Fig. 4: Optoelectronic synapse characteristics.

a–d EPSC responses of the memristors integrated with various organic thin films: a, c DNH-F and b, d CH-P. Light pulse conditions are illustrated in top figures. Read voltage is 0.05 V. a, b Depending on the amplitude of the light pulse (pulse widths are fixed): UV pulse (365 nm and 0.5 s width) and B-light pulse (450 nm and 1 s width) are used for the memristor with DNH-F and that with CH-P. c, d Depending on the width of the light pulse (pulse amplitudes are fixed): UV pulse (365 nm and 3 mW cm⁻²) and B-light pulse (450 nm and 5 mW cm⁻²) are used for the memristor with DNH-F and that with CH-P. e, f PPF index as a function of interval between two consecutive pulses (Δt). Read voltage is 0.05 V. e Amplitude and width of UV pulse (365 nm) for the memristor with DNH-F are 3 mW cm⁻² and 0.5 s. f Those of B-light pulse (450 nm) for the memristor with CH-P are 5 mW cm⁻² and 1 s. Bottom inset figures of (e, f) are about PPF behaviors by a pair of presynaptic pulses for 0.5 s (DNH-F) and 1 s (CH-P) interval cases. Top inset figures of (e, f) illustrate the applied light pulse conditions.