ICMCB-CNRS-University of Bordeaux ,France
42 years-old, University of Bordeaux associate professor-HDR, over 70 publications in international journals. She is a specialist of luminescence of inorganic doped compounds. V. Jubera has been working as an associate professor at the ICMCB-CNRS, University of Bordeaux for 14 years. Her research topic deals with the structure-luminescence properties of crystallized materials. The luminescence spectroscopy is performed to evaluate the potentiality of phosphors for displays, lighting, sensing or lasers materials. She has been developing in the Institute, topics on the synthesis and characterization of massive (single crystals, transparent ceramics) innovative compounds as well as nano-powders. Her activities is fully included and supported by the competitiveness cluster ”Routes des Lasers” and the cluster Laphia (IDEX Univ. de Bordeaux).
Considerable efforts have been carried out to develop new tools and research efforts in the domain of functionalized materials (information, lighting, communication, energy etc). As an illustration, to correlate the optical response of a material to another of its property is possible through the monitoring of the luminescence.
(i) Modifications of the doping element local environment is associated to crystal field strength modification. For instance, divalent manganese radiative transitions can be observed from the green to the red ranges. Synthesis control route makes possible a red to green luminescence switch of manganese doped spinel treated at high temperature in relation with the cation migration through the host lattice. In other matrices, external factors induce unit cell symmetry transition. This effect can also be observed in rare earth doped compounds as Eu3+ doped sesquioxyde .
(ii) Irradiation energy is also an efficiency factor which can initiate redox processus. The oxidation of europium +II to europium +III state results in a shift from blue to red emission. UV irradiation of cerium doped Indium elpasolite matrix leads to the decrease of the doping element emission in favor of a bright orange emission. The corresponding redox process is reversible under adequate irradiation or heat treatment temperature. Such local modification can easily be detected over the visible range.
(iii) Emission of ZnO are strongly related to synthetic routes. Low operating temperature can result in the appearing of surface and bulk defects. Their existence impacts not only the emission wavelength but also its stability under specific atmosphere.
Finally, luminescence spectroscopy is not only a technique to register the spectral distribution of the excitation or emission radiative de-excitation, it is also an efficient tool to highlight the influence of external factors and to record the history of a materials.