Semana de Nanotecnología 2013

We present the effects of Ag -doping and after-growth thermal annealing on the photoluminescence (PL) and thermoluminescence (TL) behaviors of SnO₂ nanoparticles. SnO₂ nanoparticles of 4-7nm size range containing different Ag contents were synthesized by hydrothermal process.

It has been observed that the after-growth thermal annealing process enhances the crystallite size and stabilizes the TL emissions of SnO₂ nanostructures. Incorporated Ag probably occupies the interstitial sites of the SnO₂ lattice, affecting drastically their emission behaviors on thermal annealing. Both the TL response and dose-linearity of the Sn₂ nanoparticles improve on 1.0% Ag doping, and subsequent thermal annealing. However, a higher Ag content causes the formation of Ag clusters, reducing both the TL and PL responses of the nanoparticles. In addition, hydrothermally grown SnO₂ and SnO₂:Eu nanoparticles of 4-11 nm sizes were analyzed by PL and TL to study the effects of Eu-doping on their emission behaviors. Most of the incorporated Eu³⁺ ions remain at interstitial sites of SnO₂ lattice. High Eu-contents generate lattice deformation, formation of Eu³⁺/Eu⁰ clusters at interstitial sites, or segregation to the particle surface. Formation of Eu clusters at interstitial sites enhances defect density in the crystal lattice, reorganize carrier trapping centers, and modify their activation energies. Both the PL intensity and beta radiation dose response were significantly enhanced for 0.5 and 1.0 mol% of Eu³⁺, respectively.