| Summary: | 碩士 === 國立臺南大學 === 材料科學系碩士班 === 99 === At present the most common material in the transparent conductive films is the tin doped indium oxide (ITO), because ITO has the high transmittance as well as good electrical property. However, ITO has certain problems, mainly centered on its scarcity of supply. Researchers have tried to develop new transparent conductive materials to replace ITO, such as carbon nanotube, graphene, and silver nanowires. In our study, the aim is to prepare and evaluate the films of silver nanowires, graphene, and their mixtures for the application as transparent conductive films.
This paper will be divided into two major parts: the synthesis of silver nanowires, graphene and their hybrid materials, and the preparation and characterization of transparent conductive thin films both on the glass and flexible substrates. First, we used the polyol method to synthesize silver nanowire with sodium chloride (NaCl) as the precursor for seeds. The experimental results show that the different seeds used, the concentration of reactants, and the addition rate of silver nitrate will affect the growth characteristics of silver nanowires. SEM, UV-vis spectra and XRD have been employed to characterize the silver nanowires. This study successfully prepared silver nanowires with a diameter of 100 nm and a length of 17 μm, and the films prepared using the nanowires can have a transparency of 83 % and a sheet resistance of 11 Ω/sq.
Next, the Hummer’s method is used to prepare the graphite oxide, and hydrazine is used to obtain reduced graphene oxide solution. We further varied the solid concentration and deposition density to prepare graphene thin films, and then improved the conductivity of thin films by a heat treatment step. We obtain graphene films with a transparency of 80 % and a sheet resistance of 90 kΩ/sq.
And then, we mixed the silver nanowire and graphene suspensions to form hybrid materials with different ratios. The obtained films show a transmittance of 77.6 %and a sheet resistance of 17.8 Ω/sq.
Finally, this study further used polyvinyl alcohol(PVA), polyamide acid(PAA) and polydimethyl siloxane(PDMS) as substrates to prepare flexible transparent conductive films. The hybrid thin films prepared on the PVA flexible substrates can have a transparency of 78.2 % and a sheet resistance of 18.8 Ω/sq.
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