Fig. 4: Synaptic characteristics and switching mechanism of the fiber-shaped ionic transistor.
From: Integrated opposite charge grafting induced ionic-junction fiber
a Schematic illustration of a natural biological synapse. For the function of the synapse, the advent of an action potential releases neurotransmitters that aid ion channels for signal transmission from the presynaptic pulse to the postsynaptic response. b Schematic illustration of the three-terminal synaptic IBJT. The emitter and collector are used as the postsynaptic output terminals, while a presynaptic voltage applied on the base will trigger a postsynaptic current (IPSC) in the ionic-junction fiber. The right schematic presents the cross-section of the synaptic IBJT device. c A negative presynaptic potential (Vpresynaptic) drove Cl− into the postsynaptic electrode while Na+ accumulated near the heterojunction in the device due to the application of the postsynaptic voltage (Vpostsynaptic) during an open-read operation. d Schematic explaining the decoupling of the read and write operations of synaptic IBJT. e Paired pulse facilitation (PPF). Two equally sized 500 ms pulses are applied shortly after each other to facilitate an increase in the current of the second pulse depending on the time delay between the two pulses. The two pulses did not permanently change the conductivity of the device as the current reaches the initial baseline after 23 s. f When multiple presynaptic voltages are applied, the PPF (ID) can be manifested by the ratio between the IPSC measured immediately after the first pulse current (ID1) and the last pulse current (IDn). g IPSC is triggered by multiple presynaptic pulses with a consistent duration time (180 ms) and different amplitudes (−0.5, −1.0, −1.5, −2.0, and −3.0 V). Source data are provided as a Source Data file.
