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Will soap and sunlight solve the energy problem?

A consortium of international researchers comes with a unique solution to the energy problem. By mimicking photosynthesis, they aim to produce sustainable fuels out of sunlight, water, and CO2. Their secret? ‘Soap bubbles’, says Leiden chemist Sylvestre Bonnet, who is part of the consortium.

Inspired by nature

Photosynthesis is a process in which plants convert carbon dioxide, sunlight and water into glucose and dioxygen. Many scientists try to mimic this process, in order to produce renewable energy. So does the international consortium SoFiA, which aims at producing solar fuels through artificial photosynthesis. Fuels are 1-2 orders of magnitude more energy dense than the best batteries, making them the best way to store solar energy. 

Soap films

SoFiA comes with an innovative approach which involves soap films. The researchers aim to mimic the light-sensitive part of leaves called the thylakoid membrane. The soap films will be doped with photosensitizers and catalysts: molecules that, when put together in the confined space of the soap film, will convert carbon dioxide into fuel with sunlight. Soap films are easy to make and are easy to functionalize with light-sensitive molecules. In addition, they can be recycled, because they simply self-assemble. Unlike other concepts of artificial leaves, with soap films there is no need to perform difficult chemical synthesis to attach functional molecules to each other and to the film. Also, because soap films are so thin, they only absorb part of the sunlight energy arriving on them and – similar to leaves in a tree – let the excess light propagate to the next film.

Project SoFiA

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Leiden involved

Associate professor Sylvestre Bonnet is part of the 3.2 million euros project with two postdoc positions. ‘My new postdoc Andrea Pannwitz started on 1 March. She is a German researcher who did her PhD on photochemistry in Switzerland. Later on, a second postdoc will follow’, Bonnet says. But Bonnet himself is not the only Leiden partner. ‘The Fine Mechanical Department (FMD) here in Leiden is an essential partner in the project, because they can build almost anything.’ Before the project was funded, the FMD collaborated with Bonnet and designed an experimental set-up, which allows to study soap films doped with photosensitive compounds. ‘This setup has laid the foundation for the start of the project; the FMD is now making several identical setups that will be shipped to the other European partners, so that we can compare data generated in different laboratories.’

Crossing boundaries

The SoFiA project manager Indraneel Sen points out what makes this project special: ‘SoFiA bridges distant scientific disciplines with business management, environmental and socio-political sciences, and fine arts.’ According to the press release of Uppsala University ‘SoFiA intrinsically crosses traditional collaborative boundaries. For the first time, it bridges mutually exclusive disciplines of surfactant science, solar fuels, and fundamental science of water at nanoscale – initiating their mutual learning, cross-fertilization and synergistic advances.’  

Vici grant

Earlier this year, photochemist Bonnet received a Vici grant. With this grant he aims to inhibit cancer proteins with metal-containing medicines and light, potentially greatly reducing the side-effects of cancer treatments. In addition, Bonnet is involved in the project LogicLab. This recently started project focuses on diagnosing diseases with molecular switches in the body. 

The project SoFiA, officially called ‘Soap Film based Artificial Photosynthesis’, is funded from the FET OPEN 2018 call within the Horizon 2020 programme. The consortium is coordinated by Professor Leif Hammarström from Uppsala University in Sweden. It features eight partner institutions from six different countries, including the Dutch institute AMOLF. SoFiA started 1 January 2019 and will last for four years. 

This  project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement number 828838. 
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