Subject a positive voltage over a ferroelectric material for a short period of time and the material will remember: the crystal structure of the material itself rearranges and gets permanently polarized. This polarizability makes ferroelectrics immensely useful; they can be used in computers memory and as as sensors, displays, transducers, and energy harvesters.
In the transition to a more sustainable society there is one issue: standard ferroelectrics today are ceramic materials made of scarce or toxic heavy metals with high processing costs. However, there is an option that could be viable in many niches: Build the crystals out of small eco-friendly organic molecules rather than atoms. While such materials are currently sub-par the inorganics ones, they are largely unexplored and there are almost endless ways of tuning, optimizing, and combining organic molecules, giving them an enormous potential. Moreover, the super-molecular nature of organic ferroelectrics can offer novel functionalities providing new and interesting ways of utilizing ferroelectric materials.
One project aim is to identify all promising organic ferroelectrics from all known organic crystals, about one million in total. Currently, we are using several schemes to reduce this to a more manageable one and we use data analysis to automatically weed out those with unfavorable properties. For smaller materials pools we have started use advanced quantum mechanical to predict their properties accurately and understand their properties.
But we will not stop there. Based on these materials, we will design new hypothetical materials and predict their properties in the same manner as with existing materials. Finally, we will carefully select a few highly promising compounds that will be synthesized in the lab and experimentally measured to determine whether they could be the next materials for more sustainable electronic devices.
Ferroelectric organic molecular crystals have the potential to replace current inorganic materials used in ferroelectric random access memory (FeRAM) which could significantly reduce fabrications costs and reliance on toxic
or scarce chemical elements. It can also extend the usage of organic ferroelectrics to other niches. However, compounds with a larger ferroelectric-paraelectric phase transition temperature is urgently needed to bring this promise into fruition. In addition, modest coercive fields and sizeable polarization is needed. However, a deeper understanding of their physical properties is required and so is also a systematic design approach. The Fox project will obtain such insight by using sophisticated modelling methods and comparison with experimental results. Moreover, we will systematically design new organic ferroelectrics in a reliable manner to improve performance. The most promising candidates will be crystallized and in turn characterized both by the project group and by collaborators, which will provide further understanding and the potential for realizing record-breaking organic ferroelectrics. Computational-guided discovery, with experimental and characterization, has in recent years proven itself as a powerful approach for engineering new materials, but organic ferroelectric molecular crystals have been largely been overlooked. We have assembled a strong team of scientists and international collaborators, with access to, and experience with, a range of different characterization methods needed for in-depth analysis of these compounds.