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Synthesis, Local Structure and Optical Properties of Tb3+ Doped 12CaO·7Al2O3

Author: XueLinLin
Tutor: LiuYuXue
School: Northeast Normal University
Course: Condensed Matter Physics
Keywords: 12CaO · 7Al2O3 Tb3 ion Absorption spectrum Cross relaxation Energy transfer
CLC: O482.3
Type: Master's thesis
Year: 2009
Downloads: 70
Quote: 8
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Abstract


In this paper, chemical coprecipitation Prepared Tb 3 doped 12CaO · 7Al 2 O 3 (C12A7) samples by X-ray diffraction (XRD ), micro-Raman spectroscopy, scanning electron microscopy characterization of the micro-structure of C12A7: Tb; test means to study the optical properties of the sample with the absorption, excitation spectra and emission spectra. XRD and Raman spectroscopy results show that have been obtained with a cage-like structure of the single-phase C12A7 powder, at the same time the Tb crystal may be incorporated into the Sites of. The scanning electron microscope to the synthetic the C12A7: Tb powder particle size of 200-300 nm, the doping concentration of 5 at.% Of the sample surface of each grain has 100 nm of microporous. Was observed in the absorption spectrum and the excitation spectrum to the absorption of the matrix and Tb 3 4f-5d transitions. Using 280 nm wavelength UV excitation, observed in the different TB ion doping concentration of the emission spectrum. Lower concentration of doping conditions, the spectrum can be divided into two parts: 470 nm blue emission 5D3 → 7FJ and 5D4 → 7FJ (J = 6, 5, 4 and 3), the green emission; higher concentration of doped heteroaryl under the conditions, the green emission is dominant. This is due to the cross relaxation process occurs. High concentrations when two Tb 3 in close proximity, the ions will produce non-radiation energy transfer processes, the 5D4 level on the Tb 3 Layout increase, 5D3 level of Tb 3 layout reducing the number. Cross relaxation process makes derived 5D3 energy level transitions of the emission intensity (blue emission) quenching, from the 5D4 energy level transitions of the emission intensity (green emission) enhancements. 5D4 transitions to the ground state emission intensity curve found by analysis of the concentration quenching with Tb 3 increase of the concentration and weakened, and the 5D3 transition to the ground state emission intensity with the Tb 3 The increase in the concentration of the first enhanced and then weakened. Caused by curve fitting 5D3 → 7FJ and 5D4 → 7FJ transition luminescence concentration quenching interactions of type. 5D3 → 7F5 transition concentration quenching is mainly due to the electric dipole - electric dipole interaction results corresponding to 5D4 → 7F5 transition concentration quenching between close neighbors Tb 3 ion exchange with each other induced. 488 nm excitation under different concentrations of the C12A7: the Tb of 3 Variable for Luminescence characteristics is also increased as the temperature rises to the luminous intensity of the samples was observed, indicating that the samples prepared in thermal stability. Our experimental results show that the the C12A7 material is an ideal fit for the Tb-doped matrix material and its strong green emission, shows that the C12A7: TB can be used in the field of display and lighting, etc..

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CLC: > Mathematical sciences and chemical > Physics > Solid State Physics > Solid nature of the > Optical Properties
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