Preparation And Properties Of Luminescent Glass And Glass-ceramic For High-power White LED/LD

State-of-the-art WLED technology is rapidly developing towards high-power（≥1 W）to meet the increasing demand of high-brightness lighting in auto headlight,general lighting,projection display and so on.However,traditional organic packaging materials have low thermal conductivity,which can not transfer the heat generated by the chip in time,giving rise to serious heat accumulation.Because of its poor thermal stability,it is liable to aging and yellowing when operating at high temperature,which deteriorates the luminous efficiency.Luminescent glass and glass-ceramic have good thermal properties and are expected to remedy the problem of heat accumulation in high-power applications.At present,the properties of glass and glass-ceramic still has area for improvement.Luminescent glass has weak absorption and low luminous intensity,and it is difficult for glass-ceramic to make all active ions enter the crystal lattice.In addition,the white light scheme of blue+yellow has low CRI and high CCT.The research results of this paper are as follows:（1）To supplement the red component,a tunable Tm³⁺and Mn²⁺co-doped fluorosilicate glass was prepared.Tm³⁺ions emit blue light,Mn²⁺ions emit green and red light.The good transmittance（～90%）of glass matrix in visible range contributes to improve the quantum efficiency.Through changing the content of Y₂O₃,the relative intensity of red and green of Mn²⁺ions can be adjusted.When Y₂O₃ content is 4mol%,the CCT of the sample is 3600 K.In terms of thermal properties,good thermal conductivity(2.17 W·m^-1·K^-1,100℃)is conducive to rapid heat dissipation,and the increasing Y₂O₃ can improve heat quenching performance.When the content of Y₂O₃ is 0 mol%and4 mol%,the corresponding thermal activation energy is 0.184 e V and 0.206 e V,respectively.（2）To maximize the utilization of active ions in glass-ceramic and enhance the luminescence intensity in glass,a Tm³⁺,Eu²⁺,Eu³⁺tri-doped fluorosilicate glass ceramics was prepared.Tm³⁺ions emit blue light in glass phase,Eu ions can play different roles in glass or Ba Si₂O₅ crystal phase.During the heat treatment,part of Eu³⁺ions successfully enter the lattice and they will be self-reduced to Eu²⁺and emit green light,while the remaining Eu³⁺ions stay in glass phase and emit red light.After heat treatment of 660℃、5h+780℃、1h,the sample with color coordinate（CIE）of（0.3813,0.3783）,CCT of 3986 K,CRI of 91 was obtained.The luminescence intensity in glass is increased by more than 212%due to the presence of microcrystals which enhances the scattering.As for the thermal stability,at 100℃,the blue emission intensity of Tm³⁺ions only decrease by 6%,the red intensity of Eu³⁺ions is still 90%of original intensity,and the performance of Eu²⁺ions in Ba Si₂O₅is weaker.Fortunately,the good thermal conductivity(2.69 W·m^-1·k^-1,100℃)can keep the device at a low temperature,effectively alleviate heat quenching.（3）To decrease the dosage of rare earth ions,an Eu doped fluorosilicate glass ceramic was prepared.By the self-reduction mechanism,Eu³⁺ions emit red light in glass phase and Eu²⁺ions emit green and blue light in Ba Mg Si O₄ crystal phase.Through heat treatment at 670℃for 4h,800℃for1h,the glass-ceramic sample with CIE of（0.3677,0.4073）,CCT of 4500 K and CRI of 80 was obtained.The precipitations of microcrystals have a positive impact on the luminescence of glass,and the emission intensity of Eu³⁺in glass is enhanced by 279%.The growth of ordered structure in glass also improves the thermal conductivity from 1.96 W·m^-1·k^-1 to 2.58 W·m^-1·k^-1.