Michael Grätzel (born 11 May 1944) is a professor at the École Polytechnique Fédérale de Lausanne where he directs the Laboratory of Photonics and Interfaces. He pioneered research on energy and electron transfer reactions in mesoscopic-materials and their optoelectronic applications. He co-invented with Brian O'Regan the Grätzel cell in 1988 and pioneered the use of nanomaterials in lithium ion batteries.He won Albert Einstein World Award of Science in 2012 for Solar Energy Field.