Litfsi salt

ITO-coated glass substrates were sequentially cleaned with deionized water, acetone, and isopropyl alcohol. On the cleaned ITO/glass substrate, 100 nm of molybdenum trioxide (MoO₃) (Alfa Aesar) was thermally evaporated. The MoO₃/ITO/glass substrate was then annealed at 350°C for 6 hours under ambient conditions. An ionic gel solution consisting PVDF-HFP (Sigma-Aldrich), LiTFSI salt (Sigma-Aldrich), and acetone (Sigma-Aldrich) in an 8:1:56 ratio was prepared. Subsequently, this ionic gel solution was spin-coated at 1500 rpm for 60 s. After a bake at 80°C for 2 hours, a solution of P3HT (10 mg/ml; EMNI) was spin-coated at 1500 rpm for 60 s. After another bake at 120°C for 30 min, gold (40 nm) was thermally evaporated to form the source and drain electrodes through shadow masks. The fabricated synaptic device was electrically connected to the olfactory sensory neuron device using silver paste and gold wire.

Linear PEO, hyperbranched (third and sixth
generation) PEO, and lithium bis(trifluoromethane)sulfonamide, LiTFSI
salt, were purchased from Sigma-Aldrich. Four-arm and eight-arm star
PEOs were supplied by Creative PEGWorks. All polymers were used as
received without modification. The polymer characteristics are displayed
in Table 1. The chemical
structure of the PEOs with hydroxyl end groups is provided in Figure S1.