Spectroscopic analysis of the electric field induced structural changes in vinylidene fluoride/trifluoroethylene copolymers

Ferroelectric Properties and Polarization Switching Kinetic of Poly (vinylidene fluoride-trifluoroethylene) Copolymer

“…Each phase of the P(VDF-TrFE) polymer will provide a characteristic FT-IR spectrum. Details of the absorption band assignments can be found in the literature [Kobayashi et al, 1974;Reynolds et al, 1989;Kim et al, 1989]. Here we only discuss the three intense bands, 1288 cm -1 , 850 cm -1 , and 1400 cm -1 associated with the phase of P(VDF-TrFE).…”

Stability of polarization in organic ferroelectric metal-insulator-semiconductor structures

“…However, a similar phenomenon was reported by Guy et al 39 for PVDF and attributed to the conformational transition of the crystal structure of Form II (α-PVDF) towards Form I (β-PVDF). The studies of Reynolds et al 104 on P(VDF-TrFE) on the other side might lead to the conclusion that this built up of polarization is attributed to the alignment of ferroelectric domains by the electric field. Based on this, it could be theorized that during the first cycles the movability of the ferroelectric domains has been increased, leading to a gradual increase of polarization.…”

“…29,34,45,46,49,74,83,104,119,128,129,140 It was found by Sasabe et al 107 that PVDF shows three relaxations. In the TSC measurements, the α a -relaxation at around −30 ○ C corresponds to the glass transition and is attributed to the micro-Brownian motion of the amorphous phase, the α c -relaxation is assigned to molecular motions in the crystalline regions of α-PVDF and is found at 80 ○ C. At temperatures of around −50 ○ C and at frequencies between 100 Hz and 1 kHz the dielectric spectra reveal the β-relaxation attributed to local motions within the frozen main chains in the amorphous regions.…”

“…The spincoating was followed by a drying process under vacuum at 110 ○ C for 12h in order to promote crystallization and further evaporation of residual solvents. 17,59,60,77,104,136 Concerning the annealing temperature, Xia et al 136 and Naber et al 77 have shown that annealing above 140 ○ C may lead to a decrease of remanent polarization in thin films. This phenomenon occurs in thin P(VDF-TrFE) films only and is attributed to the reduction of the crystal size for low annealing temperatures below 140 ○ C. 136 Xia et al also pointed out that the use of a moderate annealing temperature leads to decreased switching times of the ferroelectric domains.…”

Voltage-induced Infrared Absorption from a Spin-cast Thin Film of Ferroelectric Poly(vinvlidene fhioride-co-trifluoroethvlene) (P(VDF-TrFE))

“…External electric field effects on the infrared spectra of materials give rise to the vibrational Stark effect, [1][2][3][4] orientation polarization in solutions [5][6][7][8][9] and ferroelectric solids, [10][11][12][13][14][15][16] as well as other effects. In previous work, we demonstrated that the voltage-induced infrared spectra from organic field-effect transistors are due to the carriers generated in organic semiconductors by the field effect.…”