On November 11th, 2011, the École Polytechnique Fédérale de Lausanne (EPFL, Ecublens, Switzerland) announced that it has reached a new efficiency record of 12.3% using dye-sensitized Grätzel solar photovoltaic (PV) cells.

Scientists under the leadership of EPFL professor Michael Grätzel, for whom the cells are named, achieved the efficiency by replacing the previously used dye components with porphyrin and cobalt.

The researchers say this increases the absorption of sunlight and results in a more efficient electron exchange. Previous cell designs used ruthenium and iodine as dye components.

Grätzel cells reach 30% theoretical efficiency

Additionally, EPFL states that it has reached a new theoretical maximum efficiency of 30% for Grätzel cells, which it notes is higher than the 26% theoretical maximum for single-junction crystalline silicon PV technologies.

The institute notes that while these cells mimic the process of plant photosynthesis, the new chemical combination also gives them a green color. This is the result of the cells absorbing the colors of visible light spectrum with the highest energies and excluding others, including the green spectrum.

Grätzel cells can be used to create flexible, transparent PV modules.

2011-11-15| Courtesy: École Polytechnique Fédérale de Lausanne | solarserver.com © Heindl Server GmbH

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