Fig. 4: Synaptic plasticity induced by optical stimulation.
a Schematic diagram of an optically modulated ZnO synaptic TFT. b Optical bandgap of printed ZnO film. c EPSC responds to 254, 365, 405 nm light at fixed intensities of 0.15, 0.2, and 0.3 mW/cm2, respectively. d EPSC triggered by 365 nm light with intensity increasing from 0.12 to 0.57 mW/cm2 over a duration of 0.2 s. e EPSC triggered by 365 nm light with durations ranging from 0.2 to 1.0 s at a constant intensity of 0.18 mW/cm2. f Relationship between EPSC, 365 nm light intensity, and duration. g The PPF index as a function of optical pulse interval (Δt) with the 365 nm light intensity of 0.23 mW/cm2 and the pulse width of 0.5 s (Inset is the EPSC response with an interval of 0.2 s between two optical pulses). h The learning, forgetting, and relearning process with 365 nm light intensity of 0.23 mW/cm2 and pulse width and interval of 0.2 s, respectively. i Optical responses to the Morse codes of the letter H, E, L, P.
