Preparation of transparent conducting electrode on polysulfone film via multilayer transfer of layer-by-layer assembled carbon nanotubes

Transparent conducting electrode (TCE) were prepared on a flexible polysulfone (PSU) film with a multilayer transfer of multi-walled carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs) coated on glass substrates via layer-by-layer (LBL) deposition. First, bare CNTs were functionalized with carboxylic acid and amine moieties to obtain negatively and positively charged nanotubes, respectively. Second, functionalized CNTs were sequentially coated on a glass substrate via the LBL deposition, which was followed by subjecting the multilayer electrode to various chemical and thermal post-treatment processes to improve the electrical conductivity. Third, the multilayer was transferred from the glass substrate to the polymer film by coating and detaching the PSU. The highest figure of merit (FOM) was observed to be 2.52 × 10^− 6 Ω^− 1 at 68% optical transmission and 1.14 × 10^− 3 Ω^− 1 at 81% optical transmission for MWCNT and SWCNT films, respectively. Finally, the transparent electrode was demonstrated in a resistive touch sensor.