Optimization of Polyelectrolyte and Polymers in Inorganic/Organic Hybrid Gate Dielectrics for Flexible OFETs

In this work, bilayer hybrid gate dielectric with various polymers and polyelectrolyte dielectrics such as poly(vinylidene fluoride–trifluoroethylene) (P(VDF-TrFE)), PVP-Co-poly(methyl methacrylate) (PMMA), and poly-acrylic acid (PAA) were explored in combination with a thin high- ${k}$ hafnium oxide (HfOx) grown by atomic layer deposition (ALD) for the demonstration of high-performance flexible organic field-effect transistors (OFETs). Solution-processed 6,13-bis(triisopropylsilylethynyl) (TIPS)-pentacene was used as an active layer to fabricate p-channel devices, which operated at −10 V with decent ${I} _{\mathrm{\scriptscriptstyle ON}}/{I} _{\mathrm{\scriptscriptstyle OFF}}$ values ranging from $\sim 10^{4}$ to $\sim 10^{3}$ for all three cases. The devices with HfOx/PAA dielectric exhibited better performance compared to other counterparts due to higher capacitance density, along with excellent cyclic stability with fast dynamic switching over continuous 500 cycles. Moreover, these devices showed high electrical stability upon the application of bending to the channel direction upon different radii up to 5 mm causing tensile stress. Further, devices were also used in resistive-load inverter circuits to assess the switching behavior, showing decent static and dynamic switching.