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Synthesis of rare-earth doped fluoride and oxyfluoride glass ceramics and nanocomposites.

Spectroscopic properties of rare-earth activated bulk materiāls are extensively studied many years.Based on these studies novel lasers, colour displays, light emiters and etc. are developed. Nanocomposites possess many intriguing properties which are not present in corresponding bulk materials. Therefore nanocomposites can be used in the fields, where the application of bulk materials is impossible, for example, in bionanotechnology, in nanophotonic, etc.In our laboratory the synthesis of nanoparticles is adopt and modified for the synthesis of rare-earth (RE) activated NaREF4 and BaREF4 nanocomposites. In addition it is working on a synthesis of new transparent oxyfluoride glass ceramics.

Studies of radiation energy transfer and relaxation mechanisms in doped nanocomposites by means of optical spectroscopy methods.

One of possible application of nanostructures is related with optical properties including luminescence of nanoparticles. In our lab photoluminescence spectra and kinetics of rare-earth activated complex fluoride nanostructures are studied in wide spectral and temperature range. Exciting radiation energy transfer and relaxation processes resulting in photoluminescence are studied. Much attention is paid for studies of upconversion processes in rare-earth doped nanofluorides which involve the absorption of multiple photons (usually IR) and subsequent emission of one single photon (VIS or UV).

Wide band gap materials

Research works by the Laboratory are focused on light-induced processes and defect luminescence in wide band gap solid state materials, such as III group nitrides, oxides and other materials available in the form of bulk and nanosize structures, in order to detect:

  • spectral characterization of materials containing absorption, photoluminescence and its excitation spectra ensuring spectral pasport of material;
  • defect-induced luminescence mechanisms, structure of luminescent defects and their behavior in materials;
  • processes of energy transfer between defects and host lattice;
  • influence of material size on luminescence properties (macrosize and nano-structures in 1D, 2D and 3D forms);
  • estimation of practical applications of materials for UV light dosimeters, gas sensors, UV and visible light emitters;
  • development of new materials for white light emitters with specific properties.

Research includes different spectral characterizations of materials in temperature range between 8 K and 300 K such as absorption/transmission spectra within the spectral range between 190 nm and 1100 nm, photoluminescence spectra (between 250 nm and 1500 nm) and its excitation spectra as well as optically and thermally stimulated luminescence and luminescence polarization measurements.

  • Magnetic resonance spectroscopy (EPR, ODMR);
  • Research of defect structure and luminescence mechanisms in fluoride, oxide crystals, oxyfluoride composites, and application of the materials.