Water-Soluble Reactive Polymer Blends for Stable Memory Layers in Low-Voltage Nonvolatile Organic Memory Transistors...

Here low-voltage nonvolatile organic memory transistors, featuring high charge-carrier mobility and outstanding data-retention characteristics, by employing water-soluble reactive polymer blends as a gate-insulating memory layer are demonstrated. Blend films of poly(vinyl alcohol) (PVA) and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA) (PVA:PAMPSA) are prepared from their aqueous solutions with various molar ratios of PAMPSA (0-18 mol%) and thermally annealed at 70 and 110 °C. Organic field-effect transistors (OFETs) are fabricated by depositing poly(3-hexylthiophene) (P3HT) channel layers on the thermally treated PVA:PAMPSA films. Results show that the hole mobility of OFETs is remarkably increased (≈294 times at 70 °C and ≈42 times at 110 °C) by adding only 2 mol% PAMPSA to the PVA films and further improved at 10 mol% PAMPSA (>11.7 cm²  V^-1 s^-1 at 70 °C and >3.8 cm²  V^-1  s^-1 at 110 °C). The hysteresis characteristics are rather strengthened for the PVA:PAMPSA layers by annealing at 110 °C due to the formation of cross-linking sites, even though the OFETs with the pristine PVA layers do almost lose hysteresis characteristics at 110 °C. The optimized OFETs with the PVA:PAMPSA layers (10 mol%, 110 °C) deliver excellent data retention characteristics during >10 000 memory cycles at a voltage range of -5 to +5 V.