(糖心视频Org.com) -- Dye-sensitized Gr盲tzel solar cells have just set a new efficiency benchmark. By changing the composition and color of the cells, an EPFL team has increased their efficiency to more than 12%. Their results have just been published in Science.

A group of scientists in EPFL鈥檚 Laboratory of Photonics and Interfaces, under the leadership of EPFL professor Michael Gr盲tzel, has improved the efficiency of the famous Gr盲tzel solar cells to 12.3%. This performance is now comparable to silicon-based solar panels that are on the market today. And the costs of using this technology have come down slightly. Their results appeared in an article in the November 4 issue of Science magazine.

The challenge was to increase the efficiency of the dye-sensitized cells, in order to produce more electricity. To do this, the chemists replaced the standard dye components 鈥� ruthenium and iodine 鈥� with porphyrin and cobalt. This combination allows them to increase the absorption of sunlight and results in a more efficient electron exchange. It鈥檚 this exchange of electrons from the dye to the substrate that produces electricity.

Gr盲tzel cells mimic the process of plant photosynthesis, and these new dye-sensitized cells take the imitation even closer -- the new chemical combination gives them a greenish tint. This color increases the efficiency of the process that converts light energy into electricity. To get the most out of the light coming from the Sun, the cell absorbs the colors of the spectrum with the highest energies and rejects the rest, which includes the green wavelengths.

Gr盲tzel cells can be used to create flexible, transparent solar panels. They鈥檙e a promising alternative for certain applications in which traditional rigid, silicon-based panels cannot be used. In addition, this new efficiency benchmark brings them well within the efficiency range of silicon cells: the theoretical maximum efficiency of Gr盲tzel cells is now 30%, compared with 26% for silicon.