Together with the group of Kasper Moth-Poulsen at Chemistry, we recently published several papers concerning the design of molecular solar thermal systems (MOST), one of which was highlighted on the cover of ChemSusChem. These materials could lead to an attractive solution for grid solar energy storage solutions that deserves further exploration. The concept is based on photoswitchable molecules that are designed to store solar energy and release on demand in the form of heat.
Several criteria need to be satisfied in an efficient MOST system. Importantly, the molecular weight should be as low as possible and at the same time the molecules should absorb a large fraction of the solar spectrum. These requirements lead to an exceedingly large parameter space of possible target structures and difficult compromises in molecular design that are challenging to optimize by molecular engineering through synthesis. Computational modelling offers an effective solution to this problem, which motivated this collaboration between theory and experimental research groups.
Specifically we investigated MOST materials based on substituted norbornadiene compounds. In the first paper we studied various properties of importance using quantum chemical calculations at different levels of theory. Based on this work we then conducted a computational screening of 64 norbornadiene compounds and provided theoretical support for the development of novel systems with optimized absorption properties. In the third paper a series of novel compounds was synthesized where we could demonstrate the origin of the enhanced absorption by means of quantum mechanical calculations.