Core/shell Si/SiO x nanoparticles (Si/SiO x -NP) having bright red-infrared photoluminescence were obtained by a three-stage synthesis based on the thermal disproportionation of microdispersed SiO. Transformation patterns of structure and spectroscopic properties of the material during passage through all process stages (starting from initial SiO microparticles and up to the Si/SiO x -NP sols) have been revealed by using Raman, photoluminescence and ESR spectroscopy, XPS, XRD, and electron microscopy. Thermal annealing of SiO microparticles (stage I) results in formation of amorphous-crystalline Si nanophase in the matrix of SiO 2 , as well as generation of paramagnetic P b centres with the concentration up to 4 9 10 18 particles/g. At the annealing temperature, T an [ 900°C, a rapid growth of nanocrystal sizes takes place, and, simultaneously, a rapid growth of paramagnetic P b centre concentration occurs. Elimination of SiO 2 from the annealed sample by etching in HF (stage II) stimulates further crystallization of amorphous-crystalline core, caused by stress relaxation inside the Si core when removing SiO 2 matrix. Functionalization of nanoparticle surface (stage III) allows obtaining core/shell Si/SiO x -NP with a bright red-infrared photoluminescence and their sols. Average size of the crystalline Si core increases from 4.7 to 11.1 nm when T an at the stage I rises from 350 to 1100°C. At relatively low T an = 350°C, the nanoparticles with monocrystalline Si cores are mainly formed, while at T an [ 1100°C, a large number of polycrystalline Si nanoparticles are also observed. Our TEM images have revealed the existence of monocrystalline Si nanoparticles having significantly different contrast even at comparable nanoparticle sizes. We attribute that to the formation of both bulk (with a high TEM contrast) and flat (2D) Si nanocrystals (with a low TEM contrast) in the course of SiO annealing.

The results of laser-induced formation of luminescent structures on the surface of poly-2.2’-n-oxydiphenylene-5.5’-bis-benzimidazole films, obtained by the coating method from a formic acid solution, are presented. The structures are formed using cw 405-nm laser radiation with intensities of 102 – 104 W cm–2. It is shown (using methods of optical, atomic-force, and electron microscopy) that the structures formed on the surface are microbubble foam-like aggregations. Their formation is modelled as a sequence of the following processes: release of formic acid molecules, their condensation on matrix defects in the surface layer, and explosive boiling as a result of heating this layer of polymer film by the laser beam. The luminescence of these structures is due to the weakening of the concentration quenching from closely spaced luminescence centres in benzimidazole cycles during their emergence to the surface and the increase in the distance between them due to the extension on bubble aggregates on the surface.

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