白光LED用碱土金属硅酸盐荧光粉的光谱性质

Spectral Properties of Alkaline Earth Composite Silicate Phosphors for White-LED

采用固相法合成了A:(SrBa)3SiO5:0.024Ce3+,0.024Li+;B:Sr2.73M0.2SiO5:0.07Eu2+(M=Ba,Mg,Ca);C:(SrBa)3SiO5:xEu2+三个系列的硅酸盐荧光粉。测量了它们的激发光谱和发射光谱。Ce3+激活的硅酸盐荧光粉(A系列)有351,418nm两个激发峰,418nm这个峰较强。随着Ba离子含量的增加,发射光谱峰值波长出现了红移。因此,改变Ba离子的含量,可以改变荧光粉的发射峰值波长,进而调整白光LED的色坐标和显色指数等指标。Eu2+激活的硅酸盐荧光粉(B,C系列)激发光谱是从350～450nm的宽带激发。Ce3+激活的荧光粉发射峰波长要比Eu2+激活的短,在540～555nm左右,而Eu2+激活的发射峰波长在570～583nm范围。在Sr2.73M0.2SiO5:0.07Eu2+系列(B)中,M取Ba时效果较好。在(SrBa)3SiO5:xEu2+系列(C)中,x取不同值发射光谱的峰值波长和半峰全宽有所变化,但是变化的规律不是很明显。用这两种元素作为激活剂的硅酸盐荧光粉均比较适合用于近紫外、紫外和蓝光芯片封装白光LED。在Sr3SiO5:Ce3+,Li+和Sr3SiO5:Eu2+中掺入Ba可以使发射峰红移。

Three series silicate phosphors （A： （SrBa）3SiO5 ： 0. 024Ce^3＋ , 0. 024Li^＋ ; B： Sr2.73M0.2 SiO5： 0.07 Eu^2＋ （ M = Ba, Mg, Ca） ; C ： （SrBa） 3 SiO5： xEu^2＋ ） were synthesized by solid reaction method. Their excitation and emission spectra were measured. There are two exitation peaks （351 nm and 418 nm, 418 nm is stronger） for Ce^3＋ -activated （Series A） silicate phosphors. With increasing the content of Ba ion, their emission peaks change to longer Wavelength. Consequently, we can change its color then at the end adjust the CIE chromaticity and color rendering index of white-LED. Eu^2＋ -activated （Series B and C ） silicate phosphors have broad excitation bands from 350 nm to 450 nm. The emission peaks of Ce^3 ＋-activated silicate phosphors are 540 - 555 nm and shorter than Eu^2＋ -activated silicate phosphors , while the emission peaks of Eu^2＋ -activated silicate phosphors are at 570-583 nm. For the series B（SrE.73M0.2SiO5： 0.07Eu^2＋ （M = Ba,Mg,Ca））, it＇s better when M = Ba. At the series C（ （SrBa）3SiOs： xEu^2＋ ）, their emission peaks and FWHM change with no obvious rule. The emission peaks of Ba-doped Sr3 SiO5 ： Ce^3＋ , Li^＋ and Sr3 SiO5 ： Eu^2 ＋ shifted to longer wavelength. Both of them can be used for packaging white-LED with NUV＇ UV and blue LED chip.