Fabrication of a large-area, flexible and color-neutral single-wall carbon nanotube:sodium dodecylbenzene sulfonate/poly-(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) transparent conductive film having a new conduction mechanism

Flexible transparent conductive films (TCFs) are vital to promote the development of flexible and foldable devices including touch panels, displays, organic solar cells, etc. We have prepared a large-area, flexible, and color-neutral single-wall carbon nanotube:sodium dodecylbenzene sulfonate/poly-(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (SWCNT:SDBS/PEDOT:PSS) composite TCF on a poly(ethylene terephthalate) substrate by a spray coating method. The TCF has a sheet resistance of 178 Ω sq−1 with 85% transmittance at 550 nm. The light transmission characteristics of the films can be tuned by changing the mass fraction of SWCNTs. When the mass fraction of SWCNTs is higher than 4 wt.%, the original blue tint of the TCFs has disappeared. More importantly, we find that SDBS may play a more important role than the SWCNT network in improving the electrical conductivity of the films by acting as a secondary dopant of PEDOT:PSS, which is different from the traditional understanding and existing explanation about the conduction mechanism of PEDOT:PSS-based composite films.