【摘要】 采用化学共沉淀法合成具有Tb、Gd稀土掺杂的Y3Al5O12∶Ce3+荧光粉,通过XRD和荧光光谱研究其晶体结构和光致发光。结果表明,(Y2.95-xTbx)Al5O12∶Ce3+和(Y2.95-xGdx)Al5O12∶Ce3+系列荧光粉具有与Y3Al5O12∶Ce3+相同的石榴石晶体结构,但晶胞参数随Tb、Gd取代Y而略有增加;随Tb、Gd掺杂量增加,荧光粉发射波长逐渐红移,当x=2.95时,发射波长λmax分别从532nm红移至551和542nm;根据晶体场理论解释了荧光粉发射波长红移现象。这种发射波长红移的荧光粉能够显著地增强蓝光LED芯片与荧光粉组合形成的白光中红光成分,进而改善白光LED光源质量。更多还原

【Abstract】 (Y3-x-yREx)Al5O12∶Cey(RE=Tb,Gd) phosphors were synthesized by coprecipitation method.The crystal structures and luminescence properties of(Y3-x-yREx)Al5O12∶Cey phosphors have been investigated by means of XRD and photoluminescent excitation and emission spectra.(Y2.95-xTbx)Al5O12∶Ce3+ and(Y2.95-xGdx)Al5O12∶Ce3+ have the same crystal structure which is garnet with a different lattice parameter.Substitution by Tb3+ or Gd3+ ions in the Y3+ sites will red shift the emission light of the phosphor.The mechanism of modulation of the emission wavelength in the phosphor was explained by variation in crystal field.Since emission band shifts to a longer wavelength,white LED using blue emitting LEDs and(Y3-x-yREx)Al5O12∶Cey phosphor can overcome weak red emission intensity of that using blue emitting LEDs and YAG∶Ce phosphor.In the case of using(Y3-x-yREx)Al5O12∶Cey phosphor to fabricate white LED,we can expect better white emitting light source for illumination.更多还原