Formation of conductive layers based on carbon nanotubes by the Langmuir method

The compression isotherm and potential jump methods were used to study Langmuir monolayers formed from individual solutions of carbon nanotubes (CNTs) and their mixtures with arachidic acid (AA) in various ratios. The optimal amount of CNT solution (200 μL) for forming a Langmuir layer was empirically found. When transferred to a solid substrate, the layer has an average conductivity of about 4.3⋅10–12 S⋅sq–1. It was also found that when applying the second and subsequent layers, the film conductivity increases by more than 6 orders of magnitude (up to 5.08⋅10–6 S⋅sq–1). In the study of mixtures of carbon nanotube solutions (without amphiphilic properties) and arachidic acid (a typical representative of a surfactant), an optimal ratio of the volumes of the prepared solutions was found (CNT : AA – 80 : 20), at which it is possible to control the degree of compression of the carbon nanotube layer on the surface of the aqueous subphase. It was shown that the introduction of AA molecules into the composition of CNTs allows an additional increase in the films conductivity by more than two orders of magnitude (up to 1.18⋅10–3 S⋅sq–1), compared to films of individual CNTs. The studied films can be used as a platform for the creation of various devices for micro- and nanoelectronics, optoelectronics, photovoltaics and flexible electronics.