Oleic acid-modified LiYF₄:Er,Yb nanocrystals for potential optical-amplification applications

LiYF₄:18%Yb,2%Er nanocrystals and NaYF₄:18%Yb,2%Er nanoparticles (NCs) were synthesized by a solvothermal approach using oleic acid (OA) as the surfactant. With the excitation of a 980 nm diode laser, LiYF ₄:18%Yb,2%Er NCs exhibit more strong emission than alpha-NaYF ₄:18%Yb, 2%Er at around 1530 nm. The TEM images showed that the LiYF₄:18%Yb, 2%Er NCs have a nearly spherical shape and the size is about 15 nm. The OA-capped LiYF₄ NCs have excellent dispersibility in organic solvents. These results showed that LiYF₄:18%Yb, 2%Er NCs are a promising material for polymer-based optical waveguide amplifiers.