Luminescent Properties Of Rare Earth(Ce³⁺/Tb³⁺/Sm³⁺)doped Glass Ceramics Containing YPO₄ Nanocrystals

Today,the method of doping rare earth in glass-ceramic has become one of the most popular research trends in the preparation of new optical solid materials.The glass-ceramic combines the advantage of both the glasses and crystals.Compared with the higher cost of crystal materials,glass-ceramic is easy to be produced in large quantities and cost little time,which makes it a substitute for traditional light functional material.With the rapid development of glass-ceramic,rare earth doped glass-ceramic also used in the field of white LEDs attributed to its excellent light-emitting properties.At present,commercial W-LEDs can be realized by combining blue chips with a yellow-emitting phosphor into white light emission,but the red color in the phosphor is missing,which results in a relatively low color rendering index.Using near ultraviolet LED plus RGB three-color phosphor is theoretically possible to obtain any color temperature and high color rendering index white LEDs.But this technology has not matured and caused serious loss of light output.Therefore,the study of rare earth ion doped glass-ceramic for white LEDs materials has received wide attention.The main contents of this paper are to study the rare earth ions(Ce³⁺,Tb³⁺ and Sm³⁺)single doped and co-doped YPO₄ glass-ceramic material,we have analyzed the spectral characteristics of Ce³⁺,Tb³⁺ and Sm³⁺ ions doped with YPO₄ glass-ceramic,the corresponding excitation spectra and emission spectra and the fluorescence lifetime at different ions doping concentrations.The color rendering index of YPO₄ microcrystals with different concentrations of ions was analyzed,and its application in white LEDs was discussed.The glass-ceramic were prepared by the melt-quenching method and then the precursor glasses were annealed and heat-treated to prepare different rare earth doped YPO₄ glass ceramics specimens.The XRD and TEM images of the samples showed that the existence of YPO 4 nanocrystals in glass ceramics,and the UV-visible light transmittance of the samples after microcrystallization treatment was over 80%.Regardless of the uncontrolled accidental conditions in the experiment,such as precision instruments?environmental temperature,the excitation spectra and emission spectra of the samples showed that the luminescent properties of Ce³⁺/ Tb³⁺,Tb³⁺/ Sm³⁺ ions co-doped YPO₄ glass-ceramics have been enhanced in different degrees.We also discussed the energy transfer process between Ce³⁺/Tb³⁺ ions and Tb³⁺/Sm³⁺ ions.Blue,green and red luminescence bands can be monitored in the emission spectrum of the samples,the calculated color coordinates of the samples are located in the white light area,which shows that YPO₄ crystallized glass can produce white light emitting under the excitation of ultraviolet light after the in-corporation of rare earth ions(Ce³⁺/Tb³⁺,Tb³⁺/Sm³⁺),which is a potential white LED light-emitting diodes matrix material.