New, thermally stable Gd(GeO)(PO)O-based upconversion phosphors.

A series of GdYbErGePO germanate phosphates differing in the ratio of the Yb and Er active ions have been synthesized, and their luminescence spectra have been measured. According to X-ray diffraction characterization results, all of the synthesized germanate phosphates are single-phase and have a triclinic structure (sp. gr. P1). We have measured upconversion luminescence spectra due to the Er H, S → I and F → I radiative transitions in the synthesized gadolinium ytterbium erbium germanate phosphates and determined the luminescence upconversion energy yield ( B ) in GdYbErGePO. The effects of the concentrations and ratio of the dopants in the Gd(GeO)(PO)O germanate phosphate host on B and the ratio of the luminescence intensities in the red and green spectral regions ( R/G) have been assessed. [ABSTRACT FROM AUTHOR]