【作者】 赵昕冉；

【导师】 傅仁利；

【作者基本信息】 南京航空航天大学 ， 材料学， 2010， 硕士

【摘要】 本论文研究了CaSi₂O₂N₂:Eu²⁺的制备工艺和Ca_1-xEu_xSi₂O_-δN2+2/3δ（δ=0、1）荧光粉的荧光性能,对CaSi₂O₂N₂:Eu²⁺的红移现象进行了深入探讨;采用HF酸处理对CaSi₂O₂N₂:Eu²⁺微观形貌和荧光性能进行了改进;合成了CaSi₂O₂N₂:(Eu²⁺/Ce³⁺)荧光粉,研究了其荧光性能和Ce³⁺→Eu²⁺的能量传递。实验结果和计算分析表明:在1200°C -1500°C下均能合成CaSi₂O₂N₂:Eu²⁺ （δ=0）荧光材料,保温时间长短（1h-12h）对所形成物相结构影响很小,而对荧光发射强度的影响则很明显,这与高温下Eu₂O₃的还原速度和固溶进程有关;随着Eu²⁺掺杂浓度的提高,CaSi₂O₂N₂:Eu²⁺荧光发射光谱发射了红移现象和浓度猝灭效应,这是Eu²⁺之间以偶极子相互作用的方式发生了能量传递造成的;在紫外-可见光（380-450nm）激发下,CaSi₂O₂N₂:Eu²⁺发射出黄绿色光,波长峰值为530-550nm。1400°C保温6h,Eu²⁺离子掺杂浓度为0.02的荧光材料能够与GaN/InGaN蓝光LED （450nm）配合得到2-pcLED;N/O比提高CaSi2ON8/3（δ=1）,荧光材料的激发-发射光谱变宽,这是由于晶格中Eu²⁺周围的晶体场强度增强造成的;经不同浓度HF酸处理,CaSi₂O₂N₂:Eu²⁺的微观形貌发生改变,发射光谱均向长波方向移动;发射强度的改变与HF浓度有关,采用4%HF处理可以提高发射强度达一倍。Ca1-x-2yEuxCeyLiySi2O2N2荧光材料被330nm紫外光激发,发射光谱表现为Ce³⁺和Eu²⁺两个发射峰,发射波长峰值分别位于～400nm和～550nm;x=0.02时,随着Ce³⁺掺杂浓度提高,Eu²⁺发射峰强度增加;y=0.01时,随着Eu²⁺掺杂浓度x的增加,Ce³⁺发射峰强度减弱这是Ce³⁺→Eu²⁺的能量传递造成的;Ca1-xEuxCe0.01Li0.01Si2O2N2荧光粉在紫外光激发下,发射出白光,颜色坐标为（0.167,0.05）^0.349,0.521。在单一晶格中实现白光发射,并且具有热和化学稳定性,是可以用于白光LED的荧光材料。更多还原

【Abstract】 A series of CaSi₂O₂N₂:Eu²⁺ powders have been synthesized through solid-state reaction method under N2-H2 atmosphere. The formation and chemical reaction process was deduced from XRD patterns and PL spectrums of the powders. The crystal structure and fluorescence properties of Ca_1-xEu_xSi₂O_-δN2+2/3δhave been systematically investigated （x=0, 0.005, 0.01, 0.02, 0.04, 0.05, 0.08, 0.1, 0.2;δ=0, 1）. Red-shift and concentration quenching have been deeply discussed. HF treatments have been carried out to improve the microstructure and PL properties of the phosphors.(Eu²⁺, Ce³⁺) co-doped CaSi₂O₂N₂ phosphors have also been prepared, and white light is obtained under UV excitation （330nm） due to Ce³⁺→Eu²⁺ energy transfer mechanism.The experiment results and analysis shows that: single phase CaSi₂O₂N₂:Eu²⁺ （δ=0） powders can be formed during 1200°C to 1500°C, the holding time （1h to 12h） of the above reaction temperatures contribute little to the crystal phase while influence the luminescence properties evidently; High N/O （δ=1） may broaden the excitation spectrum band due to strengthen of the crystal field strength around the Eu²⁺ in the phosphor lattice. As increasing the Eu²⁺ content, the emission spectrum of the phosphor show red-shift and concentration quenching （x=0.02） which due to the interaction between different Eu²⁺ diploes. CaSi₂O₂N₂:Eu²⁺ shows single broad band emission under UV-NUV excitation, centering at 530-550nm. HF treatment process could purify the phase and microstructure, improve the photoluminescence, increase the emission intensity, and the emission spectras change to longer wavelength band.Introducing of Ce³⁺ caused increase of emission intensity of Eu²⁺, while increasing Eu²⁺ concentration the emission intensity of Ce³⁺ decreases due to energy migration over Eu²⁺ ions in the lattice. Resonance-type energy transfers from Ce³⁺ to Eu²⁺ were discovered by directly overlapping the Ce³⁺ emission spectra and the excitation spectra of Eu²⁺.The mechanism of non-radiative energy transfer from Ce³⁺ to Eu²⁺ is found to be electric dipole-dipole interaction. The CIE chromaticity coordinate of (Eu²⁺, Ce³⁺) co-doped CaSi₂O₂N₂ phosphors vary form （0.167, 0.05） to （0.349, 0.521）. Optimization of Eu²⁺ concentration was carried out to produce white light in the prepared Ca0.98-xEuxCe0.01Li0.01Si2O2N2.According to the principle of energy transfer, we demonstrated CaSi₂O₂N₂:Ce³⁺/Eu²⁺ with blue and yellow emission bands exhibited a great potential as a phosphor for NUV-blue light-emitting diodes.更多还原