Preparation And Properties Of Eu/Tb/Sm Doped Oxyfluoride Aluminosilicate Glasses And Glass-ceramics

Recently, white light emitting diodes (W-LEDs) as the new generation of solid state light source has attracted much attention, and shown high potential for replacement of conventiaonal lighting sources like incandescent and fluorescent lamps. Based on these backgrounds, a new kind of luminescent glass excited by UV light for application in W-LEDs has been investigated in this thesis. The Eu/Tb/Sm doped aluminosilicate glasses and glass-ceramics have been prepared by the melt-quenching method and subsequent heat treatment. The dependence of optical properties of these glasses and glass-ceramics on the glass compsitions and rare earth ions were studied via density measurement, absorption spectra, XRD measurement, luminescent spectra, EPR measurement and so on. The predominant investigation results were listed as follows.(1) Conversion of Eu3+to Eu2+occurs in Eu doped aluminosilicate glasses prepared in ambient atmosphere. The conversion efficiency is glass composition dependent. Increasing fluorine anions concentration leads to the much more easil conversion of Eu3+to Eu2+. In addition, the Eu3+to Eu2+conversion shows firstly increase and then decrease with the increasing content of B2O3. The energy transfer from Eu2+to Eu3+and Sm3+becomes in evidence with incrasing the content of Sm2O3. Moreover, heat treatment increases the conversion of Eu3+to Eu2+, resulting in enhancement of Eu2+ions emission intensity in the Eu doped aluminosilicate glasses.(2) Tb/Sm codoped oxyfluoride aluminosilicate glasses and glass-ceramics have been prepared by the melt-quenching method and subsequent heat treatment. Occurrence of the self-quech effect of Sm3+ions and the energy transfer from Tb3+to Sm3+in the glasses have also been experimentally corroborated. The Tb/Sm codoped luminescent glasses exhibits the warm white light emission. The heat treatment increases the rare earth ions emission intensity and fluorescent lifetime in the Tb/Sm doped oxyfluoride aluminosilicate glasses.