Solution-processed 10 nm thick ferroelectric polymer film on a TiO2 nanolayer for flexible nonvolatile memories

Abstract

Poly(vinylidene fluoride)-based ferroelectric polymers, known for their exceptional flexibility, cost-effectiveness, and ease of processing, have garnered significant attention in the field of nonvolatile data storage. However, a persistent challenge lies in their elevated driving voltage and subpar thermal stability, leading to excessive power consumption and restricted operational conditions. Herein, we propose a flexible ferroelectric random access memory (FeRAM) based on a ceramic/polymer bilayer consisting of a solution-processed ferroelectric poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] nanofilm on top of a TiO2 nanolayer. The polarized Fourier transform infrared spectroscopy spectra and piezoresponse force microscopy phase signals demonstrate that the surface effect of the underlying TiO2 induces a consistent dipole orientation along the out-of-plane direction in the P(VDF-TrFE) nanofilm. These aligned dipoles in the P(VDF-TrFE) can be efficiently switched by a low driving voltage of 5 V while maintaining a high thermal stability exceeding 100 °C. Furthermore, the FeRAM based on the TiO2/P(VDF-TrFE) bilayer exhibits a remarkable storage density of approximately 60 GB in.–2, coupled with exceptional flexibility, high transparency, and superior read/write durability. These outstanding performances indicate that the TiO2/P(VDF-TrFE) bilayer holds significant potential for applications in high-density information storage within flexible electronics.