Fig. 2: Photonic non-volatility of the single-element neuromorphic devices.

a Schematic of the organic device. b Schematic diagrams of the mechanism processes. c Chemical structure of the organic semiconductors utilized in the device. d Photonic responses demonstrating memory characteristics of the device. Applied stimulation light: 455 nm, 100 mW cm⁻², and 100 s. e Photon-triggered STP and LTP of the device. Stimulation used 455 nm, 100 mW cm⁻² light pulses, 1 s in duration, at 0.1 Hz for STP and 0.5 Hz for LTP. f PPF index of the device relative to spike time interval (ΔT) with the same light condition (power density of 100 mW cm⁻² and duration of 1 s). g Photon-triggered LTP of the device with and without MPTS coating. h Characteristic photonic responses of the neuromorphic device. The device was initially stimulated with 10 light pulses (455 nm, 100 mW cm⁻², 1 s duration) at a frequency of 0.5 Hz. Subsequently, the power supply was interrupted for 40 to 80 s, as indicated by the pink-shaded region. i Memory retention time traces of devices with varying acceptor (PZ1) weight ratios. Each device was stimulated with 100 light pulses (power density of 100 mW cm⁻², 1 s duration) at a frequency of 0.5 Hz. j EPSC (blue line) and delay times (red line) of devices with different PZ1 weight ratios after stimulating with 100 light pulses (100 mW cm⁻², duration of 1 s and frequency of 0.5 Hz). k I-T response curves of the devices at acceptor (PZ1) weight of 50%.