【作者】 李巍；

【导师】 陈文哲；

【作者基本信息】 福州大学 ， 材料学， 2014， 博士

【摘要】 稀土与过渡族离子掺杂尖晶石微晶玻璃综合光学晶体与光学玻璃的特点,可具有与晶体相近甚至更好的光谱性能,在LED照明、被动调Q激光器、近红外光纤放大器、太阳能电池等领域具有重要应用前景。为了深入探索微晶分布、掺杂离子的种类与分布等对尖晶石微晶玻璃发光性能的影响,本文针对目前尖晶石光学晶体制备工艺复杂、物化稳定性不好及氧化物光学玻璃光学性能差等问题,采用溶胶一凝胶法,通过制备工艺的优化,结合掺杂技术制备以尖晶石系纳米晶相(ZnGa2O4、γ-Ga2O3和ZnAl2O4)为主组成的新型光功能纳米复合材料——尖晶石系氧化物微晶玻璃,并以稀土离子(Eu3+, Tb3+)或过渡族金属离子(Co2+)作为掺杂的发光中心,制备了一系列激活离子掺杂的透明纳米晶尖晶石系氧化物微晶玻璃材料。利用差热分析(DTA-TG).傅里叶红外分析(FT-IR)、X射线粉末衍射(XRD)、荧光光谱、透射电子显微镜(TEM)等测试手段,系统深入地研究了合成制备工艺及参数、热处理温度、组分、掺杂激活离子等对材料的显微结构与发光性能的影响规律。通过组分调整与溶胶-凝胶工艺参数改进,实现对所研究微晶玻璃体系纳米复合结构的调控,成功制备了透明的ZnAl2O4三种系列的纳米晶尖晶石系氧化物微晶玻璃,并揭示了微晶玻璃中纳米晶相结构的主要控制因素。XRD测试结果表明干凝胶样品在800～900℃热处理后可得到透明的含尖晶石结构ZnGa2O4微晶玻璃；在1000℃热处理时由于非晶基体晶化析出三方Zn2SiO4与六方Si02晶相导致样品失透。获得了高晶相组分(高达12 mol%ZnAl2O4和高达20mol%γ-Ga2O3)制备了Tb3‘离子、Eu3+离子掺杂,以及Tb3+/Eu3+共掺ZnGa2O4-SiO2微晶玻璃,系统研究了热处理温度对材料显微结构的影响以及不同稀土离子掺杂材料的发光性能。激发光谱证实在微晶玻璃中具有ZnGa2O4纳米晶到Tb3+离子与Eu3+离子的能量传递。发射光谱分析表明在900℃热处理Tb3+/Eu3+:ZnGa204.SiO2微晶玻璃样品中,Tb3+离子与Eu3+离子分别发射绿光和红光,并与ZnGa204纳米晶发射的蓝光组合成了与标准等能白光发射坐标十分接近的白光发射。该材料在白光LED领域具有潜在的应用前景。成功制备了Eu3+离子掺杂含γ-Ga203纳米晶透明微晶玻璃,获得了系列稀土Eu3+离子掺杂的不同摩尔百分比的纳米复合微晶玻璃(1Eu3+’:Xγ-Ga2O3-10ZnO-(89-X)SiO2 (X=0,5,10,15,20)).XRD和TEM测试表明,在600℃以上热处理可以在非晶态的基体中均匀分布着立方结构的γ-Ga203纳米晶。通过激发谱证实,当γ-Ga203纳米晶吸收紫外光后,通过向稀土Eu3+离子传递能量提高Eu3+离子的红光发光强度,使Eu3+离子的发射强度随着γ-Ga203含量的增加而显著提高,特别地,含20 mo1%的γ-Ga203试样,其Eu3+离子的发射强度是未掺杂试样的5.5倍。为了比较研究Eu3+离子在具有尖晶石γ-Ga203-SiO2晶体结构中的发光性能,制备了Eu3+离子掺杂的具有金红石结构的Sn02-SiO2微晶玻璃。在280 nm激发下,发射光谱分析表明在800℃热处理Eu3+:SnO2-SiO2微晶玻璃样品中,出现了Stack分裂,表明Eu3+离子进入了Sn02纳米晶相中。成功制备了透明Co2+:ZnAl2O4-SiO2块体微晶玻璃。ZnAl2O4纳米晶平均晶粒尺寸为12～14 nm。在红外光吸收谱1200～1600 nm处有很强的吸收宽峰,是四配位Co2+离子的4A2→4T1(4F)跃迁,且随着热处理温度的提高,吸收强度增强,吸收截面系数为1.15×10-19 cm2。所得微晶玻璃在铒玻璃激光器的被动Q开关中具有潜在的应用。通过晶化控制,获得含Tb3+/Eu3+共掺的ZnAl2O4-SiO2透明微晶玻璃,该玻璃显示了优异的发光性能。通过调整Tb3+和Eu3+浓度比,其发光颜色从绿光和红光可以全程调控,有望发展为优良光功能材料。更多还原

【Abstract】 Rare earth ions or transition metal ions doped glass ceramics containing spinel-type nanocrystals combine the advantage of the optical crystal and the optical glass. Because of their optical properties are close to the crystals, until now, there have been important applications for them in the white LED, passive tunable Q laser and near infrared optical fiber amplifier, solar cells and so on. However, due to the current existing disadvantages of optical characteristics from the oxide glass and lacking mechanical and chemical properties from the nanocrystals, and hope to explore the influence of the compositions and preparation technique on the micro-structure and the luminescence poperties of the glass ceramics, the transparent glass ceramics containing spinel-type nanocrystals with doped ions of rare earth ions or transition metal ions have been synthesized by sol-gel method, and the micro-structure and photolumimescence properties have been investigated in this thesis. Especially, the active ions such as the rare-earth ions (Eu3+, Tb3+) and transparent ions (Co2+) were doped in the glass ceramics containing spinel-type nanocrystals (ZnGa2O4, γ-Ga2O3 & ZnAl2O4). And the Differential thermal analysis and Thermal gravity analysis (DTA-TG), Fourier translation infrared spectroscopy (FT-IR), X-ray diffraction (XRD), luminesce spectroscopy, and Transmission electron microscope (TEM) were used to research the influence of the composition, heat treatment temperature, and doping activating ions to the micro-structure and the properties of the materials. The main results are as follows.The transparent glass ceramics containing spinel-type nanocrystal, such as ZnGa2O4, γ-Ga2O3 and ZnAl2O4 with doped ions of rare earth ions or transition metal ions were successfully gained by improving the process parameters of sol-gel method. Especially, it synthesized successfully the high crystal (more than 12 mol% ZnAl2O4 and more than 20 mol% γ-Ga2O3), too. And then, the performance optimization throught the controlling of microstructure is achieved. It reveals the main control factors of the nano-crystalline phase structure in the glass ceramics, the evolution law of the glass ceramics structure with the heat treatment.The results of the XRD show that the spinel-type ZnGa2O4 nanocrystal appears in glass matrix as the dry-gels heat-treated in the range of temperature from 800℃ to 900℃. But the samples are devitrified with the extra trigonal Zn2SiO4 and hexagonal SiO2 crystals when the heat-treating temperature up to 1000℃.The ZnGa2O4-SiO2 glass ceramics doped Tb3+, Eu3+ and co-doped with Tb3+/Eu3+ were synthesized by the sol-gel method, respectively. The influence of the composition and the thermal temperature on the microstructure and the photoluminescence properties of the glass ceramics doped with different rare-earth ions were studied. The excitation spectra demonstrate the energy transfer from ZnGa2C>4 nanocrystal to the Tb3+and Eu3+ ions in the glass ceramics. The emission spectra indicates that there is the green light for Tb3+ ions or the red light for Eu3+ions observed in the emissions spectra respectively, in the Tb3+ions and Eu3+ions co-doped Tb3+/Eu3+ZnGa2O4-SiO2 glass ceramics heat-treated at 900℃. It is very interesting that while light can be realized by combination of these two emissions with the blue light emission from the ZnGa2O4 nanocrystal, when the Tb3+/Eu3+ ZnGa2O4-SiO2 glass ceramics are excited by the ultraviolet light.The transparent glass ceramics containing different concentration of γ-Ga2O3 nanocrystals (1Eu3+:Xγ-Ga203-10ZnO-(89-X)Si02 (X=0,5,10, 15,20))were successfully synthesized, respectively. XRD and TEM observation reveal that γ-Ga2O3 nanocrystals are formed and distributed homogeneously among the amorphous matrix. Importantly, the Eu+ emission intensity of the nano-composite with 20% mol%γ-Ga2O3 is about 5.5 times stronger than that of the sample without γ-Ga2O3, which is attributed to the effective energy transfer from the γ-Ga2O3 nanocrystal to the rare earth Eu3+ions.The Eu+:Sn02-SiO2 glass ceramics with rutile-type nanocrystals were synthesized to compare the photoluminescence of the spinel-type glass ceramics. The emission spectra excited at 280 nm showed that there was stack split in the Eu3+:SnO2 glass ceramics heat-treated up to 800℃, which means some Eu3+ have inserted the SnO2 nanocrystals.The transparent Co2+:ZnAl2O4-SiO2 block glass ceramics with doped of transition metal ions Co2+ were synthesized by sol-gel method, too. The average size of the ZnAl2O4 nanocrystals were 12-14 nm. The result shows that the glass ceramics exhibit a broad absorption band in the range of 1200-1600 nm. And the absorption coefficient enhances with the increasing of heat-treating temperature, which is characteristic of 4A2→4T1(4F) transition from the tetrahedral Co2+ ions. It is found that the absorption cross section reaches 1.15×10-19 cm2 when the heat-treating temperature is up to 1000℃, which means it can be applied in the passive Q-switch turnable laser.ZnAl2O4-SiO2 transparent glass ceramics co-doped with Tb3+ and Eu3+ were successfully synthesized by the sol-gel method. The glass ceramics exhibit the excellent luminescence, which changes from green to the red emission with adjusting the concentration of the Tb3+/Eu3+. It suggests the potential application as optical functional materials.更多还原