Photoresponsive dual-mode memory transistor for optoelectronic computing: charge storage and synaptic signal processing

Abstract

This study presents dual-mode memory transistor that accommodates memory and synaptic operations utilizing photoinduced charge trapping at the interface between poly(1,4-butanediol diacrylate) (pBDDA) and Parylene dielectric layer. Memory characteristics were implemented based on the photoresponsivity of dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT), enabling instantaneous electron storage under combined optical and electrical inputs, with retention times up to 10,000 s. Meanwhile, synaptic characteristics were induced by gradual charge trapping via optical pulse stimulation. Synaptic plasticity was confirmed via the potentiation–depression curve, emulating key features of biological nervous system, namely short-term memory (STM) and long-term memory (LTM). Furthermore, the fingerprint recognition tasks highlighted identification and authentication abilities by incorporating our synaptic function into an artificial neural network (ANN). The dual-mode memory transistor, fabricated on a business card, showed excellent compatibility with flexible optoelectronics, maintaining stable memory and synaptic performance over 500 bending cycles with minimal changes in memory window, memory ratio, and potentiation–depression behavior.