| abstract |
A printing ink composition, comprising a functional material and a solvent, the solvent can be evaporated from the printing ink composition to form a functional material film; the solvent is formed by mixing at least two organic solvents, and the two organic solvents are a first solvent and a second organic solvent. The solvent, the first solvent and the second solvent are mutually miscible, the boiling point of at least one organic solvent in the first solvent and the second solvent is greater than or equal to 160°C, the surface tension of the second solvent is smaller than that of the first solvent, and the viscosity of the second solvent is greater than that of the first solvent. The solvent, the difference in surface tension between the first solvent and the second solvent is at least 2 dyne/cm, and the difference in viscosity between the second solvent and the first solvent is at least 2 cPs. The above-mentioned solvent system containing at least two organic solvents can dissolve functional materials more effectively without adding additives, and can also effectively prevent the occurrence of "coffee ring effect", so that a film with uniform thickness and strong charge transport capability can be obtained. |