In this talk, we will first demonstrate the working principle of the electrolyte-gated transistor with oxygen ions. We investigated the electrolyte gating induced phase transformation between SrCoO2.5 and SrCoO3−δ, combining in situ X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), electron energy-loss spectra (EELS), X-ray absorption spectra (XAS). The change in conductance amongst the two phases ( SrCoO2.5 ?  SrCoO3−δ), along with their temperature dependences, confirms that  SrCoO3−δ is a good metal while SrCoO2.5 is insulators.

And then, we realized the electrolyte-gated transistor to emulate the functions of a biological synapse. The emulation of synapses is important to realize efficient artificial-neuromorphic computers. Based on controlling the channel conductance via the insertion and extraction of O2− ions through electrolyte gating, we realized the nonvolatile multilevel memory states, and emulated important synaptic functions such as the synaptic long-term potentiation (LTP), long-term depression (LTD), synaptic spike-timing-dependent plasticity (STDP), and spiking logic operations. These results provide an alternative avenue for future neuromorphic devices via electrolyte-gated transistors with oxygen ions.

[1] Advanced Functional Materials, 29, 1902702 (2019).

[2] Advanced Materials, 30, 1801548 (2018).