Asymmetric polarization and hysteresis behaviour in ferroelectric P(VDF-TrFE) (76:24) copolymer thin films spatially resolved via LIMM

作者：Putzeys T; Wuebbenhorst M^*

来源：Physical Chemistry Chemical Physics, 2015, 17(12): 7767-7774.

DOI：10.1039/c4cp06033d

The concept of charge-polarization coupling in the ferroelectric copolymer PVDF-TrFE (poly[ vinylidene fluoride-co-trifluoroethylene]) has been revisited by employing high resolution (<50 nm) pyroelectric depth profiling (LIMM). By virtue of probing the pyroelectric activity over the film thickness in the presence of a variable, external electrical field, the local ferroelectric response and spatially resolved hysteresis could be obtained. A large asymmetry was found between the positive and negative electrode-polymer interface. Differences in amplitude of polarization, contribution of interface charges and length scale of the polarization-free zone near the electrodes suggest a higher availability of compensation charges at the negative electrode that finally stabilize the local polarization. The resulting asymmetries in the polarization distribution are hence attributed to excess charges as a result of electron injection as a specific charge generation mechanism at the negative electrode.

• 出版日期2015