纳米核壳氟化物材料的合成及其荧光性质、光温特性研究
发布时间：2018-08-15 17:49
【摘要】：进入21世纪以来,随着纳米技术的飞速发展,稀土掺杂的纳米材料因其在光、电、磁等方面显现出的优异的性质而受到了科研工作者的广泛关注。其中,稀土掺杂纳米材料在增强太阳能效率和荧光测温领域的应用成为研究热点。一方面,由于太阳能电池材料本身的能带间隙小(1.12eV),而太阳光谱是一个宽光谱,导致太阳光中的很大一部分红外光和紫外光无法被电池吸收利用。因此,寻找优异的光谱转换材料成为提升太阳能利用效率的关键因素。稀土离子掺杂的氟化物材料由于具有卓越的光转换效率,被广泛应用于上转换和下转换发光材料。我们利用高温裂解方法制备了高性能的NaGdF4:12%Er3+及具有核壳结构的纳米材料,通过测试TEM、XRD等手段对其具体结构和形貌进行了表征。测试结果表明,合成的NaGdF4:12%Er及NaGdF4:12%Er@Na GdF4:x%Er核壳纳米材料都具有良好的单分散性,在结构上,分别表现出均一的四方相和六角相结构。通过调节纳米颗粒的壳层中的铒离子掺杂浓度,当壳层中的掺杂浓度达到10mol%时,对比于单层纳米颗粒,稀土离子掺杂的核壳纳米颗粒实现了高达336倍的荧光增强。同时,结合铒离子的能级结构,分析了不同掺杂浓度下核壳纳米颗粒的荧光寿命以及红绿光比、半高宽的差异,最终得出了核壳纳米颗粒中铒离子的主要上转换发光机制。另一方面,由于受外界干扰小、抗激发功率噪声强等优点,稀土掺杂纳米材料在荧光测温领域的研究也逐渐发展成为热门课题。本论文中,利用水热法调节不同试剂,最终合成了纳米球、微米棒、六角盘、纺锤状、微米球和类八面体六种不同形貌的NaYF4:Er颗粒。通过具体TEM测试,实验确定了合成的颗粒的具体形貌。在统一的掺杂浓度下,针对不同形貌,研究了其能量传递机制,详细分析了颗粒的形貌下对光温传感方面的影响。同时,本文研究了将Yb作为敏化剂,不同的稀土离子(RE,RE=Ho,Tm,Pr,Tb)作为激活离子的情况下,共掺杂稀土离子纳米颗粒的光温传感特性。通过具体TEM测试可以看出,实验得出的纳米颗粒都具有良好的单分散性。对比最佳配比下的不同共掺杂纳米颗粒可以看出,Pr和Yb离子共掺杂比其他共掺杂情况具有更加优异的光敏特性,在光敏应用方面具有更大潜力。
[Abstract]:Since the 21st century, with the rapid development of nanotechnology, rare-earth doped nanomaterials have attracted wide attention because of their excellent properties in light, electricity, magnetism and so on. Among them, the application of rare earth doped nanomaterials in enhancing solar energy efficiency and fluorescence temperature measurement has become a research hotspot. On the one hand, due to the small energy band gap (1.12eV) of the solar cell material itself, and the solar spectrum is a wide spectrum, a large part of the infrared and ultraviolet light in the solar light can not be absorbed and utilized by the cell. Therefore, the search for excellent spectral conversion materials has become a key factor to improve solar energy efficiency. Rare earth ion doped fluorides have been widely used in upconversion and downconversion luminescence due to their excellent optical conversion efficiency. High performance NaGdF4:12%Er3 and nanomaterials with core-shell structure were prepared by high temperature pyrolysis method. The results show that the synthesized NaGdF4:12%Er and NaGdF4:12%Er@Na GdF4:x%Er core-shell nanomaterials have good monodispersity and have homogeneous tetragonal and hexagonal structure respectively. By adjusting the erbium ion doping concentration in the shell layer of the nanoparticles, when the doping concentration in the shell layer reaches 10 mol%, compared with the monolayer nanoparticles, the fluorescence intensities of the core and shell nanoparticles doped with rare earth ions are 336 times higher than those of the monolayer nanoparticles. At the same time, according to the energy level structure of erbium ion, the fluorescence lifetime, the ratio of red and green light, and the width of half-maximum of the core-shell nanoparticles with different doping concentration were analyzed. Finally, the main up-conversion luminescence mechanism of erbium ion in the core-shell nanoparticles was obtained. On the other hand, due to the advantages of low external interference and strong anti-excitation power noise, the research of rare-earth doped nanomaterials in the field of fluorescence temperature measurement has gradually become a hot topic. In this paper, the hydrothermal method was used to adjust different reagents. Finally, six kinds of NaYF4:Er particles with different morphologies were synthesized, such as nanospheres, micron rods, hexagonal disks, spindles, microspheres and octahedron-like particles. The morphologies of the synthesized particles were determined by TEM test. Under the uniform doping concentration, the energy transfer mechanism of different morphologies was studied, and the effect of particle morphology on the photo-temperature sensing was analyzed in detail. At the same time, the photo-temperature sensing properties of co-doped rare earth ion nanoparticles were studied when Yb was used as sensitizer, and different rare earth ions (REGRER) were used as activation ions. The results of TEM test show that the nanoparticles have good monodispersity. Comparing with the different co-doped nanoparticles under the optimum ratio, it can be seen that the co-doping of pr and Yb ions has more excellent Guang Min characteristics than other co-doping conditions, and has more potential in the application of Guang Min.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;TM914.4
本文编号：2184953
[Abstract]:Since the 21st century, with the rapid development of nanotechnology, rare-earth doped nanomaterials have attracted wide attention because of their excellent properties in light, electricity, magnetism and so on. Among them, the application of rare earth doped nanomaterials in enhancing solar energy efficiency and fluorescence temperature measurement has become a research hotspot. On the one hand, due to the small energy band gap (1.12eV) of the solar cell material itself, and the solar spectrum is a wide spectrum, a large part of the infrared and ultraviolet light in the solar light can not be absorbed and utilized by the cell. Therefore, the search for excellent spectral conversion materials has become a key factor to improve solar energy efficiency. Rare earth ion doped fluorides have been widely used in upconversion and downconversion luminescence due to their excellent optical conversion efficiency. High performance NaGdF4:12%Er3 and nanomaterials with core-shell structure were prepared by high temperature pyrolysis method. The results show that the synthesized NaGdF4:12%Er and NaGdF4:12%Er@Na GdF4:x%Er core-shell nanomaterials have good monodispersity and have homogeneous tetragonal and hexagonal structure respectively. By adjusting the erbium ion doping concentration in the shell layer of the nanoparticles, when the doping concentration in the shell layer reaches 10 mol%, compared with the monolayer nanoparticles, the fluorescence intensities of the core and shell nanoparticles doped with rare earth ions are 336 times higher than those of the monolayer nanoparticles. At the same time, according to the energy level structure of erbium ion, the fluorescence lifetime, the ratio of red and green light, and the width of half-maximum of the core-shell nanoparticles with different doping concentration were analyzed. Finally, the main up-conversion luminescence mechanism of erbium ion in the core-shell nanoparticles was obtained. On the other hand, due to the advantages of low external interference and strong anti-excitation power noise, the research of rare-earth doped nanomaterials in the field of fluorescence temperature measurement has gradually become a hot topic. In this paper, the hydrothermal method was used to adjust different reagents. Finally, six kinds of NaYF4:Er particles with different morphologies were synthesized, such as nanospheres, micron rods, hexagonal disks, spindles, microspheres and octahedron-like particles. The morphologies of the synthesized particles were determined by TEM test. Under the uniform doping concentration, the energy transfer mechanism of different morphologies was studied, and the effect of particle morphology on the photo-temperature sensing was analyzed in detail. At the same time, the photo-temperature sensing properties of co-doped rare earth ion nanoparticles were studied when Yb was used as sensitizer, and different rare earth ions (REGRER) were used as activation ions. The results of TEM test show that the nanoparticles have good monodispersity. Comparing with the different co-doped nanoparticles under the optimum ratio, it can be seen that the co-doping of pr and Yb ions has more excellent Guang Min characteristics than other co-doping conditions, and has more potential in the application of Guang Min.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;TM914.4
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