Printed transparent conducting electrodes based on carbon nanotubes (CNTs), reduced graphene oxide (rGO), and a polymer matrix.

Abstract: The main focus of this project was to prepare transparent and conductive electrodes (TCEs). TCEs were made out of multi-walled carbon nanotubes (MWCNTs), reduced graphene oxide (rGO), and polyvinylpyrrolidone (PVP). Based on the theoretical aspect, MWCNTs has emerged as a promising nanofiller in the polymer matrix due to its high electrical conductivity. As a nanofiller, MWCNTs were used with a small ratio of rGO with PVP as a polymer matrix in this project to prepare TCEs having low sheet resistance with high transparency. An appropriate amount of PVP has been shown to be a good combination with MWCNTs and rGO in the solvent to keep MWCNTs dispersed for a long time. Carboxyl group (-COOH) functionalized MWCNTs (FMWCNTs) was produced in a controlled oxidative procedure due to enabling good dispersion of FMWCNTs in water and ethanol solvents. In contrast, water dispersible rGO was chemically prepared by using GO and sodium borohydride where GO was produced from graphite by using improved Hummer's method. Drop casting and spray coating methods were applied to fabricate TCEswhere only water was used as the solvent for drop casted TCEs and a mixing ratio of water and ethanol was 70:30 as solvent for spray coated TCEs. It was also determined in this project that the spray coating method was more suitable for preparing TCEs rather than thedrop casting method due to easy fabrication, large area coating possibility, and the smoothness of the coated film surface. The sheet resistance was obtained as 5026 Ω/ ⃣  where the transparency was 65% in the case of the drop casted electrode for the ratio of rGO:FMWCNTs:PVP was 1.2:60:1 with 0.02 mg FMWCNTs. In the case of spray coated electrode at the same ratio of rGO:FMWCNTs:PVP, the sheet resistance was measured as 5961 Ω/ ⃣  where the transparency was 73%. But in the case of 60:1 mass ratio of FMWCNTs:PVP with 0.02 mg FMWCNTs, the sheet resistance was 7729 Ω/ ⃣  and transparency was 77% for spray coated electrode. So, it is clear that the sheet resistance was improved by adding a small mass ratio of rGO with FMWCNTs:PVP.