated as a human olfactory system to simulate human organ-damage memory behavior toward toxic NO 2 gas (Figure 10a). [119] This gas-sensitive FET-based AS was fabricated using poly[4-(4,4-dihexadecyl-4H-cyclopenta-[1,2-b:5,4-b0]dithiophen-2-yl)-alt- [1,2,5] thiadiazolo [3,4-c]pyridine] (PCDTPT) thin film on a freestanding PVA substrate.…”

Recent Progress of Optoelectronic and All‐Optical Neuromorphic Devices: A Comprehensive Review of Device Structures, Materials, and Applications

“…Deng et al proposed a three‐terminal planar structure device using 2,8‐difluoro‐5,11‐bis(triethylsilylethynyl) anthradithiophene (diF‐TES‐ADT) crystal arrays serving as a photoactive layer. [ 81 ] In dark condition, the device showed typical p‐type transistor characteristics. Under light illumination ( λ = 757 nm and power intensity of 10 μW cm −2 ), EHPs are generated in the active layer.…”

Retina-Inspired Organic Heterojunction-Based Optoelectronic Synapses for Artificial Visual Systems

“…Nearly 80% of the obtained information, among these external stimuli, is detected through human visual systems [ 2 , 3 ]. Hence, retinas are supposed to be one of the most significant sensory organs in human bodies, which have stimulated the emergence of artificial vision by bioinspired electronics [ 4 – 7 ]. Additionally, towards the future development of humanoid soft robots and artificial intelligence systems, there is a tremendous demand to design advanced photoelectric detection devices capable of being operated under various ambient conditions to strengthen and ultimately substitute for human visual systems in the field of industry, science, and military [ 8 – 11 ].…”