Above-room-temperature ferroelectricity in a single-component molecular crystal

Ferroelectricity goes organic Ferroelectric compounds have a range of properties useful in practical applications, including polarity reversal in electric fields, temperature sensitivity and the ability to convert mechanical stress into electricity. It is generally assumed that ferroelectricity is rare and mostly poor in organic compounds, but Horiuchi et al. now report the discovery of above-room-temperature ferroelectricity with relatively high polarization in the organic crystal croconic acid, a component of black dyes. These properties are not readily apparent in the crystalline form of this simple molecule, but they emerge on application of a modest electric field that induces a molecular-topological keto-enol conversion. This finding raises the prospect that organic ferroelectrics might be much more abundant that previously thought.