Fully screen-printed paper-based ZnO synaptic transistor arrays for visual perception and neuromorphic computing

Large-area, paper-based ZnO synaptic transistor arrays for visual perception and neuromorphic computing have been fabricated for the first time entirely by screen printing. The channel ink was formulated by dispersing ZnO nanoparticles with a small amount of hydroxyl-rich ethyl cellulose in terpineol, which converted into a semiconducting film at a low temperature of 90 °C. The paper-based transistor arrays exhibited desirable electrical properties, large-area uniformity, environmental stability and biodegradable, making them particularly promising as disposable devices. The printed ZnO synaptic transistors demonstrated exceptional photoelectric synaptic behaviors, including paired-pulse facilitation and depression, high-pass and low-pass filtering, learning, forgetting, relearning, Morse code recognition, and short-term/long-term plasticity, all at a low energy consumption of about 3.7 pJ per synaptic event. Artificial visual learning and information storage capabilities were achieved owing to the persistent photoconductance effect of the printed ZnO films, achieving an accuracy of 91.4% in neuromorphic computing through optoelectronic co-modulation.