Abnormal photothermal effect of laser radiation on highly defect oxide bronze nanoparticles under the sub-threshold excitation of absorption

5th International Congress on Energy Fluxes and Radiation Effects 2016

Gulyaev, P.^1 ; Kotvanova, M.^1 ; Omelchenko, A.^2

Physics and Chemistry Department, Ugra State University, 16 Chekhov St., Khanty-Mansiysk

628012, Russia^1

Institute Photonic Technologies, Federal Scientific Research Centre Crystallography and Photonics of RAS, 2 Pionerskaya St., Moscow

142190, Russia^2

关键词: Cartilaginous tissues;    Dispersion energies;    High-resolution TEM;    Non-stoichiometric composition;    Photothermal effects;    Radiationless transition;    Sub-threshold excitation;    Superficial defects;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/830/1/012153/pdf
DOI  :  10.1088/1742-6596/830/1/012153

来源: IOP

【 摘 要 】

The mechanism of abnormal photo-thermal effect of laser radiation on nanoparticles of oxide bronzes has been proposed in this paper. The basic features of the observed effect are: a) sub-threshold absorption of laser radiation by the excitation of donor-like levels formed in the energy gap due to superficial defects of the oxide bronze nano-crystals; b) an interband radiationless transition of energy of excitation on deep triplet levels and c) consequent recombination occurring at the plasmon absorption. K or Na atoms thermally intercalated to the octahedral crystal structure of TiO2in the wave SHS combustion generate acceptor levels in the gap. The prepared oxide bronzes of the non-stoichiometric composition NaxTiO2and KxTiO2were examined by high resolution TEM, and then grinded in a planetary mill with powerful dispersion energy density up to 4000 J/g. This made it possible to obtain nanoparticles about 50 nm with high surface defect density (1017-1019cm-2at a depth of 10 nm). High photo-thermal effect of laser radiation on the defect nanocrystals observed after its impregnation into cartilaginous tissue exceeds 7 times in comparison with the intact ones.