Electrical properties of transparent CNT and ITO coatings on PET substrate including nano-structural aspects

► Transparent CNT and ITO coatings were fabricated by spray-coating. ► The concentration of coating suspension was used to easily control coating thickness. ► Spray-coating has the advantage of simple process and large deposition areas. ► Highly transparent and conductive CNT and ITO coatings could be fabricated. ► CNT coatings exhibited better interfacial durability than brittle ITO coatings. Ultraviolet (UV)–visible spectra and surface resistance measurement were used to investigate optical transmittance and conductive properties of carbon nanotube (CNT) and indium tin oxide (ITO) coated polyethylene terephthalate (PET) substrates. Conductive CNT and ITO coatings were successfully fabricated on PET by a spray-coating method. Thin coatings of both materials exhibited good conductivity and transparency. Changes in electrical and optical properties of the coatings were studied as a function of the coating suspension concentration. Interfacial durability of the coatings on PET substrates was also investigated under fatigue and bending loads. CNT coated substrates, with high aspect ratios, exhibited no detectable change in surface resistance up to 2000 cyclic loadings, whereas the ITO coated substrates exhibited a substantial increase in surface resistance at 1000 loading cycles. This change in resistance is attributed to a reduction in the number and effectiveness of the electrical contact points due to the inherent brittle nature of ITO.