It’s a massive demonstration of the quality of this material and opens the door to maximising the efficiency of solar cells.
- Felix Deschler
Scientists have discovered that a highly promising group of materials known as hybrid lead halide perovskites can recycle light – a finding that they believe could lead to large gains in the efficiency of solar cells.
Hybrid lead halide perovskites are a particular group of synthetic materials which have been the subject of intensive scientific research, as they appear to promise a revolution in the field of solar energy. As well as being cheap and easy to produce, perovskite solar cells have, in the space of a few years, become almost as energy-efficient as silicon – the material currently used in most household solar panels.
By showing that they can also be optimised to recycle light, the new study suggests that this could just be the beginning. Solar cells work by absorbing photons from the sun to create electrical charges, but the process also works in reverse, because when the electrical charges recombine, they can create a photon. The research shows that perovskite cells have the extra ability to re-absorb these regenerated photons – a process known as “photon recycling”. This creates a concentration effect inside the cell, as if a lens has been used to focus lots of light in a single spot.
According to the researchers, this ability to recycle photons could be exploited with relative ease to create cells capable of pushing the limits of energy efficiency in solar panels.
The study builds on an established collaboration, focusing on the use of these materials not only in solar cells but also in light-emitting diodes, and was carried out in the group of Richard Friend, Cavendish Professor of Physics and Fellow of St John’s College at the University of Cambridge. The research was undertaken in partnership with the team of Henry Snaith at the University of Oxford and Bruno Ehrler at the FOM Institute, AMOLF, Amsterdam.
Felix Deschler, who is one of the corresponding authors of the study and works with a team studying perovskites at the Cavendish Laboratory, said: “It’s a massive demonstration of the quality of this material and opens the door to maximising the efficiency of solar cells. The fabrication methods that would be required to exploit this phenomenon are not complicated, and that should boost the efficiency of this technology significantly beyond what we have been able to achieve until now.”
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Image: Depiction of photon recycling inside the crystalline structure of perovskite.
Credit: Criss Hohmann
Reproduced courtesy of the University of Cambridge
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