高亮度β-sialon∶Eu^(2+)绿色荧光粉的合成及其在高色域白光LED上的应用

Synthesis of the highly efficient β-sialon∶Eu^(2+) green phosphor and its application in wide-color gamut white LEDs

采用高温固相法在1 800~1 950℃/0.9 MPa N2条件下合成了不同z值的Si6-zAlzOzN8-z∶Eu^(2+)(0<z≤4.2)(即β-sialon∶Eu^(2+))绿色荧光粉。随着z的增加,荧光粉的发光光谱发生红移,荧光强度增强;但当z值较大时,Eu^(2+)更容易进入杂质相,从而导致其荧光强度开始下降。此外,原料对发光影响较大。使用自制硅铕合金粉和高纯微米级硅粉氮化而得的氮化硅,比使用Eu2O3作为铕源或商业Si3N4合成的荧光强度更高,同时发射峰位蓝移。在450nm激发下,β-sialon∶Eu^(2+)的吸收率和外量子效率最高分别可达70.1%和49.0%。采用蓝光芯片,使用β-sialon∶Eu^(2+)(z=0.1)搭配红色KSF∶Mn4+进行封装,在120mA驱动电流下,获得了色温为6 504K、光通量为41.63lm、光效为112.47lm/W、理论色域为95.40%NTSC的白光LED(WLED)。这些结果都表明β-sialon∶Eu^(2+)绿色荧光粉在高色域白光LED中具有优势明显的潜力。

Si6-zAlzOzN8-z∶Eu（2＋）（0z≤4.2）（β-sialon∶Eu（2＋））with different z values was synthesized by the solid-state reaction at 1 800-1 950 ℃in a 0.9 MPa nitrogen atmosphere.As the z value increases,the photoluminescence spectrum presents the red-shift and the photoluminescence intensity goes up.However,the emission intensity ofβ-sialon∶Eu（2＋）declines when the z value further increases because Eu（2＋）is more likely accommodated into the impurities.The raw materials also have an influence on the emission intensity.Compared to thoseβ-sialon∶Eu（2＋）synthesized by using Eu_2O_3 and commercially available Si3 N4,β-sialon∶Eu（2＋）made from the laboratory-made Si-Eu alloy and Si3 N4（via nitridation of high purity silicon）has a higher photoluminescence intensity.Under 450 nm excitation,the maximum absorption and external quantum efficiencies ofβ-sialon∶Eu（2＋）are 70.1% and 49.0%,respectively.White LEDs（WLED）fabricated by usingβ-sialon∶0.01 Eu（2＋）（z=0.1）,red-emitting KSF∶Mn4＋and a blue LED chip exhibit a theoretical color gamut of 95.40%of NTSC,color temperature of 6 504 K,luminous efficacy of 112.47 lm/W when driven at 120 mA current,indicating the great potential of#-sialon∶Eu（2＋）for use in backlights.