Size Effect and Various Dopant Concentration Effects in the Preparations of Lanthanide-Doped Core/Shell Upconversion Nanocrystals, NaYF4: Gd/Pr/Sm/Ho/Tb
Yihjaan Tsai1*, Yawteng Tseng1,2, Chun-Rong Lin1,2
1Applied Physics, National Pingtung University, Pingtung, Taiwan
2Functional Materials Research Center, National Pingtung University, Pingtung, Taiwan
* presenting author:Yawteng Tseng,
Upconversion is an optical process that involves the conversion of lower-energy photons into higher-energy photons. By using the core/shell structure, the lanthanide-doped upconversion nanocrystals (NCs) proved to improve the luminescence efficiency. NaYF4 has been shown to be one of the most efficient host materials in the core/shell upconversion lanthanide ions. The size of the NCs was shown to affect the spectra by changing its geometry. Meanwhile, the activator and sensitizer dopant concentrations significantly affect upconversion luminescence. We have observed the preliminary change in geometry from cubic to hexagonal by doping of gadolinium to the NaYF4 under TEM. In this study, a systematic and comparative work of various lanthanide dopants, Gd/Pr/Sm/Ho/Tb, will be presented in order to see the effects of size and dopant concentration on the luminescence efficiency.

Keywords: Upconversion, Nanocrystals, lanthanide, core/shell