We have characterized the structure and luminescence properties for two-component material composed of nanocrystalline cellulose and nanocrystalline (less to 100 nm) silicon powder. An efficient and stable photoluminescence of nanocomposite, resistant to the influence of gas-phase oxidants, has been found. The obtained material has electret-like properties and demonstrates the possibility of multiple-recharging in an electric field near 5·103 V/cm at temperatures ranging from −70°C to 100°C. The presence of the electric field, as well as ozone or low-temperature plasma treatment, does not change the luminescence spectrum due to quantum size properties of silicon nanoparticles. We believe that these particles may appear in two states: both embedded in a cellulose matrix and in the form of mechanical mixture.

In this paper we investigate electron-beam modification and the process of subsequent recovery of phase transition parameters of VO 2 -based films within 20-100°C temperature range. It is shown that the level of electron-beam modification, i.e., resistance change value, is by an order of magnitude higher in VO 2 metallic phase compared with the semiconducting one. The time of parameter recovery in air also changes at phase transition (less than a minute for the metallic phase and more than an hour for the semiconducting one), while within each phase the temperature dependence of modification rate and recovery is negligible. The physics of the phenomena is explained by peculiarities of the processes of oxygen vacancies generation and recombination in both phases. The regularities of electron-beam modification influence on the electrical switching effect are established; particularly, the threshold voltage of switching device is found to decrease under the action of modification. Fig. 4. Kinetics of oxide film growth. Jpn. J. Appl. Phys. 54, 051102 (2015) M. A. Belyaev et al. 051102-4

The results of a systematic study of spectral and kinetic patterns of ozone-adsorption-induced luminescence (AL) in nanostructured Si and, for the first time, in colloidal CdSe/ZnS quantum dots (QDs) are reported and compared with photoluminescence (PL) of the same structures. The common excitonic nature of light emission under ozone chemisorption and photoexcitation is confirmed by excellent coincidence of AL and PL emission bands. This coincidence is maintained during correlated quenching of AL and PL emission caused by nonradiative defects generated under ozone adsorption. A possible mechanism for energy conversion is proposed in the framework of an exothermic oxidation reaction of core materials caused by ozone. The significant role of the quantum confinement effect differentiates the observed phenomenon from well-known chemiluminescence in molecular systems. This research establishes a physicochemical basis for the development of a gas sensor with high selectivity to ozone. Also, our findings may be useful for testing core-shell colloidal QDs with ozone.

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We have studied light‐induced processes in ultra‐thin porous silicon (por‐Si) impregnated with fullerene C60. After insertion of C60 molecules a photoluminescence (PL) is quenched for more than one order of magnitude. No additional EPR defects were detected under fullerene insertion as it was revealed in por‐Si powder. Under illumination in oxygen the PL intensity could be restored to nearly initial level or to yet more. Recovery degree was dependent on oxidation state of por‐Si before C60 insertion. As was observed by ellipsometry a PL recovery is accompanied with oxidation of porous layer. Observed phenomenon is related with known ability of C60 to produce singlet oxygen. We suppose that generation efficiency of fullerenes to produce singlet oxygen is enhanced by energy transfer from photoexcited nanocrystallites. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)