Fabrication of Graphene Conductine Thin Films by Self-Assembly and Reduction of Graphene Oxide Sheets

• Main Authors: Chao-Guang Huang, 黃朝光
• Other Authors: Nen-Wen Pu
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/59297521216796756629

碩士 === 元智大學 === 光電工程學系 === 101 === The thesis aims to examine the effects of the graphite oxide (GO) size and reduction formula on the characteristics of the reduced graphene transparent conductive films (TCFs), which were fabricated by using natural graphite as the raw material to produce a GO membrane using a chemical oxidation method combined with thin film self-assembly, followed by a reduction process and a post treatment step to form a TCF. The experiments were divided into two parts. Part one studied the impact of GO sheet’s size and the GO/organic solvent’s content ratio on the performance of the graphene TCFs. By using XRD and TEM, GO’s interlayer distance and particle size can be observed. The sheet resistance and optical transmission were measured with a four-point probe and UV-Vis, respectively. The results showed that larger GO sheets can be derived from 10-mesh graphite using the Hummers method. A GO/DMF(organic solvent) mixing ratio at 0.015g/75ml gives the GO film the highest light transmission (~93% at 550 nm), and an optimal sheet resistance of 5.8 k/sq and optical transmission of 82% was obtained after the GO film was reduced to graphene TCF using ascorbic acid as the reductant. Part two of the experiments compare the performances of various reducing agents and post treatment methods for improving the electrical conductivity of the TCFs. It was found that hydrogen iodide, when compared with Vitamin C, hydrazine, hydrazine vapor, exhibited the best performance (with a sheet resistance of 3.5 k/sq, and transmission of 83%). Observation using SEM, XPS showed that graphene TCF’s surface roughness and oxygen-containing functional groups have been significantly reduced. Lastly, post-treatment of the graphene TCFs using nitric acid (HNO3) or thionyl chloride (SOCl2) can further reduce the sheet resistance to ~1.9 k/sq with optical transmission of 81%. The results confirmed that we are able to achieve the goals of fabricating graphene TCFs with a low sheet resistance and a simple and low-cost process.