title: Optimization of Norbornadiene Compounds for Solar Thermal Storage by First-Principles Calculations.
abstract: Molecular photoswitches capable of storing solar energy are interesting candidates for future renewable energy applications. Here, using quantum mechanical calculations, we carry out a systematic screening of crucial optical (solar spectrum match) and thermal (storage energy density) properties of 64 such compounds based on the norbornadiene-quadricyclane system. Whereas a substantial number of these molecules reach the theoretical maximum solar power conversion efficiency, this requires a strong red-shift of the absorption spectrum, which causes undesirable absorption by the photoisomer as well as reduced thermal stability. These compounds typically also have a large molecular mass, leading to low storage densities. By contrast, single-substituted systems achieve a good compromise between efficiency and storage density, while avoiding competing absorption by the photo-isomer. This establishes guiding principles for the future development of molecular solar thermal storage systems.
authors.affiliation: Department of Physics, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Mikael
authors.initials: M
authors.lastname: Kuisma
authors.affiliation: Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Angelica
authors.initials: A
authors.lastname: Lundin
authors.affiliation: Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Kasper
authors.identifier: 0000-0003-4018-4927
authors.initials: K
authors.lastname: Moth-Poulsen
authors.affiliation: Department of Microtechnology and Nano Science, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Per
authors.identifier: 0000-0001-5810-8119
authors.initials: P
authors.lastname: Hyldgaard
authors.affiliation: Department of Physics, Chalmers University of Technology, Gothenburg, Sweden. erhart@chalmers.se.
authors.forename: Paul
authors.identifier: 0000-0002-2516-6061
authors.initials: P
authors.lastname: Erhart
mesh_terms: D001896:Boron Compounds / Q000737:chemistry*; D016208:Databases, Factual; D011211:Electric Power Supplies; D012993:Solar Energy
chemical_list: D001896:Boron Compounds
keywords: density functional theory; norbornadiene; quadricyclane; solar-thermal storage; storage density