Ce(IV)-Gd(III) oxide hosts for Yb(III)-sensitized Er(III) phosphors: synthesis of monodispersed particles and their luminescent properties.

CECILIA SORBELLO; PETRA GROSS; MATÍAS JOBBAGY; BEATRIZ C. BARJA; CRISTIAN A. STRASSERT

Chemphyschem

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2017 vol. 18

1439-4235

A family of ErIII and ErIII?YbIII based nanophosphors, hosted inmonophasic oxidic CeIV?GdIII binary solid solutions, was prepared.The samples were formulated with a constant ErIII contentas the activator, with the eventual addition of YbIII as a sensitizer.The amorphous Ce0.94xGdxEr0.06(OH)CO3·H2O andCe0.94xGdxEr0.05Yb0.01(OH)CO3·H2O precursors were prepared byfollowing the urea method to obtain monodispersed spheresof tunable size ranging from 30 to 450 nm. After being decomposedat 1273 K under an atmosphere of air, the precursors of200 nm in diameter evolved into monophasic polycrystallineparticles preserving the parent shape and size. The role of thecomposition of the binary matrices in the emission propertieswas evaluated for two different excitation wavelengths(976 nm and 780 nm) based on the upconversion (UC) emissionspectra and their dependence on the incident power. Theyield of the UC process is discussed in the framework of establishedand novel alternative mechanisms. The number of vacanciesand mainly the symmetry of the ErIII environment playmajor roles in the deactivation pathways of the UC emissionmechanisms. However, the colours obtained by employingbare CeIV or GdIII hosts are preserved in the related monophasicCeIV-rich or GdIII-rich binary hosts.