Luminescent Materials

Luminescent Materials

Group leader: Mikhail Brik, Institute of Physics, University of Tartu

The members of research group are highly experienced in experimental and theoretical research of the electronic properties of optical materials, including the study of excitation, energy relaxation and luminescence processes in (wide band-gap) insulator materials of various morphologies. In recent years, the main focuses have been placed on: a) the development of new materials for various applications (scintillators, dosimetry materials, LED’s, sensorics media, optical windows, etc.) with a special emphasis at pure and doped oxides (tungstates, molybdates, titanates, borates, phosphates, apatites, hafnia, zirconia) and fluorides in macro- and nano-scale (incl. low-dimensional systems, e.g., thin films); b) research on non-proportional response in scintillators, development of models for fast relaxation processes in scintillators; c) the development of theoretical models predicting structural and electronic properties for new materials classes; d) research on luminescence properties of rare earth and transitions metal ions for various applications; e) band structure parameters.

The group has developed advanced research equipment, which provides possibilities for a) time-resolved luminescence measurements in the micro- and nanosecond range under photoexcitation ranging from visible to VUV and excitation by pulsed electron beam, both in the temperature interval from 2 to 800 K, to study the evolution of electronic excitations and their quenching mechanisms; b) the PSL and TSL measurements to investigate charge carrier trapping and related phenomena; c) advanced solid state and combustion synthesis, crystal growth and thermochemical treatments of materials under investigation, production of thin film films by pulsed laser deposition, spin-coating and sol-gel chemistry methods. The group takes part also in the development of two photoluminescence setups covering the VUV to soft X-ray excitation ranges, the synchrotron facilities of Hasylab in Germany and MAX IV in Sweden, which will be commissioned for research in 2016.

On the theoretical side, Prof Brik and co-workers have established a good reputation in the fields of the ab-initio calculations of physical properties of functional materials (pure and doped with 3d/4f ions) and crystal field theory and its application to the 3d/4f ions, relations between ab-initio and semiempirical models. In particular, the method of positioning all impurity ion energy levels in the host band gap has been developed by Prof. Brik. An extensive network of active on-going international collaboration, which includes many research groups from universities across Europe, USA and Asia and from industry (such as GE Global Research, Samsung R&D, Japan) has been established. Many invited and oral presentations were delivered at major international conferences. Prof. Brik is also an Editor of the Optical Materials journal (Elsevier).