Scientific activities

Team "Chemistry and Photonic of Oxide and Fluoride Materials"

 

 

 

 

 

 


Fundamentals, chemical bonding

Pigments : Well-suited synthesis route to control particles size are investigated, while defined compositions (transition metals/rare earth) with peculiar crystal network and metal local environment are targeted. Objectives are to design red-green-blue or yellow-cyan-magenta inorganic pigments by controlling electronic transitions in optical absorption spectra (complex index: n+ik).

 

UV-IR absorbers : Here we seek to control Charge Transfer Band gap and refractive index in Ce-based, Ti-based oxides and in oxy-fluoride compounds to design materials with UV-shielding. We investigate plasmon effect in NIR region in Zn-based and In-based oxides, and oxyfluorides used as NIR absorbers and Transparent Conductive Oxides and Oxyfluorides.

 

Phosphors : Innovative phosphors-based chemical compositions are synthesized with requirement such as higher efficiency, less energy consuming, better colorimetric parameters.

 

 

Glass : We investigate the relationship between composition, structure and linear and nonlinear optical properties of glasses. Role of dopants and structures on the photosensitivity is considered.

 

 

 


Composition design and sustainability

Bi-stable compounds : Chemical compositions are tailored to obtain interesting colorimetric contrasts under pressure, temperature or current in order to monitor the environment. Typically, solid state phase order transition implied in the X-chromic mechanism is tuned and adequately characterized from various spectroscopies (DSC, Magnetism, transport measurements, in situ absorption and emission optical properties).

 

Redox properties : We investigate transition metal and rare earth-based oxides and oxy(hydroxy)fluorides with high surface area used as redox or Lewis acid/base catalysts.

 

 

Ionic mobility : Design of crystalline compounds (alkaline, transition metal, rare earth-based oxides/fluorides…) and of inorganic glasses is investigated to favor anions (O2-, F) or cations (Na+..) mobility. The objective is to improve/create ionic conductivity, reactivity in heterogeneous catalysis and second-order nonlinear optical properties.

 

Low phonons compounds : Heavy metal oxide glasses (germanate, gallate…) are investigated to enlarge their optical window in the infrared. New original glass compositions and phase diagrams, local structures, and optical properties are investigated (ex: fluorides/oxyfluorides oxide glasses and glass ceramics).

 

 


2D Functionalization

Field assisted modification of glass surface : Electric field (high voltage applied) or thermal poling can bring 2D functionality on glass surface by modifying the structure and the local composition. It gives access to innovative surface reactivity, optical and mechanical properties changes.

 

Electrophoretic and X-chromic layers  :  Here we investigate the introduction of pigments or X-chromic compounds inside adequate matrices for inks/varnishes/glassy layers preparation. We aim to develop electrophoretic inks for displays (e-books), piezochromic compounds in hybrid organo-metallic matrices (sol-gel) or photochromic oxides into Ta2O5 glass matrix (sol-gel).

 

 


3D Functionalization

3D printing of inorganic ceramic and glass : 3D printing of biomaterials is based on the synthesis of transition-metals-doped hydroxyapatites (Cu-doped, Fe-doped). Selective laser sintering is combined with fundamental studies of the light-matter interaction (temperature gradients, sintering process…) to achieve shaping as ceramic, thin or thick films. We consider also the development of adapted glass compositions for additive manufacturing or laser-assisted 3D printing.

 

Laser writing : We investigate 1D/2D/3D high optical contrast genetation using femtosecond laser direct writing in bulk and surface for integrated photonic component (waveguides, Bragg grating …) in the visible and near/mid-IR range in bulk or fibers. Femtosecond laser structuring of vitreous materials of linear and second/third-order nonlinear optical properties are investigated for creation of multi-scale nonlinear architectures for quasi-phased matched interactions or nonlinear chiral-like light/matter interaction in laser for instance.

 

Amplifying medium  : Original compositions of rare earth doped inorganic materials are developed and shaped into fibers or crystalline optical ceramics to generate gain in the near- and mid-infrared range. Applications are found in medical care, telecommunication or detection of pollutants.

 

 


Optical fibers

Infrared optical fibers : Optical fibers with exotic inorganic glass compositions (phosphates, tellurites, germanates, gallates, oxyfluorides …) are developed for optics, photonics and lasers. Applications span mainly in the infrared, covering the fields of health, telecommunications, defense.

 

Composite, hybrid and multimaterials fibers : Fibers associating new combinations of materials, new geometries or new fabrication protocols are developed. An example is given by fibers made of polymers, glasses and metals. The incorporation of materials with disparate properties is expected to extend fiber functionalities in endoscopy, detection or even flexible electronics.