About Prof. Michael Graetzel
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Professor of Physical Chemistry at the Ecole Polytechnique Fédérale de Lausanne, Michael Graetzel directs there the Laboratory of Photonics and Interfaces. He is also a member of the Swiss Chemical Society as well as of the European Academy of Science, a Fellow of the Royal Society of Chemistry and was elected honorary member of the Société Vaudoise de Sciences Naturelles. He pioneered research in the field of energy and electron transfer reactions in mesoscopic systems and their use in energy conversion systems, in particular photovoltaic cells and photo-electrochemical devices for the splitting of water into hydrogen and oxygen and the reduction of carbon dioxide by sunlight as well as the storage of electric power in lithium ion batteries. He discovered a new type of solar cell based on dye sensitized nanocrystalline oxide films which successfully mimic the light reaction occurring in green leafs and algae during natural photosynthesis.
His Education: • He received a doctor’s degree in Natural Science from the Technical University Berlin and honorary doctors degrees from the Universities of Hasselt, Delft, Uppsala and Turin. • Mary Upton Visiting Professor at Cornell University. • Distinguished Visiting Professor at the National University of Singapore. • Invited Professor at the University of Berkeley, the Ecole National de Chachan (Paris) and Delft University of Technology. • In 2009, he was named Distinguished Honorary Professor by the Chinese Academy of Science (Changchun) and the Huazhong University of Science and Technology.
He has received prestigious awards including : • the RUSNANO Prize, Dr. Honoris • the Balzan Prize • the Galvani medal • the Harvey Prize • the Faraday Medal, • the Gerischer Award • the Dutch Havinga Award and Medal • the International Prize of the Japanese Society of Coordinaton Chemistry • the ENI-Italgas Energy-Prize and the year 2000 European Grand Prix of Innovation. |
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About his interest and research:
The main focus of research is to generate electric power or fuels from sunlight. The inverse process of producing light from electricity in organic light emitting diodes (OLEDS) is also being investigated. The great majority of devices examined in our laboratories employs mesoscopic structures composed of nano sized particles as a key substrate element. In fact, it was the Graetzel group at LPI that pioneered the use of such mesoscopic architectures for the solar production of electricity and fuels. The choice of mesoscopic oxides is supported by our extensive studies of photo induced electron- and energy-transfer processes of nanocrystalline systems of various kinds. The advantages of mesoscopic oxide substrates are manifold. Advances in the understanding on how to control/manipulate interfacial charge transfer enables to design efficient photo chemical systems that effect overall conversion of solar energy as electric power as in solar cells or as solar fuels such as H2 from photoelectrochemical water splitting and reduction of CO2 to methanol and other C1 products.
Projects
Dye sensitized solar cells (DSSCs) are curently produced by industry and sold commercially on the megawatt scale as light-weight flexible cells for powering portable electronic devices and as electricity producing glass panels for application in building integrated photovoltaics. The DSSC has engendered perovskite solar cells (PSCs) that have revolutionized the whole field of photovoltaics reaching over 22% efficiency only a few years after their inception. This exceeds the performance of polycrystalline silicon solar cells.
The goal of the below projects is to enhance the industrial development of sensitized solar cells on a large scale. There are at least two applications where DSCs offers unique selling propositions: i) flexible light weight embodiments to supply electric power in particular for portable electronic devices and ii) Look through electricity glass panels for BIPV. Commercial sales of dye-sensitized solar cells have started in these two markets and some examples are shown in the figures below.
i) The conception and synthesis of a new class of sensitizers that achieve high device performance and durability while responding at the same time to the strong market demand for DSSC glass panels for specific colors in particular green and blue. These sensitizers will be used in BIPV end products, which will be marketed by g2e for glazing and building façade applications. In addition to ruthenium complexes, organic donor acceptor dyes will be explored in this direction. We shall develop new routes for preparing an intensely blue organic dye whose synthesis can be upscaled to the 100 kg quantities at a cost of < 100 CHF/g. We shall also endow the currently used green porphyrin dye with stronger anchoring groups and simplify their synthesis. Further more we shall design and synthesize highly stable novel organic sensitizers, which response in the visible and near IR regions having absorption coefficients of over 100,000 M-1 cm-1.The target sensitizers are phthalocyanines and novel donor- chromophore-acceptor organic dyes
ii) The development of novel ionic liquid electrolytes (ILE) that achieve high solar to electric power conversion efficiencies (PCEs) for currently used formulations while offering the high stability and transparency required for applications of DSSC glass panels in the building industry. Alternate new ionic liquids are selected from the collaborative work with Lonza and Merck companies and the electrolyte compositions will be formulated to achieve targeted high device performances. The synthesis of these new ionic liquids is cheaper than the state of the art ionic liquid. New solid state formulations employing gel forming agents and inorganic nano-composites will be realized that ascertain excellent prospects for large scale applications and will accelerate market penetration of the electric power generating glass panels produced by industrial partners.
iii) The development of new nanostructured titania films, whose pore size, shape and porosity will be engineered to sustain photocurrent densities of up to 20 mA/cm2 without suffering mass transport limitations when used in conjunction with the new ionic liquid electrolytes. This is a necessary condition to meet the ambitious efficiency goals set for ionic liquids.
iv) Development of perovskite solar cells (PVCs). LPI maintains a leading position in the field metal halide perovskite solar cells whose meteoric rise in efficiency to a current certified level of 17.9% has stunned the PV community. A major thrust of our current research is dedicated to exploit the full strength of these low cost and solution processed photovoltaics which have the potential to reach or even surpass power conversion efficiencies of 20%. Nevertheless, this technology is still in its infancy and there remain major challenges such as ascertaining long time stability under outdoor conditions, which we shall address. (M.Grätzel Nature Materials 2014, 13, 838).
Impacts
These goals will be reached through introducing revolutionary new concepts in the choice of the three materials that play a key role for their performance and durability of the DSSC, i.e., the light haresting pigment, the electrolyte or hole conductor and the mesoporous TiO2 scaffold. His research output will pave the way to enhance the production and sales of a new generation of durable and highly efficient glass panels that meet the esthetic and high quality demand of the market.
Publication list
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