Synthesis and characterization of near-infrared light triggered lanthanide-doped upconversion nanocrystals

• Main Authors: Yi-Husan Hsu, 徐憶瑄
• Other Authors: Chien-Hong Chen
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/08626558123607409893

碩士 === 中山醫學大學 === 應用化學系碩士班 === 103 === This study mainly discusses the synthesis of NaYF4/LiYF4 nanoparticles containing Tm3+/Yb3+. The upconversion efficiency of these nanoparticles correlated to the equivalent of activator or base during the syntheses is also demonstrated. The TEM images of the particles prepared by autoclave under lower temperature show that most of the particles are irregular (AC7 and AC14). In the meantime, the particles could not show the upconversion efficiency under 980 nm excitation. In order to improve the diameter and the upconversion efficiency of the nanoparticles, we used the heating mantle for the synthesis of the nanoparticles. The nanoparticles with upconversion efficiency and diameter less than 100nm are successfully synthesized. To study the relationship between the equivalent of the activator / base and the upconversion efficiency of the nanoparticles, we increased the equivalent of the activator. The result indicated that the upconversion efficiency was not enhanced by increasing the equivalent of the activator. However, the increasing the equivalent of the base ( LiOH / NaOH) during the synthesis resulted in the enhanced upconversion efficiency of the nanoparticles. The further addition of Y(CH3CO2)3 and base (LiOH / NaOH) to the synthesized NaYF4/LiYF4:Yb,Tm nanoparticles by the heating mantle led to the formation of new nanoparticles. The TEM images of the nanoparticles show that the shapes of the nanoparticles transformed from hexagon to rod (L1S、L3S、N1S、N3S). The analysis of the length-to-width (aspect ratio, AR) of the rod (L1S (AR=3.90), L3S (AR= 3.77); N3S (AR=3.73), N1S (AR=2.64)) showed that the rod with the higher AR value exhibited the effective upconversion efficiency.