Harnessing Biobased Materials in Photosynaptic Transistors with Multibit Data Storage and Panchromatic Photoresponses Extended to Near-Infrared Band

Owing to ever-increasing environmental impact, nature-inspired biomimetic electronics are key to unlock the potential of developing environmentally friendly brain-like computing and biomimetic artificial-intelligence systems. Thus far, the development of photosynaptic devices via green processing using biobased materials has become a major challenge, owing to restrictions in complex architecture, material design, and stimulation wavelength. This article reports on the first bioinspired phototransistor using biocomposites comprising semiconducting block copolymers, poly(3-hexylthiophene)-block-maltoheptaose, and bacteriochlorophyll (BCHL), which extend the photoresponse from visible to UV to near-infrared light, to exhibit fundamental sensing, computing, and memory functions. The superior ultrafast (50 ms) and multilevel (>9 bits) photoresponses of a single cell of the synaptic devices are attributed to hydrogen-bonding interaction (i) between the block copolymers to facilitate the self-assembled microstructure, and (ii) within the block copolymer and BCHL to homogeneously disperse the natural chromophore. Notably, a two-terminal flexible synaptic device comprising biocomposites and a biobased poly(ethylene furanoate) substrate with high mechanical endurance is demonstrated to exhibit synaptic functionality and environmentally benign properties without using a gate impetus and hazardous ingredients. Collectively, the photosynaptic transistor comprising a biocomposite successfully provides an effective guide for applications in artificial visual perception, sensing, and memory in neuromorphic computing and intelligent systems.