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A universal model and experiments on the polarization switching for ferroelectric poly(vinylidene fluoride-trifluoroethylene) copolymer ultra-thin films with an interface layer have been studied. It is found that polarization switching could complete if the capacitance of the interface layer is large enough compared with that of the ferroelectric film. Based on this model, a conducting polymer, poly(3,4-ethylene dioxythiophene)-poly(styrene sulfonic) acid, is introduced as an interface layer between metal electrodes and ferroelectric polymer film and the switching property measurements well agree with the simulation results of the model. These findings provide an effective route to enhance the polarization switching for the ferroelectric films, which is promising for potential applications. [ABSTRACT FROM AUTHOR]

The characteristics of ferroelectric capacitors with poly(vinylidene fluoride-trifluoroethlene) (P(VDF-TrFE)) films have been studied at different structures of cell electrodes. It is suggested that the effect of electrode structures could induce changes of performance. Remarkably, cells with line electrodes display a better polarization and fatigue resistance than those with flat electrodes. For P(VDF-TrFE) ultrathin films with different electrode structures, the models of charge compensation mechanism for depolarization field and domain fatigue decomposition are used to explain the effect of electrode structure. Furthermore, the driving voltage based on normal speed-functionality is designed, and the testing results show that the line electrode structure could induce a robust switching, which is determined by the free charges concentration in active layer. These findings provide an effective route to design the optimum structure for a ferroelectric capacitor based on P(VDF-TrFE) copolymer ultrathin film. [ABSTRACT FROM AUTHOR]

A series of ferroelectric polarization reversal measurements have been conducted on spin-coated ultrathin poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer films sandwiched with different electroactive materials between P(VDF-TrFE) and metal electrodes. Three types of electroactive interlayers, including highly polarizable material copper-phthalocyanine (CuPc), electron conductive polyethylene dioxythiophene/poly(styrene sulfonate acid), and ion (proton) conductive poly (vinyl phosphonic) acid, have been employed in our experiment. In addition, the ferroelectric film with CuPc exhibits larger remnant polarization and the enhancement of fatigue resistance although higher drive voltage and more switching time can be observed, which differs from the samples with electron and proton conductors as interlayers. The further analysis shows that this may be attributed to higher dielectric constant of CuPc than that of P(VDF-TrFE) layer. These results suggest that three types of interlayers can lead to a large improvement of ferroelectric switching, which is promising for potential applications. [ABSTRACT FROM AUTHOR]

The polarization switching and imprint behaviors with different pulse and unipolar poling processes for ferroelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) copolymer ultrathin films have been studied. Compared with results for samples only through the certain protocol we studied previously, the much faster switching speed and lower voltage shift are observed for films with certain protocol as well as certain unipolar poling. The analyses show that these properties are strongly dependent on the directions of the switching and unipolar poling field. The results provide another effective route to design the optimum protocol for ferroelectric random access memory based on P(VDF-TrFE) copolymer ultrathin film. [ABSTRACT FROM AUTHOR]