Professor Dr Michael Grätzel

Research Priorities: nanocrystalline junctions, photovoltaic cells, photon energy conversion and storage, lithium-ion batteries, molecular switches and displays, photocatalysis
Michael Grätzel is a German chemist. He conducts research on photonics and has made a name for himself by developing a new type of solar cell (“Grätzel cell”) that notably performs better in low light.
For the absorption of light energy, the Grätzel cell does not use inorganic semi-conductor materials but organic dye. Michael Grätzel was able to take photovoltaics to the molecular level, moving beyond light-absorbing diodes. His revolutionary cell design represented a new paradigm because – in contrast to the planar p-n-junctions of conventional solar cells – it features three-dimensional mesoscopic junctions.
The prototype of this new photovoltaics approach is the dye-sensitized solar cell (DSC) that uses dye molecules, pigments and quantum dots to harvest sunlight. DSCs are the first and only photovoltaic system that separates light absorption from charge carrier transport. It is also the only photovoltaic technology that mimics photosynthesis to produce electricity. DSCs are easy and inexpensive to produce and they offer unique and practical advantages such as flexibility, aesthetic appeal, transparency, and bifacial photon collection. Currently, they achieve an energy conversion efficiency of almost 15 percent in full sunlight and 32 percent in ambient light. These properties and excellent long-term stability have enabled commercial applications on an industrial scale. The production of these cells is less expensive than that of conventional silicon-based solar cells and they notably perform better in low light.