Switzerland/Germany

Michael Grätzel

2009 Balzan Prize for the Science of New Materials

For his many contributions to the science of new materials, and in particular for his invention and development of a new type of photovoltaic solar cell, the dye-sensitized Cell, commonly known as the Grätzel cell.

Professor Grätzel is the inventor of a whole new class of solar cells, devices that are intended to transform the sun’s energy into electricity. In a Grätzel cell, quanta of light from the sun are captured by dye molecules, which release electrons to a network of semiconductor oxide nanoparticles. This process generates the energy for electricity. The dye sensitized cell thus mimics the natural process used by green plants in photosynthesis, with the sensitising dye playing the part of chlorophyll. In plants, the sun’s
energy is used to manufacture sugars, whilst in the Grätzel cell it is used to make electricity.
In contrast to the commonly used silicon cells, which require highly purified and expensive silicon, Grätzel cells use relatively inexpensive materials, and represent one of the most promising approaches to the exploitation of solar energy. The Grätzel cell is an efficient and stable converter of sunlight into electricity. Because it is cheap to manufacture, it is likely to be of particular importance in generating electricity on small scales in the developing world. A company in Wales is now manufacturing the cells on a commercial scale.
His recent work includes groundbreaking discoveries on the solar production of hydrogen, which could represent a revolution in the use of solar energy, allowing its transformation and storage under the form of a very flexible fuel.
Professor Grätzel is a most appropriate Balzan laureate for his fundamental discoveries that also have important practical applications in the production of sustainable energy.