Solid-State Electrolyte Dielectrics Based on Exceptional High-k P(VDF-TrFE-CTFE) Terpolymer for High-Performance Field-Effect Transistors

High-performance and low-voltage organic and inorganic field-effect transistors (FETs) with solid-state electrolyte gate insulator that is composed of an exceptional high-k fluorinated dielectric and an ion-gel-blend polymer matrix are reported. The structuring polymer is high-k poly(vinylidenefluoride-trifluoroethylene-chlorotrifluoroethylene) (P(VDF-TrFE-CTFE)) terpolymer. The ion gel is made of poly(vinylidene fluoride-co-hexafluroropropylene) (P(VDF-HFP)) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([EMIM][TFSI]) ion liquid. The blend polymer matrix has high measured capacitance of ≈2 to 5.5 µF cm⁻² at 100 Hz, which is attributed to formation of electrical double layers (EDLs) at the insulator/semiconductor interface. High effective carrier mobility (μ_eff) and low operating voltage ≤2 V with just 0.5 v% of P(VDF-HFP)-[EMIM][TFSI] solution in the bulk P(VDF-TrFE-CTFE) insulating layer are demonstrated, coupled with low gate-leakage current levels. Excellent μ_eff = 1.30 ± 0.19 cm² V⁻¹ s⁻¹ is achieved in P3HT FETs with SEGI, which is a remarkable boost from 0.48 ± 0.09 cm² V⁻¹ s⁻¹ at 30 V when pure P(VDF-TrFE-CTFE) dielectric is used. Other semiconductors are also tested: IGZO has μ_eff = 11.09 ± 2.07 cm² V⁻¹ s⁻¹, and PDFDT has μ_eff = 2.42 ± 0.46 cm² V⁻¹ s⁻¹. These remarkable increases in mobility are attributed to the high concentration of induced carriers in the semiconducting channel.