CeIV-GdIIIMixed Oxides as Hosts for ErIII-Based Upconversion Phosphors.
A family of ErIIIand ErIII-YbIIIbased nanophosphors, hosted in monophasic oxidic CeIV-GdIIIbinary solid solutions, was prepared. The samples were formulated with a constant ErIIIcontent as the activator, with the eventual addition of YbIIIas a sensitizer. The amorphous Ce0.94-xGdxEr0.06(OH)CO3⋅H2O and Ce0.94-xGdxEr0.05Yb0.01(OH)CO3⋅H2O precursors were prepared by following the urea method to obtain monodispersed spheres of tunable size ranging from 30 to 450 nm. After being decomposed at 1273 K under an atmosphere of air, the precursors of 200 nm in diameter evolved into monophasic polycrystalline particles preserving the parent shape and size. The role of the composition of the binary matrices in the emission properties was evaluated for two different excitation wavelengths (976 nm and 780 nm) based on the upconversion (UC) emission spectra and their dependence on the incident power. The yield of the UC process is discussed in the framework of established and novel alternative mechanisms. The number of vacancies and mainly the symmetry of the ErIIIenvironment play major roles in the deactivation pathways of the UC emission mechanisms. However, the colours obtained by employing bare CeIVor GdIIIhosts are preserved in the related monophasic CeIV-rich or GdIII-rich binary hosts.
Departamento de Química Inorgánica Analítica y Química Física FCEyN-Universidad de Buenos Aires, INQUIMAE-CONICET, Ciudad Universitaria Pabellón 2, C1428EHA, CABA, Argentina.
Cecilia
C
Sorbello
Institute for Physics, Carl von Ossietzky University, Carl-von-Ossietzky-Str. 9, 26129, Oldenburg, Germany.
Petra
P
Gross
Physikalisches Institut and Center for Nanotechnology (CeNTech), Westfälische Wilhelms-Universität Münster, Heisenbergstraße 11, 48149, Münster, Germany.
Cristian A
CA
Strassert
Departamento de Química Inorgánica Analítica y Química Física FCEyN-Universidad de Buenos Aires, INQUIMAE-CONICET, Ciudad Universitaria Pabellón 2, C1428EHA, CABA, Argentina.
Matías
M
Jobbágy
Departamento de Química Inorgánica Analítica y Química Física FCEyN-Universidad de Buenos Aires, INQUIMAE-CONICET, Ciudad Universitaria Pabellón 2, C1428EHA, CABA, Argentina.
Beatriz C
BC
Barja
energy transfer; lanthanides; luminescence; photochemistry; solid-state structures