Publications by Maurin Cornuz | EPFL Graph Search

Ultrafast Charge Carrier Recombination and Trapping in Hematite Photoanodes under Applied Bias

Michael Graetzel, Maurin Cornuz, Florian Le Formal, Stanley David Tilley, Xiaoyan Wang

Transient absorption spectroscopy on subpicosecond to second time scales is used to investigate photogenerated charge carrier recombination in Si-doped nanostructured hematite (alpha-Fe2O3) photoanodes as a function of applied bias. For unbiased hematite, ...

American Chemical Society2014

Back Electron-Hole Recombination in Hematite Photoanodes for Water Splitting

Michael Graetzel, Maurin Cornuz, Florian Le Formal, Stanley David Tilley

The kinetic competition between electron-hole recombination and water oxidation is a key consideration for the development of efficient photoanodes for solar driven water splitting. In this study, we employed three complementary techniques, transient absor ...

American Chemical Society2014

Identifying champion nanostructures for solar water-splitting

Michael Graetzel, Maurin Cornuz, Cécile Hébert, Scott Charles Warren, Francesco Stellacci, Kislon Voitchovsky

Charge transport in nanoparticle-based materials underlies many emerging energy-conversion technologies, yet assessing the impact of nanometre-scale structure on charge transport across micrometre-scale distances remains a challenge. Here we develop an app ...

Nature Publishing Group2013

On the Texturing and Nanostructuring of Iron Oxide Photoanodes for Solar Water Splitting

Maurin Cornuz

The world needs to think about the after fossil fuel era and while the sun baths the earth with a tremendous amount of energy, man must learn how to harvest and store it in order to dispose of a continuous supply meeting his needs. Water photo-electrolysis ...

EPFL2013

A Ga2O3 underlayer as an isomorphic template for ultrathin hematite films toward efficient photoelectrochemical water splitting

Michael Graetzel, Maurin Cornuz, Kevin Sivula, Florian Le Formal, Jérémie Minh-Châu Brillet, Nicolas Tétreault, Takashi Hisatomi

Hematite photoanodes for photoelectrochemical (PEC) water splitting are often fabricated as extremely-thin films to minimize charge recombination because of the short diffusion lengths of photoexcited carriers. However, poor crystallinity caused by structu ...

2012

Transparent, conducting Nb:SnO2 for host-guest photoelectrochemistry

Michael Graetzel, Maurin Cornuz, Takashi Hisatomi, Morgan Mertens Stefik, Nripan Mathews

Many candidate materials for photoelectrochemical water splitting will be better employed by decoupling optical absorption from carrier transport. A promising strategy is to use multiple thin absorber layers supported on transparent, conducting materials; ...

American Chemical Society (ACS)2012

TaOxNy Sputtered Photoanodes For Solar Water Splitting

Michael Graetzel, Rosendo Sanjines, Nicolas Xanthopoulos, Maurin Cornuz, Vincent Laporte, Kevin Sivula

A series of TaOxNy photoelectrodes were deposited on F:SnO2 (FTO) substrates by DC reactive sputtering at room temperature, under a mixture of Ar, N-2 and O-2. The effects of the O-2 partial pressure during deposition (Po-2) on the films crystallinity, the ...

Elsevier Science Bv2012

Highly efficient water splitting by a dual-absorber tandem cell

Michael Graetzel, Maurin Cornuz, Jun Ho Yum, Kevin Sivula, Jérémie Minh-Châu Brillet, Takashi Hisatomi

Photoelectrochemical water-splitting devices, which use solar energy to convert water into hydrogen and oxygen, have been investigated for decades. Multijunction designs are most efficient, as they can absorb enough solar energy and provide sufficient free ...

Nature Publishing Group2012

Cathodic shift in onset potential of solar oxygen evolution on hematite by 13-group oxide overlayers

Michael Graetzel, Maurin Cornuz, Kevin Sivula, Florian Le Formal, Jérémie Minh-Châu Brillet, Nicolas Tétreault, Takashi Hisatomi

The onset potential of photoelectrochemical water oxidation on ultrathin hematite was improved by up to 200 mV by the chemical bath deposition of 13-group oxides as overlayers. It is proposed that the corundum-type overlayers released lattice strain of the ...

2011

Passivating surface states on water splitting hematite photoanodes with alumina overlayers

Michael Graetzel, Maurin Cornuz, Kevin Sivula, Florian Le Formal, Nicolas Tétreault, Thomas Moehl

Hematite is a promising material for inexpensive solar energy conversion via water splitting but has been limited by the large overpotential (0.5-0.6 V) that must be applied to afford high water oxidation photocurrent. This has conventionally been addresse ...

2011

Photo-assisted electrodeposition of cobalt-phosphate (Co-Pi) catalyst on hematite photoanodes for solar water oxidation

Michael Graetzel, Maurin Cornuz, Kevin Sivula

A photo-assisted electrodeposition approach was used to deposit a cobalt-phosphate water oxidation catalyst ("Co-Pi") onto recently improved dendritic mesostructures of alpha-Fe2O3. A comparison between this approach, electrodeposition of Co-Pi, and Co2+ w ...

2011

Light-Induced Water Splitting with Hematite: Improved Nanostructure and Iridium Oxide Catalysis

Michael Graetzel, Maurin Cornuz, Kevin Sivula, Stanley David Tilley

Revved-up rust! Light-induced water splitting over iron oxide (hematite) has been achieved by using a particle-assisted deposition technique and IrO2-based surface catalysis. Photocurrents in excess of 3 mA cm-2 were obtained at +1.23 V versus the reversib ...

Wiley-VCH Verlag GmbH2010

Examining architectures of photoanode-photovoltaic tandem cells for solar water splitting

Michael Graetzel, Maurin Cornuz, Jun Ho Yum, Kevin Sivula, Florian Le Formal, Jérémie Minh-Châu Brillet

Given the limitations of the materials available for photoelectrochemical water splitting, a multiphoton (tandem) approach is required to convert solar energy into hydrogen efficiently and durably. Here we investigate a promising system consisting of a hem ...

Cambridge University Press2010

Preferential Orientation in Hematite Films for Solar Hydrogen Production via Water Splitting

Michael Graetzel, Maurin Cornuz, Kevin Sivula

The state-of-the-art performance, obtained through the reduction of precursor gas residence time in hematite photoanodes produced by APCVD, is explained in this report by an enhanced preferential orientation of the highly conductive crystal planes perpendi ...

2010