In search of a new design strategy for solid single-component organic ferroelectrics: Polar crystalline phases formed by bent-core molecules

Abstract

A new design strategy for solid single-component organic ferroelectrics and pyroelectrics has been developed. The subject is based on five-ring bent-core compounds which have the chemical structure typical for banana-shaped liquid crystals, however, they do not form liquid crystalline phases. Starting from a parent compound, systematic variation of different molecular moieties has lead to the chemical structure forming liquid crystalline compounds and which results in materials exhibiting crystalline modifications only. Calorimetric and polarizing microscopic investigations, X-ray diffraction measurements, dielectric, electro-optic and SHG studies have been used to characterize the new materials. More than 50% of the compounds which do not exhibit a liquid crystalline phase show ferroelectric and/or pyroelectric behaviour in different solid modifications.