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Achievements
Last Update
13.07.2018

It was found that adding niobium drastically increases activator luminescence intensity in ZrO2 matrix, which makes Ln3+ doped zirconia even more attractive for various practical applications. Although this study was based on the luminescence of the Er ion, the phase stabilization, charge compensation, and luminescence properties are expected to be similar for other lanthanide elements. Results suggest that the luminescence intensity of other oxide matrices where lanthanides incorporate in place of tetravalent cations could be increased by addition of Nb ions.

Luminescence properties of ZnO are carried out as the material is applicable in various fields – as fast scintillators, for new generation of luminescence-based light sources, conductive and transparent thin coatings, new generation of laser materials etc. Luminescence and fast induced absorption studies of ZnO monocrystals, nanocrystals as well as ceramics provided new information and understanding of processes inside the material.

Advancements in various PEO directions were achieved:

1) For the first time, luminescence from PEO coating was observed (Eu3+ in Al2O3 matrix)

2) A new doping technology was developed for PEO coatings (three-stage pore filling)

3) PEO coating for dosimetry applications

During the past decade a number of results of fundamental and applied importance for SiO2-based optical materials have been obtained in the Amorphous materials spectroscopy laboratory:

The exact optical properties of technologically important interstitial chlorine molecules in synthetic SiO2 glass were determined and the photochemical formation of interstitial Cl2O molecules by reaction of interstitial Cl2 with photolytic interstitial O atom was detected for the first time.

The influence of the amorphous state of SiO2 on point defect formation has been studied, and it was shown that vacancy-interstitial (Frenkel) mechanism is more efficient than bond dissociation (“dangling bond”) mechanism, while both mechanisms are enhanced by the glassy disorder.

The diffusion of interstitial O2 molecules and interstitial O atoms in the glass network of SiO2 was studied by 18O isotope enrichment, and it was found that the thermal diffusion of O proceeds with network exchange in the form of peroxy linkages (Si-O-O-Si bonds), while excited-state O atom can diffuse as interstitial without exchanging with network oxygens.

Optical absorption spectrum of oxygen dangling bonds (“NBOHC’s”) in irradiated glassy SiO2 in deep-UV and vacuum UV region has been established. This defect is of particular practical importance since it is an efficient absorber and it is present in any irradiated SiO2 glass. However, until our work the exact deep-UV-VUV spectrum was not known due to interference from other overlapping optical bands.

Luminescence of phosphorus-related defects in SiO2 glass and crystals has been investigated, a new ultraviolet emission band (4.6eV) with associated 7.1 eV excitation band was found and related to tetrahedrally coordinated phosphorus atom (P2+ -center or PO43 complex ion) in SiO2 network.

Luminescence of intrinsic oxygen-deficiency related defects and excitons in different SiO2 polymorphs have been studied and reviewed.

These studies are well-known among the international community working in this field, and the laboratory researchers have co-authored several review articles on these topics.