Lanthanide based up-conversion materials.

CECILIA SORBELLO; PETRA GROSS; MATÍAS JOBBÁGY; CRISTIAN STRASSERT; BEATRIZ CARMEN BARJA

Córdoba

Encuentro; XI Encuentro Latinoamericano de Fotoquímica y Fotobiología (XI ELAFOT); 2012

Photon upconversion (UC) is a non-linear optical process in which the sequential absorption of two or more photons leads to the emission of light of shorter wavelength than the excitation wavelength (anti-Stokes type emission). The noninvasive nature of the incident low energy light (IR) with minimal autofluorescence and photo damage makes this process especially useful in the study of biological systems via imaging techniques. Lanthanide ions commonly have more than one metastable level and long lifetimes (10-6?10-2s) being this point the basic requirement for UC processes. The most studied pair of lanthanide dopants is Er(III)(activator) ?Yb(III)(sensitizer) mainly because the energy levels of Er(III) are capable of infrared pumping with a 980 nm laser diode ( Er(III) transition 4 I15/2 → 4 I11/2) with high efficiency which also matches the energy level of Yb(III) (2 F7/2 → 2 F5/2). In this work new potential matrices are explored using mixtures of Gd2O3 and CeO2 as hosts for the trivalent Er(III) and Yb(III) ions to investigate their ability to undergo upconversion processes. In particular cerium oxides are non-toxic and possess excellent thermal and mechanical stability. Its mutual biocompatibility with Gd2O3 and their low phonon cutoff offers a promising platform for diagnosis applications.