Broadband photoluminescence of hybrid Si/SiOx nanoparticles synthesized from silicon monoxide

• Published in: Nanotechnologies in Russia Vol. 10; no. 9-10; pp. 802 - 813
• Main Authors: Rybaltovskii, A. O., Zavorotnyi, Yu. S., Sviridov, A. P., Feklichev, E. D., Ishchenko, A. A., Bagratashvili, V. N.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.09.2015
• Subjects: Chemistry and Materials Science; Industrial and Production Engineering; Machines; Manufacturing; Materials Science; Nanotechnology; Processes; DMSO Molecule; Silicon Nanoparticles; Crystalline Nucleus; Bleaching Rate; Silicon Monoxide
• ISSN: 1995-0780; 1995-0799
• DOI: 10.1134/S1995078015050183

Hybrid nanoparticles npSi/SiO x , having bright broadband photoluminescence (PL), have been synthesized using thermal disproportionation of silicon monoxide method and were used to derive sols and polymeric composites in the form of microdispersed PTFE particles and PBMA films. The peculiarities of behavior of both shape and intensity of inhomogeneously broadened PL band’s under laser excitation were determined for npSi/SiO x in sols and composites. Theese peculiarities are caused by relatively wide distribution of Si nuclei, quantum-confinement shifts in absorption (monocrystalline Si nucleus) and photoluminescence (oxygen deficient centers (npODC) in the amorphous SiO x shell) along with the effect of saturation of PL. Continuous laser exposure (at wavelength of 405 nm) of npSi/SiO x sols and composites causes the bleaching of PL. Kinetics of PL bleaching is individual for each sample type, however it always has a substantially nonexponential behavior and the bleaching rate falls two orders after ∼10 3 s of photoirradiation. The effect of postradiation restoration of the PL after the end of laser photoirradiation is revealed. Kinetics of restoration is essentially nonexponential, but individual for each sample type. Full restoration of PL band’s both intensity and shape for all samples requires no less than 15 h after the end of laser photoirradiation. Restoration completeness reveals the complete reversibility of PL bleaching in all npSi/SiO x based systems studied. A model is considered in which PL bleaching is caused by electron transfer from photoexcited npODC to a suitable trap and further posttreatment restoration of the PL caused by the tunneling recombination of electrons and ionized npODC + . The possibility of controlling the npSi/SiO x photosensitivity is discussed based on creating a specific shell around npSi/SiO x stimulating or, conversely, overwhelming the photoinduced charge separation.