Upconversion emission from erbium doped sol-gel derived ВаТiOз powders and coatings

Upconversion is a process where light can be emitted with photon energies higher than those of the light generating the excitation (www.rp-photonics.com/upconversion). Diverse inorganic matrices doped with trivalent lanthanides - erbium and holmium exhibit upconversion, transferring infrared light into visible. Thus the effect attracts attention for detection and visualization of infrared radiation. Recently we reported that sol-gel derived barium titanate possessing refractive index about 1.9 in amorphous state can be used as component of optical interference filter in combination with low refractive index films as silica or magnesium fluoride. At the same time room-temperature luminescence of lanthanides in sol-gel derived barium titanate makes the material and method promising for light conversion. In this work we investigate erbium upconversion emission from sol-gel derived BaTiO3 films and powders

Sol–Gel Fabrication and Luminescence Properties of Multilayer Eu-Doped BaTiO3–SiO2 Xerogel Nanostructures

With the use of sol–gel method BaTiO3–SiO2 multilayer structures were fabricated on glass or fused silica substrates employing dipping or spinning procedure. The photonic stop band was observed in the reflection and transmission spectra of the multilayer structure annealed at 450∘C. It is redshifted with an increase of the thicknesses of BaTiO3 and SiO2 layers. For structures comprising Eu-doped BaTiO3 layers of different thicknesses photoluminescence with the main band at 614nm was detected. It is characterized with the double-exponential decay with the lifetimes of about 0.5ms and 1.1ms which do not depend significantly on the photonic stop band position