Length-controlled few-walled carbon nanotubes and their effect on the electrical property of flexible transparent conductive films

Abstract

We investigated the effect of the length of carbon nanotubes (CNTs) on the electrical property of CNT-based flexible, transparent, and conductive films (TCFs). We grew vertically aligned CNTs with controlled lengths, dispersed them in ethanol by ultrasonication, and spray coated them onto polyethylene terephthalate (PET) sheets. We focused on the variation in the sheet resistance and transmittance of the above-mentioned films as a function of the CNT length, and we found that the optimum CNT length was 200 µm. We concluded that the CNT length should be carefully optimized because a shorter tube affords the advantage of efficient dispersion, while a longer tube helps in reducing the number of contact points between tubes along the electrical conduction path.

An edge-decorated submicron reduced graphite oxide nanoflake and its composites with carbon nanotubes for transparent conducting films

“…1,2 Carbon-based TCFs, carbon nanotubes (CNTs) and graphene in particular, have received increasing attention due to their outstanding mechanical, optical, and electrical properties. [2][3][4][5][6][7][8] However, for pure graphene or CNTs lms, excellent electrical conductivity and light transmittance are difficult to achieve at the same time. 8,9 The main reasons include the presence of voids in spiderweb-like network structure of CNTs 9 and high intersheet contact resistance among small-size graphenes.…”

“…This trend is consistent with pure CNT or graphene lms. 7,8 We measure the thickness of the lm with 84% transmittance by AFM (Fig. 5).…”