| abstract |
An ink composition suitable for printing optoelectronic devices comprises a semiconducting hole transport material, a first solvent and a second solvent, the first solvent having a higher boiling point and a greater viscosity than the second solvent. The solvents are miscible with one another. The first solvent has a boiling point of between 250 and 350°C and the second solvent has a boiling point of between 100 and 200°C. The viscosity of the first solvent is in the range of 5 to 12 MPas. The first solvent may be 1-tetralone, benzylbenzoate and 1 methoxynapthalene o-xylene, mixed xylene, ethylbenzene, propylbenzene, and butylbenzene. The second solvent may be mesitylene, o-xylene, mixed-xylene, ethylbenzene, propylbenzene, and butylbenzene. |