published on 12 June 2018 in energy

Silicon and perovskite, a new record for photovoltaic technology

In Neuchâtel, in Switzerland, a new record has been achieved by a combination of conventional photovoltaic technology with the latest generation of solar cells. Researchers at the École Polytechnique Fédérale in Lausanne (EPFL) and the Centre Suisse d’Electronique et de Microtechnique (CSEM) have created silicon-perovskite solar cells with a conversion efficiency of 25.2%. Yet efficiency is not the only advantage of these cells: in fact, the researchers have perfected an economical and simple production process, that can be directly integrated into existing production lines, simply by updating those making silicon solar cells.

Silicon pyramids covered with perovskite © 2018 EPFL

In the field of photovoltaic technology, silicon-based solar cells make up 90% of the market since, in terms of cost, stability and efficiency (which may be as much as 20-22%), they are much more mature and consolidated than new technologies. However, after decades of research and investment, silicon-based solar cells are now close to their maximum theoretical efficiency, that is, it will not be possible to achieve higher efficiency while using only this type of semiconductor. One way of overcoming this limit is to create multi-junction cells, in which the use of differing semiconductor materials maximises absorption and conversion of light rays into electricity.
In the tandem solution perfected by the team of Swiss researchers, the combination of perovskite and silicon makes it possible to maximise the use of the solar spectrum and increase the quantity of energy generated, since perovskite efficiently converts blue and green light, while silicon is better at converting red and infra-red light.
At present, the research is continuing to further increase efficiency and give perovskite film greater long-term stability.

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