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                         Material synthesis and spectroscopy investigation

 

Material syntheses

The large majority of investigated materials are prepared in our lab. Glasses (bulks, thin films and submicron spheres) and the most of self-organized nanostructural materials are obtained by sol-gel method, particularly by polycondensation of metal alcoxides (i.e. TEOS, TMOS, TBOT). Nanocrystalline powders are prepared mainly by the Pechini method, microwaved hydrothermal method, combustion and co-precipitation.

 

Nanoceramics

The nanoceramics are fabricated from the nanocrystalline powders (diameters were ca. 10-50nm) by a low temperature - high pressure (LHTP) technique (T-450-1000oC, p=2-8GPa). Our transparent nanoceramics (Nd3+: YAG, Ce3+:YAG) possess interesting optical properties, BaTiO3 nanoceramics -       electrical properties, GaN nanoceramics - magnetic ones. More in pdf >>>
 

Spinel Type Oxides MeFe2O4 - Ferrites

 

Spinel-type oxides MeFe2O4 (where Me is a divalent metal – cobalt, nickel, zinc, manganese), which include the magnetic ferrites, are often denoted by formula AB2O4, where A and B refer to tetrahedral and octahedral sites, respectively. In the synthesis of ferrites we attempt new combustion method. More in pdf >>>

 

Silvered Silica Based Nanomaterials

The preparation procedures and characterization of nanosized materials are extensively investigated, recently. Silica nanoparticles may be used in many applications, including ceramics, chromatography, catalysis, and can be doped by various substances that can change their properties. Antibacterial materials are required to be chemically durable and are required to slowly release silver ion for a long period. More in pdf >>>

Rare-Earth Doped Nanocrystalline Phosphors

The one of parts of our activities is designing, fabrication and characterization of efficient rare-erarth (Ce, Eu, Tb, Pr, Er, etc.) doped nanocrystalline phosphors. As a matrix we use different nanocrystallites of oxides, garnets and silicates (Lu2O3, YAG, Y2Si2O7, SnO2, Y2O3, CaTiO3 etc.). Fabricated mterials can be applied as RGB phosphors in many types light emitting devices or displays (FED, PDP, white LEDs, ELD). The rare-earth doped luminescent nanoparticles could be used in many different applications. The lightening, documents protection, biomedical and microfluidics applications are only a selected examples of them. More in pdf >>>

 

Nanopowder La0.8Sr0.2MeO3 for Solid Oxide Fuel Cells (Me = Mn, Co, Cr)
Strontium-doped lanthanum chromate La1-xSrxCrO3 (LSC) is the most used cathode material in modern Solid Oxide Fuel Cells (SOFC) . A large quantity of LSC is required for making MW scale SOFC units. Many methods of preparation has been reported by various researchers. In this work, a glycine/nitrate powder synthesis method has been described using a unique combination of metal nitrates, glycine stoichiometrically and self-combustion process, which produces nanoparticle LSC powder. More in pdf >>>
 

Luminescent and Conductive Submicron Core-Shell Structures

The core-shell structures have attracted a great attention. Beyond the diagnostic or pharmacology core-shell structures could find a potential application as phosphors, photonic crystals and as catalytic agents. The two main advantages of that kind of structures over monolithic materials are: possibility of fabrication of new composite material connecting the unique properties of core and shell and lower (comparing to monolithic materials) fabrication costs – a cheap core can be covered by expensive shell. Our efforts focus on fabrication of luminescent core-shell structures: Eu3+:YAG/SiO2, Tb3+:YAG/SiO2, Eu3+:SnO2/SiO2 and conductive nanocrystalline shells on dielectric core: ITO/SiO2, ITO/Eu3+:Y2O3. More in pdf >>>
 

Indium Tin Oxid ITO Nanocrystallites Powders and Thin  Films

The indium tin oxide (ITO) is widely applied in photonics and optoelectronics. The transparent and conductive thin films as well as semiconductive indium tin oxide nanopowders play an important role in different electronic devices. The ITO-glass slides are used as transparent front plate electrodes in construction of some types of displays. The Sn:In2O3 slides and powders may be applied also as solar cells materials anti-static, anti-glare coatings, conductive pasts, heatable glass thermal insulation of windows or prevention of radiative cooling. The ITO thin films are also able to be used in gas sensing. More in pdf >>>

  Thermoinsulating Materials

 The sol-gel technology allows to fabricate insulating porous materials with very low thermoconductivity (<0.05 Wm K ). During manufacturing the following components were used: silicon dioxide,sodium water glass and waste powders (slimic and diatomite) or ferrites. The samples were dried at 80°C and then heated at 250° - 600°C. The form glass TIM were fabrocated at relativly low temperature (<600 °C). More in pdf >>>

Thin Film Dye-Sensitzed Solar Cells

 A dye-sensitized solar cell (DSSc or DSC) is a relatively new class of low-cost solar cell, that belong to the group of thinfilm solar cells. It is based on a semiconductor formed between a photo-sensitized anode and an electrolyte, a
photoelectrochemical system.This cell is extremely promising because it is made of low-cost materials and does not need elaborate apparatus to manufacture. In bulk it should be significantly less expensive than older solid-state cell designs. More in pdf >>>

Spectroscopy
 
We deal mostly with Ln-doped glasses, crystals, powders and ceramics. With our research we try to explore and describe the transfer mechanisms between sensitizer (mostly Yb3+) and the activator ions (Tb3+, Eu3+, Nd3+, Pr3+). Another field of our investigations are rare-earth doped nanomaterials and size-effects on their luminescence properties. Such materials are important for design of new generation luminophores and photonic systems. Very interesting are also optical properties of nano-ceramics and nano-composites doped with RE, which can be use as better quality substitute for conventional laser ceramics. With our research we try to explore and describe the transfer mechanisms between sensitiser (mostly Yb3+) and the activator ions (Tb3+,Eu3+,Nd3+,Pr3+).