Preparation And Properties Of Rare Earth Doped Ba₃Lu₄O₉ Luminescent Materials

White light-emitting diodes(W-LEDs)plays an important role in lighting and display field because of its energy saving,environmental protection,long life and high luminous efficiency.The phosphor is the key to improve the luminous performance.Oxide phosphors have excellent properties such as high efficiency,chemical stability and non-toxicity,so they are considered to be a promising luminescent material.In this thesis,based on Ba₃Lu₄O₉system,green and red phosphors for W-LEDs were obtained by doping single ion and energy transfer process between sensitizers and activators.The findings are as follows:(1)Tb³⁺-doped Ba₃Lu₄O₉green phosphors were synthesized by high-temperature solid-phase method.The results showed that Tb³⁺was successfully introduced into Ba₃Lu₄O₉without obvious impurities.Under the excitation of 266 nm,green luminescence with good monochromatic property was emitted when the concentration of Tb³⁺was 1 mol%.At this doping concentration,the green luminescence of the sample is the strongest,and the corresponding color coordinate is(0.3054,0.5569),which is close to the standard green color coordinate.(2)A new type of orange-red Ba₃Lu₄O₉:Sm³⁺phosphor was prepared by high-temperature solid-state method.Through the analysis of the structure and optical properties of Ba₃Lu₄O₉:Sm³⁺phosphor,it is determined that the concentration quenching occurs when the doping concentration is 2 mol%,and the mechanism is attributed to the dipole-dipole interaction.The luminescence intensity at 150 ^oC is 79.4%of that at room temperature,and it has good thermal stability.The chromaticity coordinates are located in the orange-red region.The results show that Ba₃Lu₄O₉:Sm³⁺phosphor is a promising orange-red phosphor.(3)Through the high-temperature solid-state reaction,Sm³⁺and Eu³⁺co-doped Ba₃Lu₄O₉red phosphors was prepared in air.By adjusting the concentration ratio of Sm³⁺and Eu³⁺,the effective excitation spectral range of the phosphor can be broadened.The results prove that the sensitizer Sm³⁺transfers energy to the activator Eu³⁺through the electric dipole-quadrupole interaction,and the phosphor has good thermal stability.Ba₃Lu₄O₉:Sm³⁺,Eu³⁺is a potential red phosphor for white light-emitting diodes.(4)A multi-color luminescent phosphor Ba₃Lu₄O₉:Tb³⁺,Eu³⁺was synthesized via With the increase of Eu³⁺concentration,adjusting the energy transfer process between Tb-Eu,the transformation of the tunable color of phosphor from green(0.3057,0.5623)to orange(0.6108,0.3462)was realized.The phosphor can be used as a multi-color component for solid-state lighting.