本文關鍵詞： 石墨烯 納米粒子 石墨烯量子點 復合材料 熱電　出處：《西北大學》2015年碩士論文　論文類型：學位論文

【摘要】：納米材料由于其納米尺度強烈的量子限域效應和靈活的尺寸調節(jié),引起了科學家們廣泛的研究。作為碳材料的一種石墨烯量子點(GQD)擁有和石墨烯相同的結構,在高溫下其內部結構能夠很好地保持穩(wěn)定,加之其較小的尺寸和大量的邊緣含氧官能團,因此可以類似的將GQD看作為表面修飾劑與納米粒子進行復合。根據(jù)此原理,本論文利用GQD表面含有大量的含氧官能團,將其與半導體納米粒子進行復合,并對其光學、電學和熱電性質進行研究。同時由掃描電子顯微鏡圖和X-多晶粉末衍射圖發(fā)現(xiàn)石墨烯量子點顯著地減弱了熱電納米粒子在等立體高溫燒結過程中的融合。我們通過熱注射法成功的合成了尺寸在納米級別且較為均一的無機納米粒子。與此同時,通過對石墨烯進行深度氧化處理并進一步氧化切割,得到了尺寸較小的石墨烯量子點。再對納米粒子表面配體和溶劑的替換,使石墨烯量子點作為配體的與半導體納米粒子進行復合。通過對復合前后的納米粒子進行對比,我們發(fā)現(xiàn)復合后的材料導電率有了較大幅度的提高,并且通過光學的研究發(fā)現(xiàn)復合材料發(fā)生了能量傳遞。接下來我們對石墨烯量子點與納米粒子的復合材料進行了熱電性能的研究。將交換完配體的復合納米粒子在200℃管式爐中進行充分干燥,再經(jīng)過等離子體高溫燒結熱壓(SPS)成片。對最終的產物進行表征和測試,一系列光譜發(fā)現(xiàn)石墨烯量子點依然存在,且較好的控制了納米熱電材料在高溫區(qū)的融合。對材料進行熱電性能的測定,也得到了相對較高的熱電優(yōu)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，

本文編號：1506997