Optimizing Transparent Electrodes: Interplay of High Purity SWCNTs network and a Polymer

Abstract

The discovery of transparent electrodes led to the development of optoelectronic devices such as OLEDs, LCDs, touchscreens, IR sensors, etc. Since ITO has many drawbacks in respect of its production cost and limited transparency in IR, carbon nanotubes (CNTs) have been a potential replacement for ITO due to their exceptional electrical and optical properties, especially in the IR region. In this work, we present the development of a CNT-polymer composite thin film that exhibits outstanding transparency across both visible and IR spectra prepared by layer-by-layer (LbL) technique. This approach not only ensures uniform integration and crosslinking of CNTs into lightweight matrices, but also represents a cost-effective method for producing transparent electrodes with remarkable optical and electrical properties. The produced films achieved a transparency above 80% in the UV-VIS range and approximately 70% in the mid-IR range. The sheet resistance of the fabricated thin films was measured at about 4 kOhm/sq, showing a tendency to decrease with the number of bilayers. Furthermore, in this work we have investigated electrical properties and transport mechanisms in more detail with computational analysis. Computational analysis was performed to better understand the electrical behavior of nanotube-polymer junctions in the interbundle structure. Based on all results, we propose that the transparent electrodes with 4 and 6 bilayers are the most optimal structures in terms of optical and electrical properties.