The Active‐Core/Active‐Shell Approach: A Strategy to Enhance the Upconversion Luminescence in Lanthanide‐Doped Nanoparticles

Abstract Nanoparticles of NaGdF 4 doped with trivalent erbium (Er 3+ ) and ytterbium (Yb 3+ ) are prepared by a modified thermal decomposition synthesis from trifluoroacetate precursors in 1‐octadecene and oleic acid. The nanoparticles emit visible upconverted luminescence on excitation with near‐infrared light. To minimize quenching of this luminescence by surface defects and surface‐associated ligands, the nanoparticles are coated with a shell of NaGdF 4 . The intensity of the upconversion luminescence is compared for nanoparticles that were coated with an undoped shell (inert shell) and similar particles coated with a Yb 3+ ‐doped shell (active shell). Luminescence is also measured for nanoparticles lacking…

• RS
  Royal Society
• NS
  Natural Sciences and Engineering Research Council of Canada