Directory

CNRS Research Fellow

Current functions Currently:

Since 2013: CNRS Research Scientist

Functions precedents / Before:

• 2010-2013: Postdoctoral Fellow / Northwestern University (USA)
• 2007-2010: PhD / University of Rennes (France)

Ressources en ligne – Online resources:

• ResearcherID : E-2532-2012
• ResearchGate: https://www.researchgate.net/profile/Romain_Gautier2
• Google Scholar : https://scholar.google.fr/citations?user=BiIoyN0AAAAJ&hl=en

Senior Lecturer

University Professor

Functions :

• University Professor (Section 33 Chemistry of Materials), Chemistry Department, Faculty of Science and Technology, Nantes University
• Scientific referent for the X-ray Diffraction platform of IMN’s PLASSMAT platform

Qualifications :

• HDR in Chemistry and Chemistry-Physics (University of Rennes 1) 2012: “Contribution à l’étude des phénomènes structuraux de mise en ordre/désordre par diffusion/diffraction sur grands instruments: des composés moléculaires aux oxydes des métaux de transition” (Contribution to the study of structural ordering/disordering phenomena by scattering/diffraction on large instruments: from molecular compounds to transition metal oxides).
• Doctoral thesis in Materials Science (Université Paris VI Pierre et Marie Curie, Laboratoire Léon Brillouin, UMR 12 CEA/CNRS, CEA/Saclay) 1997: “Etude par diffusion des neutrons du chlorure de bétaïne et de calcium dihydraté sous champ externe appliqué (température, champ électrique, pression hydrostatique)”.
• DEA in Materials Science (Université Paris VI Pierre et Marie Curie) 1993
• Master’s degree in Physics (Université du Maine, Le Mans) 1992

Expertises :

• Ab initio structural resolution on powder and single crystal by XRD
• Structural, Rietveld, sequential or parametric refinements
• Study of static and dynamic disorder using the maximum entropy method (MEM) and anharmonic development of atomic displacement parameters
• TLS analysis of atomic displacement parameters
• Determination of mottled or stacking fault crystal structures
• Determining modulated incommensurate or composite incommensurate crystal structures (misfits): the superspace approach
• Pair distribution function (PDF) analysis coupled with total X-ray and neutron scattering
• Microstructural diffraction analysis
• In situ or operando diffraction
• Determination of magnetic structures by neutron diffraction
• Studies of structural or magnetic phase transitions
• Crystallochemistry of chalcogenides (including oxides) and transition metal clusters

Main research themes:

• Advanced solid-state crystallography (by X-ray, neutron and electron diffraction/diffusion): transition metal chalcogenides, polyoxometallates and organic-inorganic transition element hybrid compounds
• Chemical and electrochemical reactivity, crystallochemical, magnetic and ionic diffusion properties in oxides, mixed anion compounds and transition metal clusters
• Ordering/disordering phenomena in solids
• Advanced crystallographic approaches

Current research projects :

• Layered polychalcogenides (S. Sasaki/L. Cario, ANR COBEDIT)
• Thermoelectric sulfide misfits (D. Berthebaud/S. Jobic/L. Cario)
• Superconducting selenide misfits (L. Cario/S. Sasaki, ANR MISFIT)
• Layered oxychalcogenides with stacking faults (S. Sasaki)
• Luminescent polyoxometallates for water detection (R. Dessapt, Y. Cartigny, ANR ALPS-Water)
• AI-assisted methodology for the discovery of new materials in molten salt (R. Gautier/D. Berthebaud/D. Portehault (LCMCP), MADNESS PEPR DIADEM)
• Mechanochromic luminescence in copper iodide clusters (S. Perruchas)
• Hybrid perosvskites for thermal storage (T. Devic)
• Metal clusters and proton conducting polyoxometallates (S. Cordier (ISCR Rennes), C. Falaise (ILV Versailles), J. Cuny (LCPQ Toulouse), ANR PRESTO submitted)
• Mixed-anion Mo cluster nanoribbons (ISCR Rennes, Institut Josef Stefan, Slovenia)
• Perovskite-derived oxides for SOFC and SOEC applications: defects and diffusion paths (J. Gamon, J.-M. Bassat, ICMCB Bordeaux)
• Lacunar layered perovskites (Kyoto University: H. Kagayama & K. Fujita’s laboratories)

Activities in the research community :

• Member of the CNRS RECIPROCS network (Network of researchers and ITA professionals in structural crystallography)
• Member of the scientific committee for the Association Française de Cristallographie congress in 2026

Biography:

After my PhD thesis in Materials Science (1994-1997: Université Paris VI Pierre & Marie Curie; Laboratoire Léon Brillouin, CEA/Saclay), I spent two post-doctoral years as a contract teacher-researcher: ATER at Université Paris VI Pierre & Marie Curie in 1997-1998 (Laboratoire Léon Brillouin) then ATER at Université de Lille 1 in 1998-1999 (Laboratoire de Dynamique et Structure des Matériaux Moléculaires, UMR CNRS 8024, currently Unité Matériaux et Transformations, UMR CNRS 8207). I was appointed Maître de Conférences des Universités in Section 33 Chemistry of Materials at the University of Rennes 1 in September 1999, in the Structure and Properties of Matter Department. From 1999 to 2006, I was based at the Laboratoire de Chimie du Solide et Inorganique Moléculaire (UMR CNRS 6511), and from 2006 to August 2022 I carried out my research activities at the ISCR (UMR CNRS 6226) in the Inorganic Materials: Soft Chemistry and Reactivity and Solid Chemistry and Materials teams. In 2004-2005, a CRCT allowed me to spend 8 months in the Crystalography Laboratory at EPFL in Switzerland. In September 2022, I was recruited to the Chemistry Department of the Faculty of Science and Technology at Nantes University, within the IMN MIOPS team, following a competitive examination for the 46-1 position of University Professor (section 33 Chemistry of Materials).

Teaching :
For the Chemistry Department of the Faculty of Science and Technology of Nantes University :

• X-ray powder diffraction (M2 A3M)
• Advanced X-ray and neutron diffraction (M2 E-MAT)
• Crystallography and X-ray diffraction (M1 A3M, SdM, LUMOMAT)
• Statistical thermodynamics (L3 PC)
• Group theory (L3 PC)
• Coordination chemistry (L3 C)
• Thermochemistry (L2 C)
• Inorganic Chemistry (L1)
• Thermochemistry and equilibria in aqueous solutions (L1)

For IUT Sciences et Génie des Matériaux, Nantes Université:
Diffraction techniques (BUT3)

For the University of Rennes:
Crystallography (International Master 1 in Chemistry-M1 LUMOMAT)

IMN Level 1 short continuing education course (1 week) “Diffraction in polycrystalline materials”:
X-ray powder diffraction, Symmetry in crystals, Microstructure (external standard and fundamental parameters), Phase quantification

Publications :

Number of publications: 85

Major illustrative publications:

Mechanoresponsive luminescence triggered by phase transition of a supercooled copper(I) complex J. Delafoulhouze, M. Cordier, J.-Y. Mevellec, F. Massuyeau, O. Hernandez, C. Latouche, S. Perruchas CHEMICAL COMMUNICATIONS 60, 5278-5281 (2024)

Exsolution of Co-Fe alloy nanoparticles on the PrBaFeCoO5+ layered perovskite monitored by neutron powder diffraction and catalytic effect on dry reforming of methane P. Managutti, H. Yu, O. J. Hernandez, C. Prestipino, V. Dorcet, H. Wang, T. C. Hansen, M. Bahout ACS APPLIED MATERIALS & INTERFACES 15 (19), 23040-23050 (2023)

Mechanochemical Synthesis and Study of the Local Structure of NaGaS2 Glass and Glass-Ceramics L. Verger, J. Trébosc, B. Baptiste, E. Furet, K. Dénoue, J. Zhang, F. Cheviré, D. Le Coq, L. Calvez, O. Lafon, O. Hernandez INORGANIC CHEMISTRY 61, 46, 18476-18485 (2022)

In Situ Synchrotron Powder Diffraction Study of Cd Intercalation into Chevrel Phases: Crystal Structure and Kinetic Effect J. Barbosa, C. Prestipino, O. J. Hernandez, S. Paofai, C. Dejoie, M. Guilloux-Viry, C. Boulanger INORGANIC CHEMISTRY 58, 3, 2158-2168 (2019)

‘Hybrid Improper Ferroelectricity in (Sr,Ca)3Sn2O7 and Beyond: Universal Relationship between Ferroelectric Transition Temperature and Tolerance Factor in n = 2 Ruddlesden-Popper Phases
S. Yoshida, H. Akamatsu, R. Tsuji, O. Hernandez, H. Padmanabhan, A. Sen Gupta, A. S. Gibbs, K. Mibu, S. Murai, J. M. Rondinelli, V. Gopalan, K. Tanaka, K. Fujita JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 140, 15690-15700 (2018)

Site Selectivity of Hydride in Early-Transition-Metal Ruddlesden-Popper Oxyhydrides O. J. Hernandez, G. Geneste, T. Yajima, Y. Kobayashi, M. Okura, K. Aidzu, C. Tassel, S. Paofai, D. Swain, C. Ritter, H. Kageyama INORGANIC CHEMISTRY 57, 11058-11067 (2018)

Structure and reactivity with oxygen of Pr2NiO4+δ: an in situ synchrotron X-ray powder diffraction study T. Broux, C. Prestipino, M. Bahout, S. Paofai, E. Elkaïm, V. Vibhu, J.-C. Grenier, A. Rougier, J.- M. Bassat, O. Hernandez DALTON TRANSACTIONS 45, 3024-3033 (2016)

Hydride in BaTiO2.5H0.5: A Labile Ligand in Solid State Chemistry N. Masuda, Y. Kobayashi, O. Hernandez, T. Bataille, S. Paofai, H. Suzuki,C. Ritter, N. Ichijo, Y. Noda, K. Takegoshi, C. Tassel, T. Yamamoto, H. Kageyama JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 137, 15315-15321 (2015)

Oxygen diffusion mechanism in the mixed ion-electron conductor NdBaCo2O5+x Y Hu, O. Hernandez, T. Broux, M. Bahout, J. Hermet, A. Ottochian, C. Ritter, G. Geneste, G. Dezanneau
JOURNAL OF MATERIALS CHEMISTRY 22, 36, 18744-18747 (2012)

An oxyhydride of BaTiO3 exhibiting hydride exchange and electronic conductivity Y. Kobayashi, O.J. Hernandez, T. Sakaguchi, T. Yajima, T. Roisnel, Y. Tsujimoto, M. Morita, Y. Noda, Y. Mogami, A. Kitada, M. Ohkura, S. Hosokawa, Z.F. Li, K. Hayashi, Y. Kusano, J.E. Kim, N. Tsuji, A. Fujiwara, Y. Matsushita, K. Yoshimura, K. Takegoshi, M. Inoue, M. Takano, H. Kageyama NATURE MATERIALS 11, 6, 507-511 (2012)

Tetrahedral Mo4 Clusters as Building Blocks for the Design of Clathrate-Related Giant Frameworks M.A. Shestopalov, A.Y. Ledneva, S. Cordier, O. Hernandez, M. Potel, T. Roisnel, N.G. Naumov, C. Perrin ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 50, 32, 7300-7303 (2011)

Patent :

1 submitted (“Matériau à changement de phase solide solide pour la thermalisation et le stockage thermique”, C. Archinard, E. Djanffar, T. Devic, O. Hernandez, A. Saad, E. Zekri, G. Largiller, DV 5547 Réf. SATT Ouest Valorisation, DD25114 Réf. CEA)

CNRS Research Director

CNRS Research Director

University Professor

Senior Lecturer

Functions :

• Associate Professor in Thin-Film Photovoltaics – Institute of Materials of Nantes Jean Rouxel (IMN-UMR6502)
• Director of the Preparatory Cycle- Polytech Nantes School of Engineering

Qualifications :

• 63 – Electrical, Electronic, Photonic, and Systems Engineering
• 28 – Condensed Matter and Materials

Expertises :

• Photovoltaics
• Chalcogenide thin films coevaporation

Main research topics
Low-temperature synthesis of wide bandgap selenide absorbers for PV applications

Current research projects :

• SITA HORIZON CL5-D3-02-04
• PASTEL ANR-PRCE CE05
• SIPHON ANR-JCJC-CE05
• IOTA PEPR-TASE 22-PETA-0005 2024, ongoing
• PARACELSis M.ERA-NET

Biography:
Thomas Lepetit received his M.S. in Applied Physics from the École Normale Supérieure de Cachan in 2012 and his Ph.D. in Materials Science from the University of Nantes in 2015. His doctoral research focused on the synthesis and characterization of chalcogenide thin films for photovoltaic applications, particularly heavy alkali post-treatments applied to Cu(In,Ga)Se₂ absorbers, which enable high photovoltaic conversion efficiencies. He also explored in-situ treatments based on metal halides, which promote crystallization and support low-temperature growth.
Dr. Lepetit is currently an associate researcher at the Institut des Matériaux Jean Rouxel (IMN) and leads the preparatory cycle at Polytech Nantes, the engineering school of Nantes University, managing a cohort of approximately 350 students. He is or has been actively involved in several national (ANR-PRCE PASTEL, ANR-PEPR IOTA, ANR-JCJC SIPHON) and international (HORIZON-SITA, M-ERA.NET PARACELSis) research projects, including the co-supervision of three postdoctoral researchers and two Ph.D. candidates. He has co-authored more than 20 articles in peer reviewed journal (h-index of 12).

Teaching:
Electromagnetsim, Optics, Power electronics conversion, Multidisciplinary projects

Publications:
20 peer-reviewed publications
index: 12
i10 index: 16

• Palmiotti, E., Tsoulka, P., Poudel, D., Marsillac, S., Barreau, N., Rockett, A., & Lepetit, T. (2022). Homogeneous CuGaSe2 growth by the CuPRO process with In-Situ AgBr treatment. Thin Solid Films, 762, 139488. (https://doi.org/10.1016/j.tsf.2022.139488)
• Lepetit, T., Harel, S., Arzel, L., Ouvrard, G., & Barreau, N. (2017). KF post deposition treatment in co-evaporated Cu(In,Ga)Se2 thin film solar cells: Beneficial or detrimental effect induced by the absorber characteristics. Progress in Photovoltaics: Research and Applications, 25(12), 1068-1076. (https://doi.org/10.1002/pip.2924)
• Lepetit, T., Harel, S., Arzel, L., Ouvrard, G., & Barreau, N. (2016). Coevaporated KInSe2: a fast alternative to KF postdeposition treatment in high-efficiency Cu(In,Ga)Se2 thin film solar cells. IEEE Journal of Photovoltaics, 6(5), 1316-1320. (https://doi.org/10.1109/jphotov.2016.2589365)

Link to publi HAL: https://cv.hal.science/thomas-lepetit
Link to orcid: 0000-0003-4010-2282
Link to scholar.google.fr: https://scholar.google.com/citations?user=DkHzmC0AAAAJ&hl=fr&oi=ao

University Professor

CNRS Research Fellow

Functions :

• CNRS Research Fellow (Section 15 – Chemistry of materials, nanomaterials and processes)
• 2023-2025: Marie Skłodowska-Curie Individual Fellow (MSCA-PF)
• 2020-2023: Postdoctoral researcher with Pf. J. P. Hofmann, Pf. W. Jaegermann and Dr. T. Mayer at the Technical University of Darmstadt, Germany

Qualifications :

• 2019 : PhD thesis from the University of Lyon in Chemical Physics and Catalysis under the supervision of Dr. C. Geantet, Dr. E. Puzenat, Dr. L. Cardenas, Dr. P. Afanasiev
• 2016: Master’s degree from ENSMAC (formerly ENSCBP) and the University of Bordeaux, specializing in Chemical Physics, Materials Chemistry and Energy.

Expertises :

Photoelectron spectroscopy for solar energy conversion materials.

Main research themes:

• Thin films and nanopowders: oxides, oxynitrides, chalcogenides
• Photoelectron spectroscopy: (XPS, UPS, Synchrotron)
• Photocatalysis, Photoelectrocatalysis, Solar fuels

Current research projects :

• Coordinator of the Marie Skłodowska-Curie Individual Fellow Project (MSCA-PF) “Valence band engineering of oxidation materials for cheap and sustainable solar fuel production” (OMATSOLFUEL) (2023-2025).
• Member of the ANR “Visible-light Photocatalysis with Ambipolar layered CHAlcogenides for Solar fuel generation” (PACHAS) (2025-2029).
• Member of ANR “Bi-Based nanOmaterials for Photocatalysis” (BiBOP) (2024-2028)
• Member of ANR “Development of a membrane-cell for in situ NAP-XPS characterization” (NACELL) (2022-2027)
• Member of the MITI project “Des matériaux Moins nobles pour une cause Noble: vers le verdissement de la dépollution des Eaux à grande échelle par électro-oxydation” (DauMiNEau) (2024-2025)

Activities in the research community :

• Member of GDR CarMANano (Groupement De Recherche Caractérisation et mesures à l’échelle nanométrique)
• Responsible for the Linkedin page of the Photoemission Spectroscopy Research Federation (FR SPE)

Biography:

Clément Maheu has been a CNRS research fellow at the Institut des Matériaux de Nantes Jean Rouxel (IMN) since 2023. A specialist in materials for solar energy conversion, he designs and characterizes semiconductors (oxides, chalcogenides, oxynitrides, etc.) for the photo(electro)catalytic production of hydrogen and high value-added molecules. In particular, it has strong expertise in photoelectron spectroscopy (XPS, UPS, SXPS) to characterize the surface of these materials.

He obtained his PhD at IRCELYON, under the supervision of Drs. Afanasiev, Cardenas, Géantet and Puzenat, on TiO2-supported transition metal sulfide co-catalysts for the photoconversion of alcohols. He deepened his expertise in photoelectron spectroscopy at the Technical University of Darmstadt, with Dr. Mayer, Prof. Jaegermann and Prof. Hofmann, applying these techniques to energy materials (photovoltaics, batteries and fuel cells). Back in France, he joined IMN, first as a postdoc on a Marie Skłodowska-Curie European fellowship, then as a full professor. In 2024, he was awarded the Junior Researcher prize by the Transversal Energy Division of the Société Chimique de France. More recently, he has initiated collaborations with researchers in the humanities and social sciences to question the deployment of photo(electro)catalytic technologies and maximize their environmental and social impact.

Awards :

• Junior researcher award from the Société Chimique de France’s Transversal Energy Division
• Thesis prize from the Catalysis 2020 Division of the Société Chimique de France

Publications :

33 (as of 05/2025)

Major illustrative publications:

• C. Maheu, V. Vandalon, M. Mattinen, T. Mayer, A. A. Bol, J. P. Hofmann, p-Type Al-Doped MoS2 Nanosheet Films: Electronic and Chemical Interface Properties with Gold for Electronic Device Integration, ACS Applied Nano Materials, 2025, 8, 9669.
• V. Nikolaou, D. Romito, C. Maheu, J. Hamon, E. Gautron, F. Massuyeau, S. Jobic, F. Odobel, Dual solar-driven hydrogen evolution and alcohol oxidation with CdS quantum dot-sensitized photocatalysts prepared by the SILAR methodology, Journal of Materials Chemistry A, 2024, 12, 30885-30891.
• C. Maheu, T. Hellmann, C. Prabowo, W. Jaegermann, J. P. Hofmann, T. Mayer, Photoelectron Spectroscopy of Co-evaporated and Spin-Coated LiTFSI-Doped Spiro-OMeTAD Reveals the Interface Energetics Inside a MAPI-based Perovskite Solar Cell, J. Phys. Chem. C, 2023, 127, 43, 21351-21362.
• C. Maheu, E. Puzenat, P. Afanasiev, L. Cardenas, C. Geantet, Photocatalytic production of H2 is a multi-criteria optimization problem: case study of RuS2/TiO2, Catalysis Today, 2021, 377, 166-175.
• C. Maheu, L. Cardenas, E. Puzenat, P. Afanasiev, C. Geantet, UPS and UV Spectroscopies combined to position the energy levels of TiO2 anatase and rutile nanopowders, Physical Chemistry Chemical Physics, 2018, 20, 40, 25629-25637.

Link to publi HAL : https://hal.science/search/index/q/*/authIdHal_s/clement-maheu

Link to orcid :https://orcid.org/0000-0001-5417-5672

Link to scholar.google.fr : https://scholar.google.com/citations?user=u3bDR5MAAAAJ&hl=fror

Other links :

https://clementmaheu.wordpress.com/

https://www.linkedin.com/in/clément-maheu-a922808a

https://bsky.app/profile/maheuclement.bsky.social

https://www.researchgate.net/profile/Clement-Maheu-2

University Professor

CNRS Research Director

Function:

• CNRS researcher (CR1 section 15)
• Researcher in the group “Innovative Materials for Optical, Photovoltaics and Storage” at the Institute of Materials Jean Rouxel of Nantes (IMN).

Before

• 2005-16 : CNRS researcher in the laboratory “Physique de la Matière Condensée (PMC)” at the Ecole Polytechnique – Palaiseau, in the group of T. Gacoin.
• 2005 : Postdoctoral position at the University of Barcelona (ICMAB) in the group of Prof. C. Rovira.
• 2003-05: Postdoctoral position at Cornell University (USA) in the group of Prof. F. DiSalvo.

Qualifications:

• 2015: ‘Habilitation à Diriger des Recherches’ from Versailles St-Quentin University, speciality Inorganic Chemistry.
• 2000-03: Ph.D. of Ecole Polytechnique at Nantes and Angers Universities, speciality Molecular Materials, in the group of P. Batail.
• 2000: Master degree “Advanced Solid State Chemistry” at Nantes University.

Research themes:

• Photoluminescent molecular materials
• Stimuli-responsive materials (mechanochromism, thermochromism, vapochromism…)
• Transition metal molecular clusters
• Copper(I) coordination chemistry

Publications:

As of 1/2017:

• 54 publications in international peer-reviewed journals.
• 1 Patent.
• 20 national/international conference presentations.