Pyroelectricity of Ferroelectric Vinylidene Fluoride-Oligomer-Evaporated Thin Films

The pyroelectricity of ferroelectric vinylidene fluoride (VDF)-oligomer [CF 3 (CH 2 CF 2 ) 17 I]-evaporated film was investigated utilizing a low-frequency sinusoidal heat source. A current profile appeared as the summation of a fundamental sine wave with a frequency of the temperature change and its harmonic responses. The pyroelectric coefficient ( p ) of the 600-nm-thick VDF oligomer film was estimated to be -68 µC/m 2 K at 37°C, whose absolute value is larger than those reported for ferroelectric polymers. Various characteristics such as a large | p |, a small dielectric constant and suitability for preparation of thinner films suggest that the VDF oligomer is a promising material for application in pyroelectric thin-film infrared detectors.