Directly patterned ITO nanoparticle-based transparent electrode using co-solvent-based aerosol jet printing for transparent thin film heaters

Abstract

High-performance transparent thin film heaters (TFHs) employing cost-effective nanoparticle-based transparent electrodes have attracted significant attention for applications in multifunctional smart windows. This study demonstrates the fabrication of high-performance TFHs featuring directly patterned Sn-doped In2O3 (ITO) nanoparticle electrodes using a methanol and ethylene glycol co-solvent-based aerosol jet printing (AJP) process. Our method utilizes a co-solvent ITO nanoparticle solution, blending methanol and ethylene glycol, to improve the surface uniformity and roughness of the AJP-processed ITO nanoparticle electrodes. The optimization of these electrodes was assessed using the figure of merit (FoM=T10/Rsh) value, derived from the transparency and sheet resistance of the electrodes. As a result of the AJP process and post-annealing optimization, the directly patterned ITO nanoparticle electrodes exhibited a high FoM value of 16.1 Ω−1, attributed to a high optical transmittance of 90.6 % and low sheet resistance of 23.20 Ω/sq. These optimized ITO nanoparticle electrodes were subsequently applied to TFHs through precise patterning of ITO electrodes via AJP. The ITO nanoparticle-based TFHs, benefiting from superior conductivity and precise AJP patterning, demonstrated a saturation temperature of 118.2 °C when subjected to a voltage of 9 V. Thermal stability and uniformity tests showed a temperature deviation of less than 5 %, validating the reliability of the TFHs. The performance of the AJP-processed ITO nanoparticle-based TFHs highlights the feasibility of cost-effective transparent TFHs for multifunctional smart windows, showing potential applications in electric vehicles and next-generation smart buildings.