Dipole switching dynamics in P(VDF-TrFE) film revealed by in-situ polarization switching and infrared spectroscopy measurements with high-time resolution
Kohki Uneda, Shohei Horike, Yasuko Koshiba, Kenji Ishida
Abstract
Although P(VDF-TrFE) is an important ferroelectric material, its polarization switching details, especially at the nucleation site of the polarized domain, are unknown. Herein, a setup combining a ferroelectricity evaluation system and a Fourier-transform infrared spectrometer with a 70 ms time resolution was developed to simultaneously monitor polarization-switching current and absorption changes associated with the molecular chain rotation of P(VDF-TrFE) under an electric field. Time variations of absorbance associated with CF2 symmetric vibration in response to the applied electric field served as an indicator of dipole rotation. The onsets and peaks of the polarization-switching current, which appeared before the dynamic molecular orientation, changed across the material. The complementary characterization revealed that the P(VDF-TrFE) polarized domain first nucleates at the interface and grows toward the inner side of film to achieve a completely polarized state of the film.