燃烧法制备(Ca1-xSrx)S:Eu2+红色荧光粉的发光性能研究

利用硝酸盐和含硫燃烧剂硫脲(CH4N2S)的氧化还原反应,通过燃烧法在较低的起始温度(500～550 ℃)下合成了白光LED用红色荧光粉(Ca1-xSrx)S:Eu2+,并研究了实验过程中各种实验条件对其发光性能的影响.XRD图像表明不同物质的量比的Sr与Ca合成的荧光粉均为立方相的(Ca1-xSrx)S:Eu2+.SEM图像表明燃烧法合成的(Ca1-xSrx)S:Eu2+的晶体粒径为微米量级,且颗粒均匀.当n(Sr)∶n(Ca)=1时,它的激发谱为1个覆盖430～500 nm的宽带,发射谱为峰值位于624 nm的宽带.当Eu2+的摩尔分数为0.008时,发光强度达到最大值.所得前驱物在1 100 ℃的马弗炉中退火5 h,发光强度与结晶度将进一步提高.与高温固相法相比,激发光谱与发射光谱没有明显变化,燃烧法生成物分散性好,反应初始温度比较低(500 ℃左右),反应时间短(10 min左右).反应所用的硫脲价格低廉,反应速度快,是一种实用的燃烧剂.

Study on the Luminescent Properties of (Ca1-xSrx)S:Eu2+ Phosphor Formed by Combustion

A red phosphor(Ca1-xSrx)S: Eu2+ was synthesized by combustion method with ignition temperature of 500～550 ℃ using oxidation-reduction reaction of the mixed metal nitrate.The effect of experimental conditions on its luminescent properties was studied.XRD patterns of samples synthesized with different ration of Sr and Ca show that all of them belong to cubic phase.SEM image indicates that the uniform crystal grain of the(Ca1-xSrx)S: Eu2+ prepared by combustion is in micro level.The excitation spectrum is composed of two broad band covered 300～500 nm and emission spectrum makes up of only one broad band that the peak locate at 624 nm when n(Sr)∶n(Ca)=1.The luminescent intensity will reach the maximum when the mole fraction of Eu2+ is 0.008.The luminescent intensity and the crystallinity will enhance if the precursor is sintered at 1 100 ℃ for 5 h in a muffle furnace.Comparing with the solid-state method,the combustion method uses less time;Lower temperature and the emission spectrum has little change.Sulfourea used in the experiment is an applied reducer for its lower price and fast reactionary speed.