Fabrication of Mesh-Patterned Transparent Heater using Large-Sized Sheets of Reduced Graphene Oxide

Abstract

Transparent heaters are widely used for defrosting to improve visibility, insulation or heating of buildings, and thermal treatment. Indium tin oxide (ITO), which has excellent transmittance and electrical conductivity, is one of the representative materials used for these transparent heaters. However, it has several drawbacks including high material price, limited processability in large-area, and brittleness. Here, we fabricated a mesh-patterned transparent heater utilizing an inexpensive and solution-processable material, reduced graphene oxide, as an alternative to ITO. In this study, electrical conductivity was improved by the synthesis of large-sized reduced graphene oxide (LrGO). Over 80% of transmittance was obtained by adapting mesh patterns. Moreover, to alleviate the decrease in transmittance due to diffraction by the mesh pattern, transparent heaters were prepared with six different mesh patterns by changing the space between the repeating pattern units. Comparing the transmittance values from calculations and measurements, the HH (honeycomb-honeycomb) mesh pattern was determined to have the minimum degradation of transmittance due to diffraction. In addition, the electrical/optical properties and heating performances of LrGO meshpatterned transparent heaters were compared to confirm the optimal mesh pattern. As a result, frost was completely removed within 30 seconds under a low power of 0.07 W using a H-H 85% mesh patterned heater.