A Ferroelectric Minus The Metal

Barium titanate and other ferroelectric materials are prized for their ability to switch their polarization when an external electric field is applied. This makes them useful for a variety of applications, including medical imaging, computer memory, and solar energy harvesting. The problem is that metal oxide ferroelectrics are difficult to process into films and often contain toxic metals. Now researchers report that crystals of the organic salt diisopropylammonium bromide, or DIPAB, have ferroelectric properties on par with those of barium titanate (Science, DOI: 10.1126/science.1229675). Although organic ferroelectrics have been known for nearly 100 years, none have proved to possess the properties of their metal oxide cousins, until now. A team led by Ren-Gen Xiong of China’s Southeast University and Jiangyu Li of the University of Washington, Seattle, went hunting for an organic material with structural features that lend themselves to ferroelectricity as well as a high melting point. They found that DIPAB had spontaneous polarization similar to that of barium titanate as well as several other benchmark ferroelectric features. Furthermore, DIPAB can be processed from aqueous solution, making it easy to use and sustainable.