Fig. 1 Device processing for GEL/C-CS gated ITO neuromorphic transistor and characterization of GEL/C-CS composite electrolyte film (a) GEL/C-CS composite hydrogel at room temperature with inset showing molecular structures of GEL and C-CS; (b) Schematic diagram of fabricating ITO neuromorphic transistors with insets showing SEM images for cross-sectional and surface morphologies of the electrolyte film; (c) Schematic diagram of the mechanism of electric-double-layer formation; (d) Impedance spectroscopy data of the electrolyte film

Fig. 2 Electrical performances for GEL/C-CS gated ITO neuromorphic transistor at different relative humidities (a) Transfer curves; (b) Electric double layer capacitors (CEDL) for GEL/C-CS based electrolyte; (c) Carrier mobility (μ); (d) Subthreshold swing (SS); Colorful figures are available on website

Fig. 3 Synaptic responses of ITO neuromorphic transistor (a) EPSC responses triggered by a presynaptic spike (1 V, 10 ms) at relative humidity of 40%; (b) Peak EPSC value at different humidities; (c) EPSC responses triggered by two successive presynaptic spikes (1 V, 10 ms) at humidities of 40% and 80%; (d) Δt dependent PPF indexes at humidities of 40% and 80%

Fig. 4 Bionic quantitative processing of finger tactile to object recognition (a) Cross sectional sketch of skin tissue for unfolded fingers when touching objects; (b) EPSC triggered by pre-synaptic spike train at humidities of 40% and 80% with inset showing the definition of An; (c) $\Delta {{W}_{n}}$ as a function of n; (d, e) Degrees of recognition (R) at humidities of (d) 40% and (e) 80%, respectively

Fig. 5 MNIST pattern recognition (a, b) Synaptic weights updating obtained at humidities of (a) 40% and (b) 80%, respectively; (c) Schematic diagram of the two-layer MLP simulator; (d) Recognition accuracies at humidities of 40% and 80%; Colorful figures are available on website

Fig. S1 AFM surface morphology of GEL/C-CS electrolyte film

Fig. S2 Fig. S2 Electrical performances for GEL/C-CS gated ITO neuromorphic transistor at different relative humidities (a) Output curves; (b) On/off ratio; (c) Hysteresis

Fig. S3 Fig. S3 Modulation of EPSC responses for ITO neuromorphic transistor (a) EPSC responses under different spike amplitude with spike duration time fixed at 10 ms; (b) EPSC responses under different spike duration time with spike amplitude fixed at 1 V

Fig. S4 Schematic diagram of the spike trains for synaptic weight updating