The Optoelectronic and Electrothermal Performances of Transparent Conductive Films Using Metal-Nanoparticle-Decorated Carbon Nanomaterials as Fillers

• Main Authors: Li, Yu-An, 李裕安
• Other Authors: 戴念華
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/33625704444105254109

博士 === 國立清華大學 === 材料科學工程學系 === 102 === In this work, we have developed a new transparent conductive films (TCFs) using carbon nanomaterials as conductive materials. The carbon nanomaterials included few-walled carbon nanotubes (FWCNTs) and graphene nanosheets (GNs). The TCFs made from carbon nanomaterials treated using functionalized process effectively enhanced the optoelectronic performance. The optoelectronic performance can be further enhanced by decorating metal nanoparticles on the surfaces of functionalized carbon nanomaterials, and we chose palladium (Pd) and silver (Ag) nanoparticles as decorating metal in this work. Extremely low sheet resistance of 274.0 ohm/sq of TCFs coated with Pd decorated onto functionalized FWCNT surfaces was attained, which was 1/25 the resistance exhibited by those coated with raw FWCNTs, whereas the same optical transmittance of 81.7% at a wavelength of 550 nm was maintained. To improve the TCF conductivity, we changed the dispersant to a conductive polymer, PEDOT:PSS, for decreasing the contact resistance between dispersant and carbon nanomaterials. In addition, we added two-dimentional GNs into one-dimentional FWCNTs to form three-dimentional conductive channels. Moreover, we coated Ag nanoparticles on the carbon nanomaterial surfaces to replace Pd nanoparticles because Ag possesses the highest electrical conductivity of metals. Besides, we developed a single step decorated process to coat Ag nanoparticles on the surfaces of carbon nanomaterials, it had more advantages such as simple, fast, and mass production available. When the mixture of 2.0 wt% of Ag decorated onto functionalized FWCNT surfaces and 8.0 wt% of Ag decorated onto functionalized GN surfaces containing PEDOT:PSS dispersant was coated onto a flexible plastic substrate, excellent optoelectronic properties with a sheet resistance of 53.0 ± 4.2 ohm/sq and a transmittance of 80.2 ± 0.8% at a wavelength of 550 nm were achieved. Using the TCFs to make flexible LED lights and flexible transparent film heaters showed more flexibility and good stability. Especially in electrothermal performances, the film possesses a high thermal conductivity of 142.0 ± 9.6 W/m-K, a quick response time of less than 60 s, stable heating performance, good reliability, low power consumption, flexibility, and uniform heat diffusion. In addition, the film shows an average infrared emissivity of 0.53 in the wavelength range of 4 to 14 μm, which shows an outstanding heat release performance by radiation. The flexible transparent film heaters adopting graphene and carbon nanotubes as fillers boast excellent electrothermal performance through heat conduction and infrared radiation, suggesting that they are good substitutes for traditional metallic and indium tin oxide film heaters.