(Herbert Buerger)
Investigations on sol-gel-technology are focused on the improvement of physical properties and new applications. Here, the preparation is carried out on the base of alkoxides, anorganic-organic hybride polymers, inorganic salts using spray-, dip-, and spin-coating procedures.
The main topic is the correlation of the preparation parameters, the structural parameters during the sol-gel transition, those of the thermally treated coating and the physical properties of the layers. Here, numerous characterization techniques are used: rheological measurements, transmission electron micro-scopy, atomic force microscopy, Rutherford-backscattering, X-ray photoelectron spectroscopy, infrared-, UV/VIS-spectroscopy and various techniques to measure optical properties, including optical non-linearity.
At the moment, one of the main topics is the preparation of coatings possessing high values of third order optical non-linearities and low attenuation. There, semiconductor nanocrystals are incorporated into the coating. In the past, predominantly CdS and CdSe nanocrystals were studied. Actually, also other semiconducting nanocrystals, such as group IV and III/V are studied.
Other topics are the preparation of photochromic layers and powders. There, Ag and Cu-halides are photoactive components.
Besides, semiconducting TiO2 in layered structures is modified by doping with respect to its band gap. This enables the photocatalytic decomposition of organic compounds, especially those with carbon-chlorine bonds.