EES Blog

Scientists in Germany have developed a highly targeted metabolic engineering technique to control the flow of electrons produced by the initial stages of photosynthesis in microalgae, and used it to increase hydrogen production by a factor of five.

Hydrogen is increasingly being touted as an environmentally friendly alternative to conventional fossil fuels, but, ‘at present, hydrogen is mainly produced from natural gas, which makes it a “wolf in sheep’s clothing”,’ comments Oliver Inderwildi, a senior policy fellow at the Smith School of Enterprise and the Environment, University of Oxford, UK. Natural microalgae produce hydrogen by harnessing energy from sunlight, but their low production rate limits their practical application. Organisms typically use most of the electrons they generate to make the carbohydrates they need to live.

Previous studies in this area had focussed on curbing carbohydrate production. Now, Wolfgang Lubitz, of the Max Planck Institute for Chemical Energy Conversion, and co-workers have modified a ferredoxin protein responsible for distributing photo-generated electrons in the green algae Chlamydomonas reinhardtii with the aim of boosting its hydrogen output, whilst allowing the organism to be self-sustaining.

Interested to find out more? Read the full article by Jonathan Midgley in Chemistry World.

Read the original article in Energy & Environmental Science:

Enhancing hydrogen production of microalgae by redirecting electrons from photosystem I to hydrogenase
Sigrun Rumpel, Judith F. Siebel, Christophe Farès, Jifu Duan, Edward Reijerse, Thomas Happe, Wolfgang Lubitz and Martin Winkler
Energy Environ. Sci., 2014, Advance Article
DOI: 10.1039/C4EE01444H

A low-cost, high-efficiency technique for fabricating perovskite solar cells – ultra-sonic spray-coating – has been developed by a team of researchers in the UK. It represents a significant step towards commercialising perovskite solar cells.

David Lidzey, head of the research group at the University of Sheffield behind the study, explains that there has been ‘interest in developing solar cell materials that are easy to process, efficient and have less embodied energy than current technologies.’

Thin-film solar cells using perovskite semi-conductors have become a promising form of photovoltaic device achieving power conversion efficiencies of up to 15–19%, surpassing the efficiencies of amorphous silicon and organic semi-conductor photovoltaics.

Perovskite films can be fabricated by depositing precursor materials from solution. However, there have been few reports detailing the application of scalable solution-processing techniques to create these films.

In this study, an ultra-sonic spray-coating of methylamine iodide and lead chloride created a thin film of a perovskite precursor under ambient conditions. The film was then thermally annealed into a CH3NH3PbI3–ᵪClᵪ perovskite structure prior to inclusion within a solar cell with a planar heterojunction architecture.

Interested to find out more? Read the full article by Vicki Marshall in Chemistry World.

Read the original article in Energy and Environmental Science:

Efficient planar heterojunction mixed-halide perovskite solar cells deposited via spray-deposition
Alexander T. Barrows, Andrew J. Pearson, Chan Kyu Kwak, Alan D. F. Dunbar, Alastair R. Buckley and David G. Lidzey
Energy Environ. Sci., 2014, Advance Article
DOI: 10.1039/C4EE01546K