Kathriin Utt will defend her doctoral thesis titled "Metal oxide mesostructures for optical applications" on 28 April 2016 at 14.15 at W. Ostwaldi 1, room B103.
Ilmo Sildos (PhD), TÜ Füüsika Instituut
Sven Lange (PhD), TÜ Füüsika Instituut
Tanel Tätte (PhD), TÜ Füüsika Instituut
Oponent: Krisjanis Smits (PhD), University of Latvia, Riga
Summary: This PhD thesis is aimed at using sol-gel technique for forming a variety of metal oxide structures (mostly based on ZrO2) and thorough characterization of the obtained materials. The focus is on the following applied aspects: (a) controlled morphology for better functionality, (b) phase composition and its stability and (c) optical/luminescence properties. Of special interest is the preparation of several quasi-1D microstructures – fibres, rolls, and tubes – which are rarely synthesized via soft chemical routes. The optical quality of some of the 1D structures is demonstrated by their light guiding capability. Although some materials had an intrinsic luminescence, trivalent rare-earth impurity ions were introduced during the synthesis for more robust luminescence functionality. Moreover, the fine structure analysis of the luminescence spectra complemented with XRD and Raman-scattering studies allowed monitoring of the structural evolution of the materials during the post-synthesis heat treatment period. Several aspects of the influence of high temperatures (>1000 °C), as well as the peculiarities of rare earth emission centres, have been clarified for studied oxide materials.