Synergistic Co-grafting of Multiwalled Carbon Nanotubes Using SO3H and Choline Chloride-Urea in Fabricating Uniform Thin Films with Enhanced Visible Light Transparency and Reduced Sheet Resistance

New materials and innovative modification methods are indispensable to advance the energy field. The present work reports the fabrication of transparent conducting electrodes using Multiwalled carbon nanotube (MWCNT) that have been modified with sulfonic acid (SO3H) and a combination of Choline Chloride-Urea/Sulfonic acid (DES/SO3H). A comprehensive investigation was conducted to ascertain the impact of employing DES and SO3H in achieving consistent and long-lasting dispersions of multiwalled carbon nanotubes in different solvents and the most favourable condition was achieved when employing n-heptanol. The films were fabricated on glass substrate by using the spray pyrolysis technique. The stability of the system following the modification was unequivocally confirmed by SEM analysis, while the electronic structure was assessed qualitatively by EDX analysis. Optical profilometry analysis revealed that the film thickness fell within the range of 350-385 nm. The co-grafted film demonstrated an optical transparency of approximately 84.96%, modestly exceeding that of the singly grafted film, which was determined to be 70.14% in the visible region. The sheet resistance of DES/S-MWCNT and S-MWCNTs was calculated to be approximately 3.33k Omega/Sq and 5.02k Omega/Sq, respectively. The calculated charge transfer resistance (RCT) for the co-grafted and singly grafted MWCNT systems was 0.185 Omega and 0.190 Omega, respectively. These values align closely with the corresponding sheet resistance values obtained. The electrochemical investigations also showed an increased specific capacity for DES/S-MWCNT, approximately 896.2C/g, whereas the calculated value for the S-MWCNT system was 826.8C/g.