High optoelectronic performance of layer-by-layer assembled carbon nanotube thin films as transparent electrodes for LC cell

Abstract

Highly transparent and conductive thin films were assembled as a potential indium tin oxide (ITO) replacement using layer-by-layer (LbL) assembly with carbon nanotubes (CNTs), sodium deoxycholate (DOC) as a stabilizer and poly(diallyldimethyl ammonium chloride) [PDDA] as polycations. This LbL adsorption of both species has linear increase independent on number of bilayers deposited. The self-assembly of DOC-stabilized CNTs and PDDA was shown to realize the thinner and smoother films with transparency (<84% T) and electrical conductivity (~300 Ω/sq) with a 23.5 nm thickness. Moreover, nitric acid doping was also treated for higher conductivity (~104 Ω/sq) due to the removal of insulating materials and the charge transfer doping. The optoelectronic performance of 5 BL DWNT LbL film here is much better than most other CNT thin films and capable of the ITO replacement. Then, the CNT LbL thin films were applied to fabricate liquid crystal (LC) cells as transparent electrodes. Voltage-transmittance performance exhibited the availability of a CNT LbL electrode to LC display. Additionally, the bending stability could suggest that these films potentially be used in a variety of electronic applications. Also, the ability to tailor thin film resistance can be potentially useful for anti-static films and EMI shielding.