石墨烯量子点与纳米粒子复合物的制备及性能测试

发布时间：2018-02-13 01:19

  本文关键词： 石墨烯 纳米粒子 石墨烯量子点 复合材料 热电　出处：《西北大学》2015年硕士论文　论文类型：学位论文

【摘要】：纳米材料由于其纳米尺度强烈的量子限域效应和灵活的尺寸调节,引起了科学家们广泛的研究。作为碳材料的一种石墨烯量子点(GQD)拥有和石墨烯相同的结构,在高温下其内部结构能够很好地保持稳定,加之其较小的尺寸和大量的边缘含氧官能团,因此可以类似的将GQD看作为表面修饰剂与纳米粒子进行复合。根据此原理,本论文利用GQD表面含有大量的含氧官能团,将其与半导体纳米粒子进行复合,并对其光学、电学和热电性质进行研究。同时由扫描电子显微镜图和X-多晶粉末衍射图发现石墨烯量子点显著地减弱了热电纳米粒子在等立体高温烧结过程中的融合。我们通过热注射法成功的合成了尺寸在纳米级别且较为均一的无机纳米粒子。与此同时,通过对石墨烯进行深度氧化处理并进一步氧化切割,得到了尺寸较小的石墨烯量子点。再对纳米粒子表面配体和溶剂的替换,使石墨烯量子点作为配体的与半导体纳米粒子进行复合。通过对复合前后的纳米粒子进行对比,我们发现复合后的材料导电率有了较大幅度的提高,并且通过光学的研究发现复合材料发生了能量传递。接下来我们对石墨烯量子点与纳米粒子的复合材料进行了热电性能的研究。将交换完配体的复合纳米粒子在200℃管式炉中进行充分干燥,再经过等离子体高温烧结热压(SPS)成片。对最终的产物进行表征和测试,一系列光谱发现石墨烯量子点依然存在,且较好的控制了纳米热电材料在高温区的融合。对材料进行热电性能的测定,也得到了相对较高的热电优值(ZT)。
[Abstract]:Nanomaterials have been widely studied by scientists due to their strong quantum limiting effect and flexible size adjustment at nanoscale. As a carbon material, graphene quantum dots (GQDs) have the same structure as graphene. At high temperature, its internal structure is very stable, coupled with its small size and a large number of edge oxygen functional groups, so it can be similar to the GQD as a surface modifier and composite nanoparticles. In this paper, the surface of GQD containing a large number of oxygen-containing functional groups, the composite with semiconductor nanoparticles, and its optical, The electrical and thermoelectric properties were studied. At the same time, it was found from the scanning electron microscopy and X-ray powder diffraction that graphene quantum dots significantly weakened the fusion of thermoelectric nanoparticles in the process of isostereoscopic high temperature sintering. The superheated injection method successfully synthesized inorganic nanoparticles of a more uniform size at the nanoscale. At the same time, By advanced oxidation and further oxidation of graphene, smaller graphene quantum dots were obtained, and then the ligands and solvents were replaced on the surface of nanoparticles. The graphene quantum dots are used as ligands to combine with semiconductor nanoparticles. By comparing the nanoparticles before and after the composite, we find that the conductivity of the composite materials has been greatly improved. Then we study the thermoelectric properties of the composites of graphene quantum dots and nanocrystalline particles. Fully drying in 200 鈩，

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