The Modification Of Luminescence Of Phosphors/glasses Applied In LED

Recently,luminescent materials doped with rare earth(Tb³⁺,Eu³⁺,Ce³⁺,etc.)or other luminescent(Bi³⁺,Cu⁺,Mn⁴⁺,etc.)ions have attracted more and more attention,such as phosphors and transparent fluorescent glasses.These two kinds of materials show prominent chemical,physical stabilities,and good thermal stability,which have been extensively studied for luminescent ions doping.The commercial way to get W-LEDs is coating the yellow phosphors on blue chips?460 nm?.In order to improve correlated color temperatures and color-rendering index,W-LEDs achieved through coating the single-phase phosphors or glasses on near-ultraviolet chips?365-405 nm?have been investigated deeply.Therefore, it is of great significance to find a single-phased phosphor or transparent glass that can realize white emission under the excitation of near-ultraviolet light.The main work of this article is as follows.1.Single-phase Y₂BaAl₄SiO₁₂:Tb³⁺,Eu³⁺phosphors with adjustable luminescence were successfully prepared by high-temperature solid-state reaction method.The structural,luminescent properties and energy transfer?ET?process of Y₂BaAl₄SiO₁₂:Tb³⁺,Eu³⁺phosphors were systematically analyzed with the help of the X-ray diffraction?XRD?,scanning electron microscopy?SEM?,excitation spectra,emission spectra and photoluminescence decay curves.Tunable luminescence ranging from green to yellow and eventually to red can be achieved by elevating amounts of Eu³⁺ions in Tb³⁺,Eu³⁺co-doped samples.Besides,the ET mechanism and efficiency were also analyzed.The maximum ET efficiency was 67%.All the results show that Y₂BaAl₄SiO₁₂:Tb³⁺,Eu³⁺phosphors can be used in solid-state lighting.2.Various Cu⁺doped transparent aluminosilicate glasses were synthesized by melt quenching method.Their structural and luminescent properties were studied systematically by XRD,ultraviolet-visible transmission spectra,photoluminescent spectra and fluorescence decay curves.By increasing optical basicities of these glasses,excitation peak of Cu⁺shifted from 300 to 321 nm and emission peak shifted from 445 to 536 nm.On this basis,longer excitation wavelength?330 nm?and emission wavelength?545 nm?were achieved as the amount of Cu⁺was increasing.More importantly,these Cu⁺doped glasses show high external quantum yields?35.8-57.4%?and good thermal stability.Our research may provide a new strategy for extending the practical application of Cu⁺doped transparent luminescent glasses.