Stéphane Jobic (DR), Hélène Serier-Brault (MC), Philippe Deniard (DR), Emmanuel Fritsch (Pr), Martine Bujoli-Doeuff (MC), Laurence Ourry (Postdoc).
An X-chromic material is a material which color changes under the action of an external stimulus such as temperature, pressure or light excitation. Thermochomism and tribochromism (or piezochromism) often go hand in hand. If the temperature is raised up, the material will expand, if the material undergoes a pressure, it will contract. In both cases, the two stimuli will modify the interatomic distances and thus trigger a reorganization of the electronic cloud within the material. Then, a continuous color change is expected in relation with a regular modification of the electronic transitions in energy. Temperature and pressure can also lead to a so-called first order transition with the appearance of a new structural type for a given value of the stimulus. The color change can then be abrupt. Namely, our goal is to understand the origin of the color in the synthesized materials at the laboratory and to predict as much as possible the color characteristics of solid materials in a given temperature or pressure range. Thermochromic effects may also be observed in composites not described herein.
In parallel with thermochromism and tribochromism, we are interested by photochromism. This phenomenon can be observed in hybrid materials constructed on a supramolecular assembly of polyoxomolybdates and organoammonium cations (see section "Hybrid photoactivable materials" (web link)), but also in inorganic materials. In this context, we have been investigation compounds of the family of sodalites which exhibit photochromic behavior under UV excitation with a quasi-instantaneous discoloration under the effect of a blue flash light. Such materials could ultimately have applications in the field of optical storage.
|Change from red to green by heating and from green to red by cooling (or simply pressing the finger at room temperature) of the material CuMo0.9W0.1O4|
|Continuous evolution from green to red of a garnet iron yttrium|
|Evolution of the color of a sodalite cabochon subjected to daylight, to irradiation at 365 nm and to a "blue" flash.|
Current: Stéphane Jobic (DR), Hélène Serier-Brault (MC), Philippe Deniard (DR), Emmanuel Fritsch (Pr), Martine Bujoli-Doeuff (MC), Laurence Ourry (Postdoc)
Past: Manuel Gaudon
Unprecedented "one finger push" induced phase transition with a drastic color change in an inorganic material
M. Gaudon, S. Jobic, A. Demourgues, P. Deniard, A-E. Thiry, C. Carbonera, A. Le Nestour, A. Largeteau, J-F Létard
Adv. Mater., 19, 3517-3519, 2007
Adaptable thermochromism in the CuMo1-xWxO4 series (0 £ x < 0.1): a behavior related to a first order phase transition with a transition temperature depending on x
M. Gaudon, C. Carbonera, A.E. Thiry, A. Demourgues, P. Deniard, C. Payen, J-F. Létard, S. Jobic
Inorg. Chem., 46, 10200-10207, 2007
On the cyclability of the thermochromism in CuMoO4 and CuMo0.9W0.1O4
A.-E. Thiry, M. Gaudon, C. Payen, P. Deniard, X. Rocquefelte, A. Demourgues, M.-H. Whangbo, S. Jobic
Chem. Mater., 20, 2075-2077, 2008
How to mimic the thermo-induced red to green transition of ruby with control of the temperature via the use of an organic materials blend?
M. Gaudon, P. Deniard, L. Voisin, G. Lacombe, F. Darnat, A. Demourgues, J-L. Périllon, S. Jobic
Dyes and Pigments, 95, 344-350, 2012
Thermochromism in Yttrium Iron Garnet Compounds
H. Serier-Brault, L. Thibault, M. Legrain, P. Deniard, X. Rocquefelte, P. Leone, J-L. Perillon, S. Le Bris, J. Waku, S. Jobic
Inorganic Chemistry, 53(23), 12378-12383 (2014).
Institut de Chimie de la Matière Condensée de Bordeaux
ANR and contracts
Contrats industriels avec l'entreprise Seb-Tefal