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Title: Synthesis And Characterization Of CaF2:Yb,Er(CORE) /CaF2(SHELL) Up-Conversion Nanoparticles
Keywords: CaF2, rare-earth doping, up-conversion, core-shell structure, near infrared, thermal decomposition, silica coating
Issue Date: 3-Aug-2010
Citation: 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.
Appears in Collections:Master's Theses (Open)

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