Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/19024
Title: Synthesis And Characterization Of CaF2:Yb,Er(CORE) /CaF2(SHELL) Up-Conversion Nanoparticles
Authors: LIU ZHENGYI
Keywords: CaF2, rare-earth doping, up-conversion, core-shell structure, near infrared, thermal decomposition, silica coating
Issue Date: 3-Aug-2010
Source: LIU ZHENGYI (2010-08-03). Synthesis And Characterization Of CaF2:Yb,Er(CORE) /CaF2(SHELL) Up-Conversion Nanoparticles. ScholarBank@NUS Repository.
Abstract: The synthesis of monodispersed CaF2:Yb,Er up-conversion nanoparticles (particle size ~ 5.4 nm ? 0.9 nm) using thermolysis of precursors in oleylamine at 340 oC was studied. These nanoparticles were characterized using TEM, XRD, FTIR, Zeta potential, DTA/TGA and XPS. An undoped CaF2 shell was subsequently deposited on the doped core nanoparticles to form the CaF2:Yb,Er(core)/CaF2(shell) structure in order to improve the emission intensity. The critical shell thickness was determined to be ~ 2.5 nm which improved the emission intensity by more than 20 times. Both core and core/shell nanoparticles were stable in solvents such as chloroform and hexane. Amorphous silica coating on CaF2:Yb,Er(core)/CaF2(shell) UCNPs was also achieved to demonstrate the potential for bio-application. CaF2:Yb,Er(core)/CaF2(shell) up-conversion nanoparticles showing strong red emission, with its longer wavelength and penetration distance compared with that of shorter wavelengths of green and blue lights, may find promising potential applications.
URI: http://scholarbank.nus.edu.sg/handle/10635/19024
Appears in Collections:Master's Theses (Open)

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