When using metal nanoparticles as a material for conductive nanoink for inkjet use, it is necessary to carefully consider surface protection of the metal nanoparticles. This is because while surface protection is essential for metal nanoparticles when they are dispersed in liquid, at the stage of coating and drying to form a conductive coating, the stabilizer on the nanoparticle surface is a factor that inhibits conductivity. We have been the first in the world to report on pi-junction metal nanoparticles that are stabilized by planar coordination of planar pi-conjugated molecules such as porphyrin and phthalocyanine. In particular, it has been demonstrated that pi-junctions can stably disperse metal nanoparticles in liquids using extremely small amounts of molecules. The fact that only a small amount of molecules are required to protect the nanoparticles is directly linked to the fact that the conductivity after coating and drying is advantageous.
By utilizing the above properties, conductive nanoink for inkjet using pi-junction metal nanoparticles satisfies several important properties that were previously impossible, and is actually used in mass production in industry. This time, I will explain the factors that led to this.