【作者】 梁晓峦；

【导师】 陈国荣；

【作者基本信息】 华东理工大学 ， 材料科学与工程， 2011， 博士

【摘要】 目前,“绿色照明”已成为人类社会现代化程度的重要标志之一,是关系到人类社会可持续发展的一项重要措施。和传统的白炽灯和荧光灯相比,白光LED (white light emitting diode, W-LED)具有节能、环保、长寿命等优点,被认为是新一代的照明光源,受到人们广泛的关注。因此,白光LED是“绿色照明”的重要组成部分之一。在白光LED的应用背景下,本课题研究了稀土离子／过渡金属离子掺杂的发光玻璃／玻璃陶瓷材料。发光玻璃／玻璃陶瓷相比较粉体发光材料而言,具有独特的优势,如制造成本低、减少光圈效应和发光稳定和可调等。尤其是荧光玻璃可与LED芯片直接蚀刻“扣装”成白光器件,因此对简化树脂封装工艺、提高热稳定性和出光效率以及发展面光源有重要意义。实验采用熔体冷却法分别制备了稀土离子Tb3+、Sm3+、Eu2+、Eu3+、Dy3+、Tm3+和Er3+单掺或者共掺的硅酸盐玻璃,硼酸盐玻璃／玻璃陶瓷和磷酸盐玻璃。此外还制备了稀土离子Tb3+、Eu2+和过渡金属离子Mn2+单掺和共掺的磷酸盐玻璃。利用吸收光谱、透过光谱、激发光谱,发射光谱和色品坐标的计算研究了发光玻璃／玻璃陶瓷的光学性能。借助差热分析和X-射线衍射分别研究了玻璃的热力学性能和玻璃陶瓷中的晶相。通过静水力学法和傅里叶红外透过光谱分别得到了样品的密度和玻璃的网络结构参数。通过电子顺磁共振分析了过渡金属离子Mn2+的浓度变化对配位场的影响。特别的是,基于以上的测试结果,我们分析了稀土离子的浓度猝灭机理和稀土离子间、稀土离子和过渡金属离子间能量传递的机理。此外,本文还研究了白光LED用发光材料的抗辐照性能。实验结果表明：Tb3+离子和Sm3+离子在玻璃中受紫外光激发后产生绿光和红橙光发射,并且存在Sm3+离子发光浓度猝灭和Tb3+→Sm3+能量传递的现象。伽玛射线辐照使得Tb3+/Sm3+共掺玻璃在可见光区域产生强烈的吸收,并且明显地降低了发光强度。除此之外,伽马射线辐照还能还原玻璃中的Tb4+离子到Tb3+离子。对Tb3+/Sm3+共掺硼酸盐玻璃进行热处理获得了玻璃陶瓷。玻璃陶瓷中析出了SrAl2B2O7晶相并且Tb3+离子和Sm3+离子进入晶相,增强了发光。Tb3+离子、Eu2+离子和Eu3+离子可以同时存在于大气气氛下熔制的Tb/Eu共掺铝硅酸盐玻璃中,产生蓝光、绿光和红光发射,并且由此复合出白光。相同制备条件下,Eu2+离子无法稳定存在于Tb/Eu共掺锌硅酸盐玻璃中,但是Tb3+→Eu3+能量传递更加明显,相应的传递机理是四极-四极反应。Dy3+离子掺杂的磷酸盐玻璃受紫外激发后产生蓝光和黄光发射,并且发光强度随着玻璃组成的变化而变化。Tm3+离子的加入起到了补充蓝光的作用,进而调节复合光色品坐标进入白光区域。Er3+离子掺杂的磷酸盐玻璃受蓝光激发后产生多色发光,但是Er3+离子在很低浓度情况下就会产生浓度猝灭效应。Er3+离子发光在玻璃和玻璃陶瓷材料中的表现截然不同。Tm3+离子会传递能量给Er3+离子,增强Er3+离子的红光发射。Tb3+离子和Mn2+离子在磷酸盐玻璃中分别产生绿光发射和宽带红光发射。Mn2+离子的发射峰波长随着掺杂浓度的增加出现红移现象。光谱表明,Tb3+离子通过偶极-四极反应将部分能量传递给Mn2+离子。Eu2+离子和Mn2+离子掺杂的磷酸盐玻璃会产生从紫光到红光的连续发射光谱,并且Eu2+离子可以将能量以很高的效率传递给Mn2+离子,相应的机理是偶极-偶极反应。色品坐标表明,Eu2+/Mn2+共掺玻璃的发光可以进入白光区域,符合白光LED色品坐标方面的要求。通过样品制备和性能表征可知,稀土离子和过渡金属离子在玻璃和玻璃陶瓷中表现出了良好的发光性能,并且部分样品的色品坐标已经进入白光区域,复合白光LED的要求。因此,发光玻璃／玻璃陶瓷是一种具有潜力发光材料,具有应用在白光LED中的前景和深入研究的价值。更多还原

【Abstract】 Recently, "Green Illumination" becomes an important symbol of the modernization degree for human society, which is also related to sustainable development of nature source. Compared with incandescence and fluorescenc, white light emitting diode (W-LED) has lots of merits, such as energy saving, environment friendly, long lifetime etc. Therefore, as a novel light source, W-LED is one of essential parts of "Green Illumination" attracting much attention. Under the background of W-LED application, we we have a series of research on rare earth ions (REn+)/transition metal ions (TMn+) doped luminescence glass/glass ceramics materials. Compared with the traditional phosphors, luminescence glass/glass ceramics have some distinctive advantages, such as lower manufacturing cost, free of halo effect, adjustable luminescence property etc. In particular, glasses can be molded directly with LED chips, so that free-resin assembly can be realized which will further improve the thermal stability of W-LED set.In the present thesis, the Tb3+, Sm3+, Eu2+, Eu3+, Dy3+, Tm3+ and Er3+ ions dope/co-doped silicate glass, borate glass/glass ceramics and phosphate glass as well as Tb3+, Eu2+ and Mn2+ doped/co-doped phosphate glass are prepared successfully by melting-quenching method. The optical properties are analyzed by absorption spectrum, transmittance spectrum, excitation spectrum, emission spectrum and calculated chromaticity coordinates. The thermodynamic property of glass and the crystalline phase in glass ceramics are studied with the help of by Differential Thermal Analysis and X-ray diffraction measurement. The glass density and the glass network structure information are gained by hydrostatic test method and FT-IR transmittance spectrum. The effect of the increasing Mn2+ concentration on their ligand filed surrounding is investigated by Electron Paramagnanetic Resonance method. Furthermore, We especially discuss the concentration quenching mechanism of REn+ and the energy transfer mechanism between REn+ ions or REn+ and TMn+ ions in glasses. Furthermore, study on irradiation resistance of these luminescence glasses is also included.The relevant research results are listed as follows. Tb3+ and Sm3+ doped in glass can give green and orange-reddish emissions under the UV light excitation, respectively. In co-doped glass sample, the concentration quenching phenomenon of Sm3+ ions and an energy transfer from Tb3+ to Sm3+ ions are also obvious in the emission spectra. Gamma-ray irradiation can cause a new absorption in visible spectrum range for Tb3+/Sm3+ co-doped glass and can reduce the emission intensity significantly. Gamma-ray irradiation can also reduce Tb4+ ions to Tb3+ ions in glass. The glass ceramics could be obtained by the heat treatment of the parent glasses. The SrAl2B2O7 crystal phase containing Tb3+ and Sm3+ ions was precipitated, which plays a positive effect on emission intensity. The blue, green and red emissions from Tb3+, Eu2+ and Eu3+ ions can be observed simultaneously in aluminosilicate glass melted in atmosphere, which results in the final white light emitting. Even under the same melting condition, Eu2+ ion in not stable in zinc silicate glass. However, the energy transfer from Tb3+ to Eu3+ is clearer and the relevant mechanism is quadrupole-quadrupole interaction.The phosphate glass doped with Dy3+ ions emits blue and yellow lights excited by UV light and the emission intensity changes with different glass compositions. When Tm3+ ion is introduced into Dy3+ doped glass, the blue emission is enhanced, which adjusts the combined light into White Light Region. After blue light excitation, Er3+ ions could give several emissions in visible spectrum but the concentration quenching effect is easy to come out even at lower dopant concentration. The luminescence behavior of Er3+ ion in glass is much different from that in glass ceramics. Tm3+ ions could transfer energy to Er3+ ions to strengthen Er3+ red emission in co-doped glass. The phosphate glass doped with Tb3+ and Mn2+ ions can generate green emission and broad red emission band. There is a red shift of Mn2+ emission wavelength with increasing dopant concentration. An energy transfer from Tb3+ to Mn2+ ions takes place under the way of dipole-quatrupole interaction. Eu2+ and Mn2+ ions in phosphate glass can result in a continual emission from violet to red light regions under the 350 nm excitation. Meanwhile, Eu2+ ions can transfer energy to Mn2+ ions with high efficiency and the transfer mechanism is dipole-dipole interaction. The calculated chromaticity coordinates of Eu2+/Mn2+ co-doped glass can move into the white light region, which matches the demand of W-LED application.From the sample preparation and property characterization processes, we can find that the REn+ and TMn+ions express excellent luminescence properties in glass and glass ceramics. The chromaticity coordinates of some samples have moved into white light region, which matches the demand of W-LED application. Therefore, it can be concluded that as a kind of potential luminescence material, luminescence glass/glass ceramics have W-LED application prospect and the great value for further study.更多还原