Fig. 2. Mimicking STP using an OECT artificial synapse.

a Patterns of pulsed gate voltage with different parameters; V_p: voltage amplitude, $△t$: pulsed voltage interval time, t_p: pulsed voltage duration, T_p: pulsed voltage period. b Channel current modulation induced by 10 consecutive gate voltage pulses in the P-80% PTHF-based OECT. c Transient response of the PEDOT:Tos/PTHF-based OECT with different PTHF blend ratio. All the dashed lines are exponential decay fitting curves. The rise-time of the current pulse when the gate voltage was applied is defined as response time, while the decay-time of the current pulse after the gate voltage was removed is defined as ion relaxation time. The response time of devices with different PTHF blend ratio are ${\tau }_{\mathrm{res}\_0}=0.143\mathrm{ms},{\tau }_{\mathrm{res}\_20}=0.269\mathrm{ms},{\tau }_{\mathrm{res}\_50}=0.387\mathrm{ms},{\tau }_{\mathrm{res}\_80}=2.104\mathrm{ms},{\tau }_{\mathrm{res}\_90}=7.113\mathrm{ms}$. The ion relaxation time of devices with different PTHF blend ratio are ${\tau }_{\mathrm{rel}\_0}=0.288\mathrm{ms},{\tau }_{\mathrm{rel}\_20}=0.241\mathrm{ms},{\tau }_{\mathrm{rel}\_50}=0.692\mathrm{ms},{\tau }_{\mathrm{rel}\_80}=2.824\mathrm{ms},{\tau }_{\mathrm{rel}\_90}=5.659\mathrm{ms}$. d, e Paired-pulse facilitation (PPF) and post-tetanic potentiation (PTP) indexes as a function of OECT channel composition and interval time of gate pulses, under t_p of 1 ms. Gray dashed lines are the fitting curves.