Professor Marsan has come up with solutions for two problems that, for the last twenty years, have been hampering the development of efficient and affordable solar cells.

The Earth receives more solar energy in one hour than the entire planet currently consumes in a year. Unfortunately, despite this enormous potential, solar energy is barely exploited. The electricity produced by conventional solar cells, composed of semiconductor materials like silicon, is 5 or 6 times more expensive than from traditional energy sources, such as fossil fuels or hydropower. Over the years, numerous research teams have attempted to develop a solar cell that would be both efficient in terms of energy and inexpensive to produce.

One of the most promising solar cells was designed in the early '90s by Professor Michael Graetzel of the Ecole Polytechnique Federale de Lausanne (EPFL) in Switzerland. Based on the principle of photosynthesis -- the biochemical process by which plants convert light energy into carbohydrate (sugar, their food) -- the Graetzel solar cell is composed of a porous layer of nanoparticles of a white pigment, titanium dioxide, covered with a molecular dye that absorbs sunlight, like the chlorophyll in green leaves. The pigment-coated titanium dioxide is immersed in an electrolyte solution, and a platinum-based catalyst completes the package.

(Science Daily)

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