# Michael Grätzel
**Michael Grätzel** (born 1944 in Dorfchemnitz, Germany) is a Swiss chemist and professor of physical chemistry at the [École Polytechnique Fédérale de Lausanne](https://www.edgepedia.org/ecole-polytechnique-federale-de-lausanne) (EPFL) who directs the Laboratory of Photonics and Interfaces and is best known as co-inventor of the dye-sensitized solar cell, the photovoltaic device that bears his name as the Grätzel cell.[1](https://www.balzan.org/en/prizewinners/michael-gratzel/bio-bibliography) • [2](https://actu.epfl.ch/news/gratzel-solar-cells-achieve-a-new-record/) He received the 2009 Balzan Prize and the 2010 [Millennium Technology Prize](https://www.edgepedia.org/millennium-technology-prize) for this work, and his research group later drove the rise of perovskite solar cells, for which EPFL's June 2021 research summary reported a certified 25.5% efficiency for multi-cation solution-processed cells.[3](https://www.balzan.org/en/prizewinners/michael-gratzel) • [4](https://millenniumprize.org/winners/dye-sensitised-solar-cells/) • [5](https://www.epfl.ch/labs/lpi/wp-content/uploads/2021/06/M_Grtzel-research-achievements-and-their-social-economic-impact-June-2021.pdf)
| Key fact | Detail |
|---|---|
| Born | 1944, Dorfchemnitz (Germany); Swiss citizen[1](https://www.balzan.org/en/prizewinners/michael-gratzel/bio-bibliography) |
| Signature work | O'Regan & Grätzel, "A low-cost, high efficiency solar cell based on dye-sensitized colloidal TiO2 films", Nature 353, 737–740 (1991)[6](https://www.nature.com/articles/35104607) |
| DSC efficiency | Close to 15% in full sunlight and over 35% in ambient light per EPFL; independent reviews put laboratory records at about 14%[7](https://www.epfl.ch/labs/lpi/graetzel/) • [8](https://link.springer.com/article/10.1007/s44371-026-00548-1) |
| Perovskite efficiency | EPFL's June 2021 research summary reported a certified 25.5% for multi-cation solution-processed perovskite cells, exceeding polycrystalline silicon[5](https://www.epfl.ch/labs/lpi/wp-content/uploads/2021/06/M_Grtzel-research-achievements-and-their-social-economic-impact-June-2021.pdf) |
| Prizes | 2009 Balzan Prize for the Science of New Materials; 2010 Millennium Technology Prize[3](https://www.balzan.org/en/prizewinners/michael-gratzel) • [4](https://millenniumprize.org/winners/dye-sensitised-solar-cells/) |
| EPFL role | Associate Professor 1977–1981, full Professor of Physical Chemistry since 1981, directing the Laboratory of Photonics and Interfaces[1](https://www.balzan.org/en/prizewinners/michael-gratzel/bio-bibliography) |
## Life and career
Grätzel studied chemistry at the [Free University of Berlin](https://www.edgepedia.org/free-university-of-berlin), graduating in 1968, and took his doctorate in physical chemistry at the Technical University of Berlin in 1971, summa cum laude; he habilitated in physical chemistry in 1976.[1](https://www.balzan.org/en/prizewinners/michael-gratzel/bio-bibliography) • [7](https://www.epfl.ch/labs/lpi/graetzel/) In 1977 he moved to the [École Polytechnique](https://www.edgepedia.org/ecole-polytechnique) de Lausanne as an associate professor and has been full professor of physical chemistry there since 1981.[1](https://www.balzan.org/en/prizewinners/michael-gratzel/bio-bibliography) He headed EPFL's chemistry department from 1983 to 1985 and again from 1991 to 1993.[1](https://www.balzan.org/en/prizewinners/michael-gratzel/bio-bibliography)
## The dye-sensitized solar cell
A dye-sensitized solar cell (DSC or DSSC) is a photoelectrochemical device in which a photosensitive dye attached to a mesoporous (material riddled with nanoscale pores) semiconductor oxide, usually titanium dioxide, absorbs sunlight and injects electrons into the oxide's conduction band; the electrons percolate through the mesoporous film to a collector electrode, and a redox electrolyte regenerates the dye, closing the circuit.[2](https://actu.epfl.ch/news/gratzel-solar-cells-achieve-a-new-record/) • [9](https://pubs.acs.org/doi/10.1021/ic0508371) • [8](https://link.springer.com/article/10.1007/s44371-026-00548-1) Unlike a conventional planar p-n junction, the DSC separates light absorption from charge carrier transport, which EPFL describes as mimicking the light reaction of natural photosynthesis.[7](https://www.epfl.ch/labs/lpi/graetzel/)
**The mesoporous breakthrough.** The key discovery was mesoporous TiO2 films with a roughness factor of roughly 1,000, meaning the internal surface area is about a thousand times the geometric area of the film.[10](https://pmc.ncbi.nlm.nih.gov/articles/PMC6261913/) Grätzel has stated that going from planar devices to three-dimensional junctions increased the photoconversion efficiency by a factor of 10,000, because a monolayer of dye on such a nanostructured surface absorbs far more light than on a flat electrode.[11](https://doi.org/10.1021/acsenergylett.7b00523) The prototype cell is thus a three-dimensional interpenetrating network of dye-coated nanocrystals, electrolyte, and collector, in contrast to the planar architecture of silicon cells.[7](https://www.epfl.ch/labs/lpi/graetzel/)
The cell was co-invented by Brian O'Regan and Michael Grätzel; one review dates the original co-invention to 1988 at UC Berkeley, with the 7%-efficient cell published in 1991, while other accounts date the invention to the 1991 Nature paper itself.[10](https://pmc.ncbi.nlm.nih.gov/articles/PMC6261913/) • [2](https://actu.epfl.ch/news/gratzel-solar-cells-achieve-a-new-record/) The landmark paper, "A low-cost, high efficiency solar cell based on dye-sensitized colloidal TiO2 films", appeared in Nature volume 353, pages 737–740, in 1991.[6](https://www.nature.com/articles/35104607) Nanocrystalline DSCs have reached 10.6% solar-to-current conversion under standard AM 1.5 sunlight.[12](https://www.sciencedirect.com/science/article/abs/pii/S101060300400108X)
## Perovskite solar cells and later research
The perovskite photovoltaic line grew directly out of the DSC. In 2009 [Tsutomu Miyasaka](https://www.edgepedia.org/tsutomu-miyasaka)'s group applied MAPbI3 nanoparticles in liquid dye-sensitized cells at 3% efficiency with poor stability; in 2012 solid-state versions were announced by the groups of Kanatzidis, Miyasaka/Snaith, and Grätzel/Park, showing dramatically improved stability and about 10% efficiency.[5](https://www.epfl.ch/labs/lpi/wp-content/uploads/2021/06/M_Grtzel-research-achievements-and-their-social-economic-impact-June-2021.pdf) Within a year Grätzel raised the efficiency from 10% to 15% using sequential deposition, and his group was the first to reach a certified efficiency above 21% with multi-cation formulations that stabilize FAPbI3 by adding methylammonium or cesium.[5](https://www.epfl.ch/labs/lpi/wp-content/uploads/2021/06/M_Grtzel-research-achievements-and-their-social-economic-impact-June-2021.pdf)
The field's growth has been rapid: perovskite cells reached 25.65% solar-to-electric efficiency in 2020, with close to 20,000 papers published on the subject over the preceding eight years.[7](https://www.epfl.ch/labs/lpi/graetzel/) Beyond single-junction cells, EPFL and CSEM achieved an independently certified 30.02% efficiency for a perovskite-perovskite-silicon triple-junction cell, surpassing the previous certified record of 27.1%.[13](https://actu.epfl.ch/news/record-efficiency-for-perovskite-silicon-triple-ju/)
## By the numbers
Efficiency figures for DSCs differ by source and should be attributed carefully. EPFL's lab page reports close to 15% in full sunlight and over 35% in ambient light; an EPFL news release describes a certified 15.2% under standard simulated sunlight with 500-hour stability, and 28.4% to 30.2% over ambient light intensities at a 2.8 cm² active area.[7](https://www.epfl.ch/labs/lpi/graetzel/) • [2](https://actu.epfl.ch/news/gratzel-solar-cells-achieve-a-new-record/) A 2026 systematic review states that laboratory-scale DSC records have leveled off at about 14%, and a 2019 dye review notes that the highest DSSC efficiency officially recognized by the [National Renewable Energy Laboratory](https://www.edgepedia.org/national-renewable-energy-laboratory) remained about 11.9% from 2013 onward.[8](https://link.springer.com/article/10.1007/s44371-026-00548-1) • [14](https://www.e-asct.org/journal/view.html?doi=10.5757%2FASCT.2019.28.6.194)
Grätzel's bibliometrics are also reported differently on two EPFL pages: the lab page gives 1,650 publications, about 325,000 citations, and an h-index of 259 ([Web of Science](https://www.edgepedia.org/web-of-science), May 2021), and adds that a Stanford University ranking placed him first among 100,000 top scientists across all fields.[7](https://www.epfl.ch/labs/lpi/graetzel/)
## How it compares with other solar technologies
On full-sunlight efficiency, DSCs trail the mature technologies: the 2026 review puts commercial silicon at 27.03% and perovskite solar cells at 26.70%, against DSC laboratory records of about 14%.[8](https://link.springer.com/article/10.1007/s44371-026-00548-1) Where the DSC wins is ambient and diffuse light: EPFL reports over 35% conversion at indoor light levels, which suits battery-replacement applications in consumer electronics, and the cells can be made as semitransparent glass panels and flexible modules.[7](https://www.epfl.ch/labs/lpi/graetzel/) • [2](https://actu.epfl.ch/news/gratzel-solar-cells-achieve-a-new-record/) [Perovskite](https://www.edgepedia.org/perovskite) cells, by contrast, compete directly with silicon on efficiency; EPFL's research summary states that the certified 25.5% of multi-cation solution-processed cells exceeds [polycrystalline silicon](https://www.edgepedia.org/polycrystalline-silicon), with projected levelized cost of electricity 2 to 3 times cheaper.[5](https://www.epfl.ch/labs/lpi/wp-content/uploads/2021/06/M_Grtzel-research-achievements-and-their-social-economic-impact-June-2021.pdf)
## Honors and recognition
The Balzan Foundation awarded Grätzel the 2009 Balzan Prize for the Science of New Materials for inventing a whole new class of solar cells in which dye molecules capture sunlight and release electrons to a nanocrystal network; its bio-bibliography cites the invention and development of the dye-sensitized cell, commonly known as the Grätzel cell.[3](https://www.balzan.org/en/prizewinners/michael-gratzel) • [1](https://www.balzan.org/en/prizewinners/michael-gratzel/bio-bibliography) In 2010 he received the Millennium Technology Prize, described by the prize's foundation as the father of third-generation dye-sensitized solar cells, a technology often called artificial photosynthesis, made of low-cost materials and not requiring an elaborate apparatus to manufacture.[4](https://millenniumprize.org/winners/dye-sensitised-solar-cells/)
## References
1. [Michael Grätzel, Bio-bibliography, Fondazione Internazionale Premio Balzan](https://www.balzan.org/en/prizewinners/michael-gratzel/bio-bibliography)
2. ["Grätzel" solar cells achieve a new record, EPFL News](https://actu.epfl.ch/news/gratzel-solar-cells-achieve-a-new-record/)
3. [Michael Grätzel: 2009 Balzan Prize for the Science of New Materials](https://www.balzan.org/en/prizewinners/michael-gratzel)
4. [Dye-sensitised solar cells, Millennium Technology Prize](https://millenniumprize.org/winners/dye-sensitised-solar-cells/)
5. [Michael Graetzel's Research Achievements and their Social Economic Impact, EPFL LPI (June 2021)](https://www.epfl.ch/labs/lpi/wp-content/uploads/2021/06/M_Grtzel-research-achievements-and-their-social-economic-impact-June-2021.pdf)
6. [O'Regan & Grätzel (1991), Nature 353, 737–740](https://www.nature.com/articles/35104607)
7. [Prof. Michael Graetzel, Laboratory of Photonics and Interfaces, EPFL](https://www.epfl.ch/labs/lpi/graetzel/)
8. [Dye-sensitized solar cells: a systematic review of progress, challenges, and future perspectives, Springer](https://link.springer.com/article/10.1007/s44371-026-00548-1)
9. [Solar Energy Conversion by Dye-Sensitized Photovoltaic Cells, Inorganic Chemistry (ACS)](https://pubs.acs.org/doi/10.1021/ic0508371)
10. [Dye-Sensitized Solar Cells: Fundamentals and Current Status (PMC)](https://pmc.ncbi.nlm.nih.gov/articles/PMC6261913/)
11. [A Conversation with Michael Grätzel, Exa](https://doi.org/10.1021/acsenergylett.7b00523)
12. [Conversion of sunlight to electric power by nanocrystalline dye-sensitized solar cells, ScienceDirect](https://www.sciencedirect.com/science/article/abs/pii/S101060300400108X)
13. [Record efficiency for perovskite-silicon triple-junction solar cells, EPFL News](https://actu.epfl.ch/news/record-efficiency-for-perovskite-silicon-triple-ju/)
14. [Review of the Development of Dyes for Dye-Sensitized Solar Cells, Applied Science and Convergence Technology](https://www.e-asct.org/journal/view.html?doi=10.5757%2FASCT.2019.28.6.194)
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*Topic: Encyclopedia › Physical world and mathematics › Physical and mathematical scientists › Chemists › Photochemists*
*Initially written Oct 10, 2026 · Edited: Oct 11, 2026; Oct 12, 2026; Oct 15, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license