Site symmetry and host sensitization-dependence of Eu³⁺ real time luminescence in tin dioxide nanoparticles

Abstract

The present work gives a detailed investigation of the dependence of the real time luminescence of Eu-doped tin dioxide nanopowder on rare earth (RE) site symmetry and host defects. Ultrafast time-resolved analysis of both RE-doped and undoped nanocrystal powder emissions, together with electronic paramagnetic resonance studies, show that host-excited RE emission is associated with RE-induced oxygen vacancies produced by the non-isoelectronic RE-tin site substitution that are decoupled from those producing the bandgap excited emission of the SnO matrix. A lower limit for the host-RE energy transfer rate and a model for the excitation mechanism are given.

SiO2-SnO2:Er3+ Glass-Ceramic Monoliths

“…The key to making the spectroscopic properties of the glass-ceramics very attractive for photonic applications is to activate the nanocrystals by using rare-earth ions as luminescent species [4]. From a spectroscopic point of view, the more appealing feature of glass-ceramic systems is that the presence of the crystalline environment for the rare-earth ions allows high absorption and emission cross sections, reduction of the non-radiative relaxation thanks to the lower phonon cut-off energy, and tailoring of the ion-ion interaction by the control of the rare-earth ion partition [5]. Here we focus on glass-ceramic photonic systems based on rare-earth activated SiO 2 -SnO 2 monoliths produced by sol-gel route.…”

“…Here we focus on glass-ceramic photonic systems based on rare-earth activated SiO 2 -SnO 2 monoliths produced by sol-gel route. Although the system has been investigated for several years, the research activity is still undergoing because of the need to develop reliable fabrication protocols and to control the ion-ion interaction [4][5][6]. Both these problems are highly detrimental for the efficiency of active devices [2,[7][8][9].…”

Site-selective symmetries of Eu3+-doped BaTiO3 ceramics: a structural elucidation by optical spectroscopy

“…Site A 1 could be related to Eu 3+ ions occupying a substitutional Ba 2+ site in a highly distorted environment in a thin shell near the grain surfaces, whereas B 1 , with a similar 5 D 0 -7 F 1 emission, but appearing at longer wavelengths, could be associated with Eu 3+ occupancy of a distorted Ti 4+ site; 41 distorted sites near particle surfaces have been observed in other Eu 3+ -doped oxide powders. 42 The TRFLN spectra display nearly equal intensities for the 5 D 0 -7 F 0 , 5 D 0 -7 F 1 and 5 D 0 -7 F 2 transitions with one, three, and five peaks, respectively, as well as an intense 5 D 0 -7 F 4 transition (see Fig. S2(a) in the ESI †), which are compatible with a C s , C 2 , or C 1 point symmetries.…”

SiO₂-SnO₂:Er³⁺ Glass-Ceramic Monoliths

“…The key to make the spectroscopic properties of the 53 glass-ceramics very attractive for photonic applications is to activate the nanocrystals by luminescent 54 species as rare earth ions [5]. From a spectroscopic point of view the more appealing feature of glass-55 ceramic systems is that the presence of the crystalline environment for the rare earth ions allows high 56 absorption and emission cross sections, reduction of the non-radiative relaxation thanks to the lower 57 phonon cut-off energy and tailoring of the ion-ion interaction by the control of the rare earth ion 58 partition [6]. Here we focus on glass-ceramic photonic systems based on rare earth activated SiO2-…”

“…which are detrimental for the efficiency of active devices, are subject of several scientific and 62 technological investigations [5][6][7]. Among the different materials that are successfully used as 63 nanocrystals to be embedded in silica matrix, tin dioxide presents specific interesting characteristics.…”