Study On The Luminescence Properties And Energy Transfer Of Rare Earth/transition Metal Ions Doped SrO-MgO-B₂O₃ Glasses

Light Emitting Diodes（LEDs）have gradually replaced traditional light sources by virtue of their high efficiency,environmental protection and energy saving.The current commercial white LED（WLED）and plant growth LED are mainly composed of specific wavelength phosphors and blue chips or UV chips,but this phosphor converted LED（pc-LED）has organic resin yellowing and aging,uneven luminescence,epoxy resin heat resistance and other disadvantages.And luminescent glass has the advantages of uniform luminescence,high thermal stability,and easy encapsulation.Therefore,we studied the luminescence properties and energy transfer of rare earth/transition metal ions doped luminescent glass to provide basic theory and technical support to promote the preparation and application of high-performance luminescent glass.By using the traditional high temperature melt-quenching technique,a number of Eu²⁺/Mn²⁺,Tm³⁺/Dy³⁺,and Ce³⁺/Mn²⁺co-doped borate glasses were prepared.The as-prepared luminescent glasses were systematically investigated using X-ray diffraction,absorption spectra,excitation/emission spectra,fluorescence lifetimes,and color coordinates.For Eu²⁺/Mn²⁺co-doped SrO-MgO-B₂O₃ glasses,continuous tunable emission from blue to cold white to warm white light can be achieved by fixing the Eu²⁺content and changing the Mn²⁺doping content.It is demonstrated that Eu²⁺transfers energy to Mn²⁺through the mechanism of dipole-dipole interaction.In addition,the simply assembled WLED lamp exhibits near-standard white light with color coordinates of（0.3345,0.3091）and correlated color temperature of 5369 K under a current drive of20 m A.These results indicate that Eu²⁺/Mn²⁺co-doped SrO-MgO-B₂O₃ glasses have a strong potential for practical applications in full-spectrum emitting WLEDs.In the study of Tm³⁺/Dy³⁺single-and co-doped SrO-MgO-B₂O₃ glasses,the existence of energy transfer between Tm³⁺and Dy³⁺was confirmed by emission spectra and fluorescence lifetimes.Through the photoluminescence excitation spectra,it can be confirmed that both Tm³⁺/Dy³⁺single-doped and co-doped SrO-MgO-B₂O₃ glasses can be efficiently excited by near-UV light.Tunable emission from blue to cool white and finally to warm white light can be achieved for Tm³⁺/Dy³⁺co-doped glasses under excitation at 352,362 and 365 nm.Furthermore,by using the Inokuti Hirayama（I-H）model,it is demonstrated that the energy transfer in the Tm³⁺-Dy³⁺cluster proceeds through a dipole-dipole（d-d）interaction mechanism.In addition,the thermal stability of Tm³⁺/Dy³⁺co-doped SMB glasses was verified by temperature-dependent spectra.For Ce³⁺/Mn²⁺co-doped SrO-MgO-B₂O₃ luminescent glasses,the emission color can be adjusted by changing the doping concentration of Mn²⁺and the position of the color coordinate gradually moves from the blue region to the red region as the Mn²⁺concentration increases.In Ce³⁺/Mn²⁺co-doped SrO-MgO-B₂O₃ glasses,the energy transfer was shown to be from Ce³⁺to Mn²⁺by dipole-dipole interaction.The emission spectra of Ce³⁺/Mn²⁺co-doped SrO-MgO-B₂O₃ glasses consists mainly of blue and red emission bands,which has a good match with the absorption spectrum of plant pigments,which indicates that Ce³⁺/Mn²⁺co-doped SrO-MgO-B₂O₃ luminescent glasses can be applied to plant growth LED.