Preparation and Luminescence Characteristics of Nano BaHfO3:Ce3+ Powders Prepared by Citric Acid Chelating Process

Abstract:

Citric acid chelating method was used to prepare Ce3+ doped BaHfO3 nano-powder. TG-DTA, XRD and SEM were employed to characterize the powder. The excitation and emission spectra of the specimens were analyzed by the fluorescence photometer. Results show that BaHfO3:Ce3+ nanometer powder with high degree of crystallinity, nearly spherical morphology and 40 nm particle size could be synthesized after the precursor gel prepared under the condition of CA:EG=1:3 was calcined at 1050 ℃ for 2 h. The maximum relative intensities of the excitation spectra and emission spectra appeared for the BaHfO3:Ce3+ specimen with Ce3+ doped concentration of 0.9 mol%. The excitation spectrum has two relatively wide spectrum bands where there are maximum peak values at the wavelength of 393 nm and 445 nm, respectively. The emission spectra at lex= 393 nm and lex=445 nm also have two spectrum bands where exist maximum peak values at 530 nm and 590 nm, respectively, corresponding to 5d→2F5/2 and 5d→2F7/2 transitions of Ce3+ cation, respectively. The emission spectra at 393 nm and 445 nm are obviously different, because the 4f ground State of Ce3+ cation is formed by two energy levels, with the energy difference of about 2000 cm-1.

Key words:scintillation ceramics; citric acid; sol-gel process; BaHfO3:Ce3+ nano-powder; luminescence characteristic