Design,Elaboration And Optical Properties Of Rare Earth Doped Fluoride Oxide Glass And Glass Ceramics

This thesis is focused on the preparation and optical properties of rare earth doped fluoride oxide glass and glass ceramics.The thesis mainly includes three parts:?a?Highly transparent cerium doped glasses with full-band UV-shielding capacity?Chapter2?;?b?Intense Luminescence in Terbium-activated Ba_0.84Gd_0.16F_2.16 oxyfluoride scintillating glass ceramics?Chapter 3?;?c?Tunable white light and energy transfer of Eu²⁺-Tb³⁺-Eu³⁺tri-activated glasses synthesized in air?Chapter 4?.The main contents are listed as follows,?a?Highly transparent cerium doped glasses with full-band UV-shielding capacity.With thinning ozone layer,considerable attention has been paid to developing materials that block or reduce ultraviolet?UV?transmission.Here,bulk cerium doped glasses with relatively high transparency were successfully manufactured via the melt quenching method.The varied ratio of Ce³⁺and Ce⁴⁺in glasses could be deduced by optical properties in photoluminescence excitation,emission spectra,decay curves and absorption spectra.These glasses exhibit excellent UV-blocking capacity due to the absorption of Ce³⁺and Ce⁴⁺.And their outstanding physical and chemical stability have been demonstrated in the condition of high temperature,long-term UV radiation,strong alkali solution and acetone.Hence,our cerium doped glasses are potentially attractive candidates in UV-shielding device.?b?Intense Luminescence in Terbium-activated Ba_0.84Gd_0.16F_2.16 oxyfluoride scintillating glass ceramics.Starving for the excellent radiation detection materials in broad applications,extensive research on scintillators was promoted rapidly.However,the high coast,time-consuming fabrication process and insufficient radioluminescence of conventional scintillators limits the practical application.Here,we report an efficient and transparent Tb³⁺-doped Ba_0.84Gd_0.16F_2.16 glass ceramic?GC?prepared via thermal treatment technology.The mean size and volume fraction of nanocrystal in GC were determined via XRD patterns.The structure model was elaborated by molecular dynamics simulations to have a deeper look into the phase separation process.Consistent with the theoretical simulation,the PL efficiency was increased to 61%in GC.Even better,the enhanced XEL intensity reaches 194%of that of commercial BGO scintillator since the efficient absorption of X-ray,high transparency and low phonon environment.Our results suggests that Ba_0.84Gd_0.16F_2.16:Tb³⁺GC has potential application in X-ray detection.?c?Tunable white light and energy transfer of Eu²⁺-Tb³⁺-Eu³⁺tri-activated glasses synthesized in air.An ever increasing demand for white light-emitting diodes?W-LEDs?results in the gradual growth of research on functionalized luminescent glasses.In this work,single-composition tunable white-emitting Eu²⁺-Tb³⁺-Eu³⁺tri-activated glasses were synthesized by melt quenching method without additional reducing atmosphere.The coexistence of Eu²⁺and Eu³⁺was confirmed.Tb³⁺can act as bridge to connect Eu²⁺-Eu³⁺luminescent centers by energy transfer.Tone-tunable white light can be achieved by coupling the emission centered at 412,541,and 612 nm contributed from Eu²⁺,Tb³⁺and Eu³⁺,respectively.By adjusting the relative content of Eu²⁺/Tb³⁺/Eu³⁺,ideal chromaticity coordinates of?0.33,0.33?can be achieved under excitation of ultraviolet light.High thermal stability and tiny chromaticity shift were exhibited in samples.These results suggest that Eu²⁺-Tb³⁺-Eu³⁺tri-activated glasses have great potential application in ultraviolet-driven W-LEDs.