毕业论文移动版

摘 要： 本文采用高温固相法合成一系列以正磷酸盐为基质的荧光粉材料，并研究了其发光性质以及在白光LED照明方面的应用。主要做了以下工作：

（1）制备了Ca10K(PO4)7:Eu2+, Sr2+, Mg2+ (CKP:Eu2+, Sr2+, Mg2+)荧光粉，并研究了它们在近紫外光激发下的发光性质。研究发现：Eu2+激活的CKP在425-650 nm范围内呈现出一个不对称的发射带，这是由此荧光粉中含多个Eu2+发射中心导致的；相应的激发光谱表现出一个宽的激发带，可以很好地和近紫外LED芯片相配合。当在CKP:Eu2+材料中引入Sr2+和Mg2+后，实现了从浅蓝色到黄绿色范围内一系列颜色可调节的发光，这主要归因于Sr2+和Mg2+对CKP基质结构的影响。研究结果表明制备的CKP:Eu2+, Sr2+, Mg2+荧光粉在白光LED方面具有潜在的应用价值。93221

（2）制备了 (Sr0。86Mg0。14)3(PO4)2:Eu2+, Mn2+(SMP:Eu2+,Mn2+)荧光粉，并研究它们在近紫外光激发下的发光性质。对于Eu2+掺杂的SMP样品，两个主要的发射带在522nm和625nm处，归属于Eu2+不同的发光中心，采用激发光谱和时间分辨荧光光谱证实了这点。在SMP基质中，Eu2+的最佳掺杂浓度为0。2%。SMP:0。2%Eu2+激发光谱在250-450nm范围内呈现一个宽的发射带，可以很好地和近紫外LED芯片相配合。当Mn2+离子掺杂到SMP:0。2%Eu2+荧光粉后，Eu2+的发光强度在522 nm处出现快速衰退，这是由于Eu2+ 到Mn2+发生了能量传递，衰减寿命的变化可以解释这个过程。

（3）为了评估开发的荧光粉在LED照明方面的应用潜力，选取了两种荧光粉材料进行组合，经测试，在365nm激发下CKP:0。007Eu2+,0。03Mg2+荧光粉与SMP:0。2%Eu2+,20%Mn2+荧光粉复合后的相关色温为4738 K，色坐标为(0。357, 0。389)，因此，实现了暖白光发射。

毕业论文关键词：稀土发光材料，磷酸盐，白光LEDs，发光性质

Abstract: A series of phosphate-based phosphors were synthesized by the solid-state reaction method and their optical properties as well as the application in white light-emitting diodes (LEDs) were investigated。 The main research contents are listed as follows:

(1) The Ca10K(PO4)7:Eu2+,Sr2+,Mg2+ (CKP:Eu2+,Sr2+,Mg2+) phosphors were prepared and their photoluminescence properties under near-ultraviolet excitation were studied。 Research indicates: Eu2+-activated CKP shows an asymmetrical emission band in the range of 425–650 nm, derived from various Eu2+ emission centers。 The corresponding excitation spectrum presents a broad excitation band which can match well with the emission wavelength of the near ultraviolet LED chip。 By introducing Sr2+ and Mg2+ into CKP:Eu2+, tunable emission has been realized from light blue to greenish yellow including white, which is mainly owing to the effect of Sr2+ and Mg2+ on the structure of CKP。 The above investigation results reveal that the CKP:Eu2+,Sr2+,Mg2+ phosphors have potential applications in white LEDs。 

(2) The (Sr0。86Mg0。14)3(PO4)2:Eu2+,Mn2+ (SMP:Eu2+,Mn2+) phosphors were prepared and their photoluminescence properties under near-ultraviolet excitation were investigated。 For Eu2+-single-doped SMP samples, two main emission bands located at 522 and 625 nm were found which could be attributed to different Eu2+ emission centers, and the excitation spectra as well as time-resolved photoluminescence spectra also verify this point。 The optimal Eu2+ concentration in the SMP host was determined to be 0。2%。 The excitation spectra of the typical SMP:0。2%Eu2+ reveal that broad excitation bands from 250 to 450 nm have been obtained, which can well match the NUV LED chip。 By doping Mn2+ ions into the SMP:0。2%Eu2+ phosphor, the emission intensity of Eu2+ at 522 nm shows a fast decay owing to the energy transfer (ET) from Eu2+ to Mn2+, which could be interpreted by the change of the decay lifetimes。