research areas experimental techniques

The area of my reasearch intrests are optical investigations (absorption, emission excitation and time decay) of undoped semiconductor nanocrystals in the form of freestanding powders, nanocrystaline films as well clusters undoped, doped or co-doped with the lanthanide ions .My research are focused on the absorption and relaxation processes in these materials and in particulary on the energy transfer processes, where the excitation energy is transferred from the donor (host matrix, nanocrystal, lanthanide ion) to the acceptor (lanthanide ion). Recently, I have focused my research activities mainly on three following topics:

Optical spectroscopy of silicon based nanostructures [lanthanides doped]
Increasing intrest in synthesis and investigations of Si nanocrystals originates mostly from the observation of room-temperature, nanocrystalline-size-dependent photoluminescence in the visible spectral range. This gives possibilities for light emitting devices and lasers based on silicon in CMOS technology. Moreover, this material seems to be very promising for III-generation of photovoltaics and can play a sensitizating role in the excitation processes of co-doped into such system lanthanide ions. This approach can give a possibility of obtaining LED's, lasers or light amplifiers in infrared spectral range obtained in CMOS technology.

In collaboration with:
-McMaster University, Hamilton, Ontario, Canada
-Photovoltaics Centre of Excellence Address: University of New South Wales, Sydney, Australia

(a) SRSO/SiO2 multilayer system containing Si nanocrystals in each SRSO layer [Optics Expess 2010], (b) schematic representation of energy transfer process from Si nanoparicles to Nd ions [ECSSL 2010]

Synthesis and optical spectroscopy of inroganic nanocrystals doped by lanthanide ions for bio-medical applications
The cells of living organisms are of the size of 10 micro.m. However, their individual components are much smaller and reach the size of sub-microns, e.g. proteins are of 5 nm in diameter. Such a small dimension is a reason why it is impossible to directly observe them by classical reflection and transmission microscopy. To avoid this restriction the special molecules called molecular markers or inorganic markers [nanocrystals or quantum dots] are injected into the cells. These markers exposed to VIS-UV light start to emit photons and investigated cells can be observed under microscope. This technique is called fluorescent microscopy.
In our Team we are synthesizing mainly: NaYF4-based nanocrystals doped by lanthanide ions as well II-VI-based nanocrystals doped bylanthanide ions where both class of these materials use the concept of energy transfer or up-conversion processes for lanthanides ions excitation.

In collaboration with:
-Medical Faculty, Department of Immunology and Immunotoxicology, Slovak Medical University, Bratislava, Slovakia
-Institute of Macromolecular Chemistry AS CR, Prague, Czech Republic
-Institute of Cell Biology, National Academy of Science of Ukraine, Lviv, Ukraine
-NanoBioMedical Centre, Adam Mickiewicz University, Poznan, Poland

Examples of nanocrystals doped by lanthanides with red emission

Synthesis and optical spectroscopy of semiconducting nanostructures

In collaboration with:

CdSe based nanostructures, Credit to Maciej Chrzanowski

optical imaging

In collaboration with:

Different modes of optical imaging