Water-Soluble Reactive Polymer Blends for Stable Memory Layers in Low-Voltage Nonvolatile Organic Memory Transistors with High Mobility and Data-Retention Characteristics.

Abstract

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 (0-18mol%) 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 2mol% PAMPSA to the PVA films and further improved at 10mol% PAMPSA (>11.7cm2 V-1 s-1 at 70°C and >3.8cm2 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 (10mol%, 110°C) deliver excellent data retention characteristics during >10000 memory cycles at a voltage range of -5 to +5V.