稀土离子激活的磷酸钪锶及卤铝酸锶发光性质的研究
文献类型：学位论文
| 作者 | 董晓玲 |
| 学位类别 | 博士 |
| 答辩日期 | 2014-07 |
| 授予单位 | 中国科学院大学 |
| 导师 | 张家骅 |
| 学位专业 | 凝聚态物理 |
| 中文摘要 | 与传统的荧光灯和白炽灯相比白光LED光源具有体积小，全固态，发光效率高，寿命长和绿色环保等特点，近年来已逐渐成为固态照明领域的研究热点。目前获得白光LED的主要途径是在蓝光或近紫外InGaN芯片上涂覆荧光粉。其中，近紫外基白光LED与蓝光管芯白光LED相比具有可实现较高的显色性和色彩稳定性等优点。因此研制适用于近紫外光激发的高效荧光粉是获得高质量白光的首要问题。 磷酸盐体系发光材料具有合成工艺简单，成本低，发光效率高以及化学性质稳定等优点，近年来也引起了广泛的关注。本论文以获得适用于近紫外激发的高效荧光粉为目标，研究了Eu2+/Ce3+，Mn2+ 共掺杂的Sr9Sc(PO4)7及Sr9Sc(PO4)7:Eu3+荧光粉的晶体结构和发光性质。 电子俘获型光转换材料又被称为光激励发光材料。自美国的Lindmayer于1986年提出以来便引起了广泛的关注。光激励发光材料在光存储、X射线成像红外探测以及红外光转换等方面有着较好的应用前景。目前，已经商业化的红外转可见材料主要是碱土金属硫化物，但是，硫化物的化学性质很不稳定并且分解后的产物有毒，会对环境造成严重的污染。因此迫切寻找一种化学性质稳定的红外转可见光激励发光材料。本论文以Sr3Al2O5Cl2: Eu2+为研究对象，通过掺杂共激活剂的方式引入陷阱以此来提高光激励发光性能。 取得的主要研究成果如下： 1、通过高温固相法制备了Sr9Sc(PO4)7:Eu2+,Mn2+荧光粉。对样品的合成、结构精修和发光性质进行了详细地研究。样品在250-450nm间存在一个很强的激发带，与近紫外LED芯片的发射波长符合较好。在365nm激发下，在Sr9Sc(PO4)7:Eu2+,Mn2+体系中观察到了发射峰值位于510nm和610nm的黄光发射，实现了Eu2+向Mn2+的高效敏化发光。通过改变Mn2+的浓度，可以使Sr9Sc(PO4)7:Eu2+,Mn2+荧光粉的半高宽达到170nm左右。最后利用测得的荧光寿命数据，系统地研究了Eu2+-Mn2+的能量传递机理。 2、通过高温固相法制备了Sr9Sc(PO4)7:Ce3+,Mn2+系列样品并对其发光性质进行了研究。样品的激发光谱在240-350nm范围内。在310nm激发下，观察到了位于370nm的来自Ce3+的5d–4f的跃迁和610nm来自Mn2+的d–d跃迁。随着Mn2+浓度的增加，Ce3+-Mn2+间能量传递效率逐渐提高，Mn2+位于610nm处的红光发射逐渐增强。通过测得的荧光寿命数据，研究了Ce3+-Mn2+的能量传递机理。最终通过改变Mn2+的浓度，可以获得适于紫外激发的橙红色荧光粉。 3、通过高温固相法制备了Sr9Sc(PO4)7:xEu3+系列样品。对近紫外光激发下样品的发光性质进行了研究，发现该系列样品可以被394nm近紫外光有效地激发，发射出橙红色光。随着Eu3+浓度的增加，其发光强度逐渐增强，当x=0.4时，发光强度达到最大值。猝灭温度在200℃以上。 4、通过高温固相法制备了Sr3Al2O5Cl2: Eu2+, Ln3+(Ln=Nd、Sm、Dy、Tm、Yb)系列样品，研究了不同的共激活剂对Sr3Al2O5Cl2:0.01Eu2+光激励发光性质的影响。经研究发现，掺杂Tm3+的样品其光激励发光性能有很大的提高。所以我们以Sr3Al2O5Cl2:0.01Eu2+,Tm3+为主要研究对象，讨论了Tm3+浓度对光激励发光性能的影响。实验结果表明，在体系中掺入Tm3+后，其光激励发光亮度和光存储量都有明显的提高。当x=0.007时，其光激励发光强度是单掺Eu2+时的441和91倍，其光存储量是SrS: Eu2+, Sm3+的3倍。 |
| 英文摘要 | In recent years, white light emitting diodes (LEDs) are considered to be the hot area of research in the field of solid-state lighting due to their higher luminous efficiency, longer lifetime and environment friendly compared with the conventional light sources such as incandescent lamps or fluorescent lamps. Until now, the most widely used commercial white LEDs are fabricated by combining high performance blue or near UV InGaN chip with phosphors. Compared to the blue chip based white LEDs, the white LEDs obtained by combining near UV LED chips with tricolor phosphors have the advantages, for instance, high color rendering index and color stability. Therefore, the primal problem to obtain high quality LEDs is looking for some high-efficient phosphors that can be excited by near-UV light. Phosphate phosphors have attracted more attention as host materials for the application in near UV LEDs due to their low synthesis conditions, low cost, high luminous efficiency and high chemical stability. The main purpose of this study is to obtained high-efficient phosphors that can be used in near-UV LEDs. Thus, studies on the crystal structure and photoluminescence properties of Eu2+/Ce3+, Mn2+ codoped Sr9Sc(PO4)7 and Sr9Sc(PO4)7:Eu3+ have been carried out. Electron trapping materials is also called the photostimulated luminescence materials. This kind of material has been always focused on extensively Since 1986, the photostimulated luminescence materials were first referred by Lindmayer, it has been attracted increasing interest. This materials can be used on optical storage, X-ray imaging, infrared detection and photostimulated luminescence materials. At present, the commercial photostimulated luminescence materials which is used in the photostimulated luminescence materials aspect is alkaline sulfides. However, the chemical stability of alkaline sulfides is poor and the product of decomposition will pollute the environment. Therefore, it is urgent to search new photostimulated luminescence materials which have good chemical stability. In this paper, we improve the photostimulated luminescence properties of Sr3Al2O5Cl2: Eu2+ through codoped rare earth ions. The main studies and results are listed as follow: 1、Eu2+–Mn2+ codoped yellow-emitting Sr9Sc(PO4)7 phosphors have been synthesized by solid-state reactions. The synthesis, structure refinement, and luminescence properties of the obtained phosphor were investigated in detail. The obtained phosphor exhibits a strong excitation band between 250 and 450 nm, matching well with the dominant emission band of a near-UV light-emitting-diode (LED) chip. Upon excitation at 365 nm, the Sr9Sc(PO4)7:Eu2+,Mn2+ phosphor shows strong yellow emissions centered at 510 and 610 nm. With increasing the concentration of Mn2+, the FWHM can reach 170nm.The energy transfer mechanism from Eu2+ to Mn2+ in Sr9Sc(PO4)7:Eu2+, Mn2+ has been studied based on the decay lifetime data. 2、A series of Ce3+ and Mn2+ co-doped Sr9Sc(PO4)7 phosphors have been synthesized by high temperature solid state reaction and their luminescence properties are investigated. The obtained phosphors exhibit a broad excitation band ranging from 240 to 350 nm and two emission bands centered at about 370 and 610 nm upon 310 nm excitation, resulting from the 5d–4f transitions of Ce3+ and the d–d forbidden transition of Mn2+, respectively. Energy transfer mechanism from Ce3+ to Mn2+ in Sr9Sc(PO4)7 host matrix was studied based on the decay lifetime data. Through effective energy transfer, a color-tunable emission varied from blue to reddish orange can be realized by adjusting the ratio of Ce3+ to Mn2+. 3、A series of Eu3+ ions doped Sr9Sc(PO4)7 orange–red emitting phosphors have been prepared by solid-state reaction method. Photoluminescence properties under near-ultraviolet (NUV) light excitation of the samples have been carried out. The studies show that the samples can be effectively excited by NUV (394 nm) which matches to the output wavelengths of near UV chips and exhibits intense orange–red emissions. Eu3+ concentration was found to be optimum at x = 0.4 and the thermal quenching temperature of Sr9Sc(PO4)7:0.4Eu3+ is above 200℃. 4、Sr3Al2O5Cl2: Eu2+, Ln3+(Ln=Nd、Sm、Dy、Tm、Yb) phosphors have been synthesized by solid-state reactions. The effect of different rare earth ions on photostimulated luminescence properties has been studied. And strong and long-lasting photostimulated luminescence is observed and studied in Eu2+ and Tm3+ codoped Sr3Al2O5Cl2 under 980 nm continuous stimulation after UV and blue light pre-irradiation. Compared to the Eu2+ singly doped one, the PSL intensity and energy storage capacity in the doubly doped material are enhanced by a factor of 441 and 91, respectively. The study indicates that codoping Tm3+ leads to a large increase of traps that enlarge energy storage capacity as three times as the commercial phosphor SrS:Eu2+, Sm3+. |
| 语种 | 中文 |
| 公开日期 | 2014-08-21 |
| 源URL | [http://ir.ciomp.ac.cn/handle/181722/41400]  |
| 专题 | 长春光学精密机械与物理研究所_中科院长春光机所知识产出 |
| 推荐引用方式 GB/T 7714 | 董晓玲. 稀土离子激活的磷酸钪锶及卤铝酸锶发光性质的研究[D]. 中国科学院大学. 2014. |
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