Soutenance de Thèse d'Elisabeth PAYRER - Light up–conversion in rare earth doped thin films: synthesis, characterization, luminescence and prospects for solar cell application

Photon up-conversion (UpC) allows the generation of light of shorter wavelengths compared to the excitation wavelength. In this work the synthesis of thin films doped with optically active rare earth ions, their structural characterization, as well the optical and photoluminescence properties are highlighted. The emphasis lies on two different routes of film deposition on Si and transparent substrates: first, MOCVD (LI-MOCVD, AA-MOCVD) is introduced for the deposition of Er/Yb-doped YF3 and Y2O3 films and it is demonstrated, how the NIR-to-Vis UpC emission of Er3+ is influenced by the host lattice. Secondly, sol-gel processing is used for the fabrication of Er/Yb-doped Y2O3, SiO2 and TiO2 thin films by spin-coating. Moreover, sol-gel derived Fabry-Pérot microcavities, consisting of a multilayer stack of SiO2 and TiO2 layers and Er/Yb:Y2O3 as the cavity layer, are investigated to influence the UpC emission.

The following questions are addressed: how does the nature of the host lattice and doping level influence the radiative emission in Er3+, what are the requirements for a good upconverter material and what are the limitations ?

Membres du jury