Towards a new type of solar cell

© 2014 EPFL

© 2014 EPFL

EPFL scientists have uncovered how lead iodide perovskite semiconductor transfer electrical charges to other materials upon irradiation. The milestone discovery allows for a better understanding of the functioning of revolutionary photovoltaic cells with unprecedented power conversion efficiency.

Solar cells that use lead iodide pervoskites as their light-absorbing material have gained immense interest lately because of their high power conversion efficiency, which exceeds 16%. However, a detailed description of how these solar cells turn light into electrical current is still lacking. Publishing in Nature Photonics, scientists from EPFL have investigated how the generated electrical charges are transferred at the perovskite surface.

Using ultrafast laser spectroscopy and microwave photoconductivity on solar cells of different architectures, the scientists were able to observe the dynamics of photo-generated charges. This allowed them to unravel a unique charge separation mechanism, making perovskite solar cells a new type of photovoltaic converter of its own and a new realm of scientific investigation and techno-logical development.

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