Inkjet-printed copper electrodes using photonic sintering and their application to organic thin-film transistors

We report on copper (Cu) electrodes fabricated with inkjet-printed nanoparticle inks that are photonic sintered on a polymer dielectric layer and their application to source and drain electrodes in organic thin-film transistor (TFT). By using photonic sintering with a radiant energy density of 9 J/cm², printed Cu nanoparticle layers on a glass substrate showed very low electrical resistivity levels of 7 μΩ cm. By optimizing the sintering conditions on polymer dielectric, the pentacene-based TFT using these printed Cu electrodes showed good mobility levels of 0.13 cm²/Vs and high on/off current ratios of about 10⁶. In addition, we revealed that the crystal grain growth of pentacene near the printed Cu electrodes was inhibited by the thermal damage of polymer underlayer due to the high radiant energy density of the intense light.