Templated assembly of photoswitches significantly increases the energy-storage capacity of solar thermal fuels

Accelerating the design of solar thermal fuel materials through high throughput simulations

Solar thermal fuels (STF) store the energy of sunlight, which can then be released later in the form of heat, offering an emission-free and renewable solution for both solar energy conversion and storage. However, this approach is currently limited by the lack of low-cost materials with high energy density and high stability. In this Letter, we present an ab initio high-throughput computational approach to accelerate the design process and allow for searches over a broad class of materials. The high-throughput screening platform we have developed can run through large numbers of molecules composed of earth-abundant elements and identifies possible metastable structures of a given material. Corresponding isomerization enthalpies associated with the metastable structures are then computed. Using this high-throughput simulation approach, we have discovered molecular structures with high isomerization enthalpies that have the potential to be new candidates for high-energy density STF. We have also discovered physical principles to guide further STF materials design through structural analysis. More broadly, our results illustrate the potential of using high-throughput ab initio simulations to design materials that undergo targeted structural transitions.

A liquid azobenzene derivative as a solvent-free solar thermal fuel

A liquid solar thermal fuel is developed; a low-molecular weight liquid trans-azobenzene derivative shows facile photoisomerization to the higher-energy cis-isomer in neat condition so that a high volumetric energy density is achieved. Shear viscosity measurements for each isomer liquid unveiled transitions from non-Newtonian to Newtonian fluids.