Synthesis and luminescence of ultrafine Er3+- and Yb3+-doped Gd11SiP3O26 and Gd14B6Ge2O34 particles for cancer diagnostics

In search of new contrast materials for NMR and fluorescence diagnostics and neutron capture therapy of cancer, we have synthesized ultrafine Er3+- and Yb3+-doped Gd11SiP3O26 and Gd14B6Ge2O34 particles and studied their luminescence properties. We measured the Er3+ upconversion luminescence spectra of the gadolinium erbium ytterbium phosphosilicates and borate germanates in the visible range and evaluated the absolute quantum yield of their luminescence. The quantum yield of luminescence in the gadolinium phosphosilicate Gd11SiP3O26 doped with 5.0 at % Yb and 2.5 at % Er is comparable to that in known Yb3+/Er3+ codoped fluorides. The nonradiative Yb3+ → Er3+ energy transfer efficiency is evaluated.