Photoswitches: a revolutionary way to store solar energy

Optimization of molecular photoswitches for solar power generation.

Molecular photoswitches that can both convert and store energy could potentially make harvesting solar energy more efficient. The research team quantum computing A method of finding molecular structures that is particularly efficient for this purpose.As the team explained in the journal Angewante ChemieTheir procedure was based on a dataset of more than 400,000 molecules that were screened to find the best molecular structures for solar energy storage materials.

MOST project: new solar energy pathways

Currently, solar energy is used directly to generate electricity or indirectly through energy stored in thermal storage. A third route could involve first storing energy from the sun in a photosensitive material and then releasing it when needed. The EU-backed project MOST (‘Molecular Solar Thermal Energy Storage’) is researching molecules such as photoswitches that can absorb and store solar energy at room temperature, in order to make the use of completely emission-free solar energy a reality. Masu.

A research team led by Kurt V. Mikkelsen of the University of Copenhagen, Denmark, and Kasper Moss Poulsen of the Polytechnic University of Barcelona-Catalunya, Spain, took a closer look at the photoswitches that are ideal for this task. They studied molecules known as bicyclic dienes, which switch to a high-energy state when exposed to light. The most prominent example of this bicyclic diene system is known as norbornadiene quadricyclane, but a vast number of similar candidates exist. The researchers explain: “The resulting chemical space consists of approximately 466,000 bicyclic dienes that we screened for potential applicability to MOST technology.”

Innovative screening methods and promising discoveries

Screening a database of this size is typically done as follows: machine learning, But this would require large amounts of training data based on real-world experiments, which the team didn’t have. Screening and evaluation of database molecules using previously developed algorithms and the new evaluation score “Eta” yielded clear results. All six of his top-scoring molecules differed from the original norbornadienequadricyclane system in important structural respects. The researchers concluded that this structural change, an enlargement of the molecular bridge between the two carbon rings of the bicyclic moiety, allowed the new molecule to store more energy than the original norbornadiene.

The researchers’ work demonstrates the potential for optimizing solar energy storage molecules. However, new molecules must first be synthesized and tested under real conditions. “Even if systems can be prepared synthetically, there is no guarantee that they will be soluble in the relevant solvents and will actually photoswitch in high yields, as we envisioned with Eta, or “There is no guarantee that there will be any optical switching at all,” the authors caution.

Impact and prospects

Nevertheless, the team developed a new large-scale training data set for machine learning algorithms, shortening difficult pre-synthetic research steps for chemists working on such systems in the future. The authors envision that this much larger reservoir of bicyclic dienes could be exploited to study photoswitches for a variety of applications, making it easier to tailor molecules to specific requirements. doing.

References: “Bicycles for Molecular Solar Energy Storage Candidates” by Andreas Arbus Hillers Bentsen, Jacob Linge Erholm, Oskar Berlin Ober, Helen Herzel, Kaspar Moss Poulsen, and Kurt V. Mikkelsen. Exploring the chemical space of formula dienes”, July 25, 2023, Angewante Chemie International Edition.
DOI: 10.1002/anie.202309543