【作者】 史凌云；

【导师】 姚奎鸿； 王龙成；

【作者基本信息】 浙江理工大学 ， 材料加工工程， 2011， 硕士

【摘要】 稀土荧光粉由于在三基色节能灯、阴极射线管、场发射显示器和等离子体平板显示等技术领域的巨大应用前景而备受关注。然而,目前主要使用的荧光粉是稀土掺杂的以硫氧化物为基质的荧光材料,硫氧化物在使用过程中热稳定性差且容易污染空气,而以氧化物为基质的荧光粉具有良好的热稳定性、使用过程中无有害气体产生、以及发光性能较好的优点。因此,在提高以氧化物为基质的稀土荧光粉发光性能的同时,降低生产成本对其商业化生产具有重大的意义。本论文提出用水热法制备Y₂O₃:Eu³⁺,Gd₂O₃:Eu³⁺和Y₂O₃:Tb³⁺,Gd₂O₃:Tb³⁺,寻找最佳的稀土元素(Eu³⁺和Tb³⁺)掺杂量,并在此基础上引入金属离子(Li⁺,Mg²⁺,Al³⁺)利用共掺杂效应改良,提高荧光粉的发光强度以确定合适掺杂金属离子及最佳掺杂含量,制备出一系列新型荧光粉。得出的主要结论如下:第一、利用水热法制备了红色荧光粉Y₂O₃:Eu³⁺和Gd₂O₃:Eu³⁺,在Y³⁺与Eu³⁺摩尔比为20:1,Gd³⁺与Eu³⁺摩尔比为30:1时荧光粉Y₂O₃:Eu³⁺和Gd₂O₃:Eu³⁺具有最强的发光强度。为了进一步增强荧光粉的发光强度,在此基础上引入金属离子(Li⁺, Mg²⁺, Al³⁺),制备了红色荧光粉Y₂O₃:Eu³⁺:M (M=Li⁺, Mg²⁺, Al³⁺)和Gd₂O₃:Eu³⁺:M (M=Li⁺, Mg²⁺, Al³⁺)。其中Y³⁺:Eu³⁺:Li⁺为20:1:1时发光强度最大,比Y₂O₃:Eu³⁺的发光强度提高了1.06倍;Gd³⁺:Eu³⁺:Li⁺为30:1:0.5时发光强度最大,比Gd₂O₃:Eu³⁺的发光强度提高了2.42倍;Gd³⁺:Eu³⁺:Mg²⁺为30:1:1时发光强度最大,比Gd₂O₃:Eu³⁺的发光强度提高了1.27倍。掺杂Al³⁺后,反而降低了Y₂O₃:Eu³⁺和Gd₂O₃:Eu³⁺的发光强度,说明金属Li⁺比较适合做Y₂O₃:Eu³⁺荧光粉的共掺杂离子,而Li⁺与Mg²⁺离子比较适合做Gd₂O₃:Eu³⁺荧光粉的共掺杂离子。第二、利用水热法制备了绿色荧光粉Y₂O₃:Tb³⁺和Gd₂O₃:Tb³⁺,在Y³⁺与Tb³⁺摩尔比为20:1,Gd³⁺与Tb³⁺摩尔比为30:1时荧光粉Y₂O₃:Tb³⁺和Gd₂O₃:Tb³⁺具有最强的发光强度。为了进一步增强荧光粉的发光强度,在此基础上引入金属离子(Li⁺, Mg²⁺, Al³⁺),制备了绿色荧光粉Y₂O₃:Tb³⁺:M (M=Li⁺, Mg²⁺, Al³⁺)和Gd₂O₃:Tb³⁺:M (M=Li⁺, Mg²⁺, Al³⁺)。其中Y³⁺:Tb³⁺:Li⁺为20:1:1时发光强度最大,比Y₂O₃:Tb³⁺的发光强度提高了1.16倍;Y³⁺:Tb³⁺:Mg²⁺为20:1:10时发光强度最大,比Y₂O₃:Tb³⁺的发光强度提高了1.04倍;Gd³⁺:Tb³⁺:Li⁺为30:1:1时发光强度最大,比Gd₂O₃:Tb³⁺的发光强度提高了1.51倍。Gd³⁺:Tb³⁺:Mg²⁺为30:1:5时发光强度最大,比Gd₂O₃:Tb³⁺的发光强度提高了1.11倍。掺杂Al³⁺后,Y₂O₃:Tb³⁺和Gd₂O₃:Tb³⁺发光强度反而降低了。说明Li⁺与Mg²⁺比较适合做Y₂O₃:Tb³⁺和Gd₂O₃:Tb³⁺的改良离子。第三、利用水热法,制备了红色荧光粉Y₂O₃:Eu³⁺:M (M=Li⁺, Mg²⁺, Al³⁺)及Gd₂O₃:Eu³⁺:M (M=Li⁺, Mg²⁺, Al³⁺)和绿色荧光粉Y₂O₃:Tb³⁺:M (M=Li⁺, Mg²⁺, Al³⁺)及Gd₂O₃:Tb³⁺:M (M=Li⁺, Mg²⁺, Al³⁺)。XRD检测均属于立方结构,不同掺杂离子或同一掺杂离子不同掺杂量对材料的结晶性能和形貌有很大影响。总之,本论文利用水热法,分别以Y₂O₃和Gd₂O₃为基质,稀土掺杂离子(Eu³⁺, Tb³⁺)作激活剂制备了红色和绿色荧光粉,金属离子的引入不同程度的改变了它们的发光强度,实验表明最终确定金属离子Li⁺,Mg²⁺是比较适合的掺杂离子,所掺杂改良的红粉Y₂O₃:Eu³⁺,Gd₂O₃:Eu³⁺和绿粉Y₂O₃:Tb³⁺,Gd₂O₃:Tb³⁺均是发光性能不错的荧光粉。更多还原

【Abstract】 Due to the potential applications in the tricolor energy-saving lamps, cathode ray tube, field emission display and plasma display panel and so on, phosphors based on the rare earth elements （RE） doped materials have attracted enormous interests. However, the mainly used phosphors are the photoluminescence material based on the sulfide. Sulfide based phosphors have many disadvantages such as: poor thermal stability and generation of contamination gas. Even though the RE based phosphors have good photoluminescence properties, the cost is too high. Therefore, it is of great importance to reduce the environment pollution and lower the cost as well as to improve the photoluminescence properties of RE based phosphors.In the thesis, a novel synthesis route of Y₂O₃:Eu³⁺, Gd₂O₃:Eu³⁺ and Y₂O₃:Tb³⁺, Gd₂O₃:Tb³⁺ phosphor was proposed. By adjusting the experimental conditions, the optimum doping amount of activator ions (Eu³⁺ and Tb³⁺) was achieved. Furthermore, metals ions (Li⁺, Mg²⁺, Al³⁺) were co-doped into the phosphors to improve the photoluminescence properties of the as-prepared phosphors, make sure which the best doping ions and theirs the best doping amounts. The major results achieved in the thesis are given as follows:Firstly, red phosphors Y₂O₃:Eu³⁺and Gd₂O₃:Eu³⁺ were prepared by a simple hydrothermal process followed by a post-annealing process. Y₂O₃:Eu³⁺ phosphor achieves the strongest emission intensity as the molar ratio of Y³⁺ to Eu³⁺ is 20:1. Gd₂O₃:Eu³⁺ phosphor achieves the strongest emission intensity as the molar ratio of Gd³⁺ to Eu³⁺ is 30:1. In order to further enhance the emission intensity, metals ions (Li⁺, Mg²⁺, Al³⁺) were doped and red phosphors Y₂O₃:Eu³⁺:M (M=Li⁺, Mg²⁺, Al³⁺) and Gd₂O₃:Eu³⁺:M (M=Li⁺, Mg²⁺, Al³⁺) were prepared. The result showed that red phosphor Y₂O₃:Eu³⁺:Li⁺ achieves the strongest emission intensity as the molar ratio of Y³⁺:Eu³⁺:Li⁺ is 20:1:1, and the emission intensity is 1.06 times as high as that of the Y₂O₃:Eu³⁺ phosphor. Gd₂O₃:Eu³⁺:Li⁺ achieves the strongest emission intensity as the molar ratio of Gd³⁺:Eu³⁺:Li⁺ is 30:1:0.5, and the emission intensity is 2.42 times as high as that of the Gd₂O₃:Eu³⁺ phosphor. Gd₂O₃:Eu³⁺:Mg²⁺ achieves the strongest emission intensity as the molar ratio of Gd³⁺:Eu³⁺:Mg²⁺ is 30:1:1, and the emission intensity is 1.27 times as high as that of the Gd₂O₃:Eu³⁺ phosphor. For the phosphors doped with Al³⁺, the emission intensity of Y₂O₃:Eu³⁺ and Gd₂O₃:Eu³⁺ decreased. The result shows that Li⁺ ions are suitable dopants for the improvement of photoluminescence properties of Y₂O₃:Eu³⁺, while Li⁺ and Mg²⁺ ions are suitable dopants for the improvement of photoluminescence properties of Gd₂O₃:Eu³⁺.Secondly, green phosphors Y₂O₃:Tb³⁺and Gd₂O₃:Tb³⁺ were prepared by a simple hydrothermal process followed by a post-annealing process. Y₂O₃:Tb³⁺ phosphor achieves the strongest emission intensity as the molar ratio of Y³⁺ to Tb³⁺ is 20:1. Gd₂O₃:Tb³⁺ phosphor achieves the strongest emission intensity as the molar ratio of Gd³⁺ to Tb³⁺ is 30:1. In order to further enhance the emission intensity, metals ions (Li⁺, Mg²⁺, Al³⁺) were doped and green phosphors Y₂O₃:Tb³⁺:M (M=Li⁺, Mg²⁺, Al³⁺) and Gd₂O₃:Tb³⁺:M (M=Li⁺, Mg²⁺, Al³⁺) were prepared. The result showed that green phosphor Y₂O₃:Tb³⁺:Li⁺ achieves the strongest emission intensity as the molar ratio of Y³⁺:Tb³⁺:Li⁺ is 20:1:1, and the emission intensity is 1.16 times as high as that of the Y₂O₃:Tb³⁺ phosphor. Y₂O₃:Tb³⁺:Mg²⁺ achieves the strongest emission intensity as the molar ratio of Y³⁺:Tb³⁺:Mg²⁺ is 20:1:10, and emission intensity is 1.04 times as high as that of the Y₂O₃:Tb³⁺ phosphor. Gd₂O₃:Tb³⁺:Li⁺ achieves the strongest emission intensity as the molar ratio of Gd³⁺:Tb³⁺:Li⁺ is 30:1:1, and the emission intensity is 1.51 times as high as that of the Gd₂O₃:Tb³⁺ phosphor. Gd₂O₃:Tb³⁺:Mg²⁺ achieves the strongest emission intensity as molar ratio of Gd³⁺:Tb³⁺:Mg²⁺ is 30:1:5, and the emission intensity is 1.11 times as high as that of the Gd₂O₃:Tb³⁺ phosphor. For the phosphors doped with Al³⁺, the emission intensity of Y₂O₃:Tb³⁺ and Gd₂O₃:Tb³⁺ decreased. The result shows that Li⁺ and Mg²⁺ ions are suitable dopants for the improvement of photoluminescence properties of Y₂O₃:Tb³⁺ and Gd₂O₃:Tb³⁺.Thirdly, red phosphors Y₂O₃:Eu³⁺:M (M=Li⁺, Mg²⁺, Al³⁺) and Gd₂O₃:Eu³⁺:M (M=Li⁺, Mg²⁺, Al³⁺) and green phosphors Y₂O₃:Tb³⁺:M (M=Li⁺, Mg²⁺, Al³⁺) and Gd₂O₃:Tb³⁺:M (M=Li⁺, Mg²⁺, Al³⁺) were prepared by a hydrothermal process. The results of XRD showed that all prepared phosphors with a cubic crystal structure. Different doping ions or same doping ions with different doping amounts have great effect on the structural properties of the as-prepared phosphors.In conclusion, phosphors Y₂O₃:Eu³⁺and Gd₂O₃:Tb³⁺ were prepared by hydrothermal method. It is found that the doping metals ions (Li⁺, Mg²⁺, Al³⁺) may improve the photoluminescence properties and the thermal stability. Finally, the result shows that phosphors: Li⁺ doped red phosphors Y₂O₃:Eu³⁺ and Gd₂O₃:Eu³⁺, Mg²⁺ doped red phosphors Gd₂O₃:Eu³⁺; Li⁺ and Mg²⁺ doped Y₂O₃:Tb³⁺ and Gd₂O₃:Tb³⁺ show better photoluminescence properties.更多还原