含CaF<tsub>2</sub>纳米晶的稀土掺杂透明锗酸盐氧氟微晶玻璃的光谱
文献类型：学位论文
| 作者 | 伍冬 |
| 学位类别 | 硕士 |
| 答辩日期 | 2010 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 张龙 |
| 关键词 | 中红外发光 稀土离子 锗酸盐 氧氟微晶玻璃 |
| 其他题名 | Luminescent Properties of RE Doped Transparent Germanate Oxyfluoride Glass Ceramics Containing CaF2 Nanocrystals |
| 中文摘要 | 氧氟微晶玻璃因结合了氧化物玻璃易于成型、化学性质稳定等优点和氟化物晶体高效发光的性能，近二十年来一直是稀土发光领域的研究热点。目前，国内外对稀土掺杂硅酸盐氧氟微晶玻璃的发光性能已做了比较系统深入的研究。研究内容涉及中红外发光、量子裁剪、白光输出等领域，研究对象包括铒、铥、钬、镱、铽、镨、铈、镝等各类掺杂稀土离子，微晶类型则有氟化铅、碱土金属氟化物等等，而却鲜见有关重金属氧化物氧氟微晶玻璃的报道，基质声子能量低于硅酸盐的锗酸盐氧氟微晶玻璃在中红外发光上有着明显的优势。 本论文首先设计并优化了铒掺杂锗酸盐氧氟微晶玻璃的组成，获得了可控析晶性能优良的先驱体玻璃，对其采用长时间低温热处理工艺制备出透明微晶玻璃样品，XRD图谱显示样品中存在CaF2微晶，结合TEM测试估算微晶尺寸在10-20 nm间，吸收光谱测试则显示微晶玻璃样品的透明性略低于玻璃样品，荧光光谱显示微晶玻璃在波长980 nm辐射光泵浦下出现强烈的上转换发光。 其次，制备了不同浓度Er3+离子掺杂的锗酸盐氧氟微晶玻璃样品。对样品的XRD和NMR测试分析表明Er3+离子已进入微晶并替换了Ca2+离子的格位，氟间隙离子补偿了阳离子电荷差。分析微晶玻璃样品的可见波段上转换荧光强度随Er3+离子掺杂浓度的变化关系得出微晶中Er3+离子的能量转移机制，中红外荧光光谱显示Er3+离子掺杂浓度为5 mol%的微晶玻璃样品的波长2.7 μm发光最强。 然后，分别研究了Tm3+单掺、Tm3+/Ho3+共掺及Yb3+/Tm3+共掺的微晶玻璃样品在2.0 μm波段的发光性能，讨论了微晶化和稀土离子掺杂浓度的变化对样品中红外发光的影响。研究发现微晶玻璃样品发光强度比起玻璃样品都没有明显增强,这可能是因为微晶的声子能量与稀土离子发生能级跃迁所需弥补的能量差不匹配，使得稀土离子发光效率下降。 最后，探索了锗酸盐氧氟微晶玻璃样品的白光输出性能，发现改变样品中Er3+离子和Yb3+离子的掺杂浓度或对玻璃样品微晶化都可改变样品上转换发光的颜色。基于以上两点可进一步研究调控样品发光的颜色，以获得高质量的白光输出。 |
| 英文摘要 | Combining the merits of easy forming and good chemical stability in the oxide glasses and the excellent luminescent performances of the fluoride crystals, oxyfluoride glass ceramics (OGC) have attracted the researchers in the field of rare earth (RE) luminescence since the early 1990s. So far, the luminescent properties of RE doped silicate OGC have been systematically studied around the world aiming at mid-infrared emission, quantum cutting and white light emission. The RE ions such as Er3+, Tm3+, Ho3+, Yb3+, Tb3+, Pr3+, Ce3+, Dy3+ etc have been studied and the PbF2 and alkali metal fluoride nanocrystals have been obtained in the glass ceramics. However, few researches have been carried out on heavy metal oxide OGC like germanate OGC, which possess superiority over silicate on mid-infrared emission for their much lower maximum phonon energy. In this paper, a composition of germanate OGC was designed and adjusted, and the precursor glass in the optimal composition was obtained with the crystallization fine controlled. Transparent glass ceramics were prepared after the heat treatment upon the precursor glass at lower temperature for a long time. The XRD pattern indicated the existence of CaF2 nanocrystals in the glass ceramic samples with the size 10-20 nm. The absorbance spectra showed glass ceramics in worse transparency than the precursor glass. However, much stronger upconversion luminescence emerged in the glass ceramics excited by 980 nm LD. Secondly, the glass ceramic samples in different Er3+ contents were prepared. The XRD and NMR analysis indicated the Er3+ ions have entered into the nanocrystals by replacing the lattice site of the Ca2+ ions and the charge difference is compensated by the fluoride interstitial ions. The mechanism of energy transfer between Er3+ ions in CaF2 nanocrystals was concluded from the relationship between the upconversion luminescence intensity and the Er3+ content in the glass ceramics. The mid-infrared luminescent spectra showed the optimal content of Er3+ in the glass ceramic samples was 5 mol%, i.e. the strongest luminescence intensity was obtained. Then, the mid-infrared luminescent properties of germanate glass ceramics doped with Tm3+ and codoped with Yb3+/Tm3+ or Tm3+/Ho3+ were investigated respectively. The influences of the nanocrystallization process and the Er3+ content on the mid-infrared luminescence intensity were also discussed. The luminescence intensity in the glass ceramics was weaker than that in glass, which may due to the mismatch between the phonon energy in nanocrystals and the energy that facilitates the transitions among the energy levels, thereby lowers the luminescence efficiency. Lastly, the white light emission performances of germanate OGC samples were studied. The color of the upconversion emissions in samples can be altered by changing the contents of Er3+ ions and Yb3+ ions or by adopting heat treatment at different temperatures. In these two methods, white light of high quality could be obtained in further study. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16679]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 伍冬. 含CaF<tsub>2</sub>纳米晶的稀土掺杂透明锗酸盐氧氟微晶玻璃的光谱[D]. 中国科学院上海光学精密机械研究所. 2010. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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