| abstract |
A composition suitable for printing of an opto-electrical device, comprises a semiconducting hole transport material, a first solvent and a second solvent, the first solvent being 1-tetralone, benzylbenzoate and 1 methoxynaphthalene o-xylene, mixed-xylene, ethylbenzene, propylbenzene, butylbenzene having a higher boiling point and a greater viscosity than the second solvent, the second solvent being mesitylene, o-xylene, mixed-xylene, ethylbenzene, propylbenzene, butylbenzene. The solvents are miscible with one another and the viscosity of the first solvent is in the range of 5 to 12 mPas. The first solvent has a boiling point between 250 and 350 °C, and the second solvent has a boiling point between 100 and 200 °C. The figure shows derived interlayer film profiles when printed onto PEDOT (PD239). The old formulation shows edge thickening whereas two new formulations give slight edge thinning. |