Preparation And Properties Of Rare Earth Ions Doped Luminescence Glasses

Rare earth ions doped luminescence glass has a wide range of applications in optoelectronics field, such as laser, optical amplifiers, optical communications, energy storage and display. Oxyfluoride glass has many advantages, including high mechanical strength, excellent chemical stability and thermal stability of oxide glass and lower phonon energy of fluoride glass, which can effectively enhance the luminescence intensity of the doped RE ions. The present paper take Sm3+, Dy3+, Ce3+and Tb3+doped SiO2-Al2O3-LiF-CaF2oxyfluoride glass as the research object, its composition and preparation process, as well as the effect of heat treatment on the performance of oxyfluoride glass has been studied in detail, and the relationship between glass composition, structure, and luminescent properties has been explored.Through substantive experimental work, some new and interesting results have been obtained and listed as follows.The structure, thermal stability, and absorption or transmittance performance of Sm3+, Dy3+, Ce3+and Tb3+doped SiO2-Al2O3-LiF-CaF2oxyfluoride glass have been investigated. The results indicated that the network of these oxyfluoride luminescent glasses is composed mainly of [SiO4] and [AlO4] tetrahedrals, which linking by vertex angle oxide ions. Li+, Ca2+and/or the RE ions are in the network gap, Al3+ions mainly as the glass network former enter in the network with [AlO4] tetrahedrals, part F-ions substitute for O2-ions to enter in the network, and another part located at the network gap. The glass stability factors all greater than100, indicating that these oxyfluoride luminescent glasses have good thermal stability, and the glass Hruby constants indicated that they have certain anti-crystallization ability. The Sm3+, Dy3+single doped SiO2-Al2O3-LiF-CaF2oxyfluoride glass has a good absorption property in the UV-vis-NIR region, whereas Ce3+, Tb3+ions single doped or codoped oxyfluoride glass has a good light transmittance performance in the visible region, and the UV absorption edge is shorter, which is advantageous for the transmission of emission light. The effect of heat treatment on the structure and properties of SiO2-Al2O3-LiF-CaF2oxyfluoride glass-ceramic has been investigated. The crystallization treatment has been carried out on the as-made glass, the crystallization activation energy and crystallization index have been calculated, and the crystallization mechanism has been analyzed. The results indicated that it can be obtain an ideal only containing CaF2nanocrystalline transparent glass-ceramic by controlled the crystallization temperature within the range of670-690℃, and the holding time of2hours. Compare to the as-made glass, the RE ions in glass-ceramic exhibit greater intensity fluorescence under UV excitation.The luminescent property of Sm3+or Dy3+doped SiO2-Al2O3-LiF-CaF2oxyfluoride glass has been investigated. The Sm3+doped SiO2-Al2O3-LiF-CaF2oxyfluoride glass emits intense orange light under UV excitation, and the luminescent intensity first increases and then decreases with the optimal Sm3+concentration of1.0mol%. The luminescence decay time of Sm3+is of milliseconds magnitude, with the Sm3+increasing concentration decreases. The main energy transfer mechanism between Sm3+-Sm3+ions is the dipole-dipole interaction. The blue light-emitting4F9/2→6H15/2(482nm) of Dy3+ions doped SiO2-Al2O3-LiF-CaF2oxyfluoride glass is stronger than the intensity of yellow light-emitting4F9/2→6H13/2(574nm) under UV excitation, and becomes the strongest emission. Thus, the Dy3+ions doped oxyfluoride luminescent glass providing a unique and more efficient material matrix for the solid-state laser and fiber amplifier. The luminescent intensity of Dy3+ions doped oxyfluoride luminescent glass first increases and then decreases with the optimal Dy3+concentration of0.5mol%. The luminescence decay time of Dy3+is of milliseconds magnitude, and with the Dy3+increasing concentration decreases. The main energy transfer mechanism between Dy3+-Dy3+ions is the dipole-dipole interaction.The Ce3+doped SiO2-Al2O3-LiF-CaF2oxyfluoride glass emits intense purplish-blue light under UV excitation, luminescence centers at385nm with the luminescence decay time of the order of nanoseconds. The Tb3+doped SiO2-Al2O3-LiF-CaF2oxyfluoride glass mainly emits the green emissions5D4→7FJ(J=6-3). Of them, the relative intensity of 543nm (5D4→7F5) green emission is above2.5times than other emissions. It is very significant that Tb3+can be doped up to8.0mol%in host glass without concentration quenching. This indicates that the as-made host glass provides a more homogeneous environment, and enhances the distribution of RE ions. The good distribution of RE ions could reduce the non-radiative relaxation, and result in an increase in the emission intensity and quenching concentration. Therefore, the as-made Tb3+doped oxyfluoride luminescent glass has important potential applications in the high-density green laser and short fiber amplifier. Ce3+/Tb3+codoped SiO2-Al2O3-LiF-CaF2oxyfluoride glass mainly exhibits the green emission of Tb3+ions (peak at543nm) under UV excitation. The Ce3+→Tb3+effective energy transfer were observed in Ce3+/Tb3+codoped oxyfluoride luminescent glass, resulting in the luminescent intensity of Tb3+enhances above10times than that of the same Tb3+concentration single doped oxyfluoride glass. It was also observed that the luminescent intensity of Tb3+in Ce3+/Tb3+codoped oxyfluoride luminescent glass increases firstly and then decreases with the increasing Ce3+ions concentration. The main resonance energy transfer mechanism between Ce+-Tb3+ions is the dipole-dipole interaction.