Amide-based discotic supramolecular organic materials are of interest for fundamental understanding of cooperative self-assembly and collective dipole switching mechanisms as well as for practically relevant ferroelectric and piezoelectric properties. Here, we show how replacing amides (dipole moment of similar to 3.5 D) with thioamides (similar to 5.1 D) as dipolar moieties in the archetypal C-3-symmetric discotic molecule BTA leads to ferroelectric materials with a higher remnant polarization and lower coercive field. The thioamide-based materials also demonstrate a rare negative piezoelectricity and a previously predicted, yet never experimentally observed, polarization reversal via asymmetric intermediate states, that is, ferrielectric switching.
Funding Agencies|Vetenskapsradet [2015-03813]; Santander Talent Attraction Research (STAR2); Spanish MINECO [PID2021-125429NA-I00]; Carl Zeiss Foundation