Triangular geometry assisted spontaneous molecular alignment on patterned layer in solution-processed transistors

We demonstrate a triangular geometry assisted method to induce self-alignment of organic semiconductor molecule in a patterned layer. Angle of an oblique side in triangular geometry is systemically controlled to generate a more spontaneously aligned film on the basis of understanding the mechanism of film growth characteristics. As results, gradient of solvent density is formed, and slow solvent evaporation and unidirectional solvent diffusion are induced effectively in geometry up to angle of 10^°. However, over the angle of 10^°, the effect of triangular geometry is not applied due to sufficient space for solvent evaporation, and semiconductor film is exhibited as same as reference. These effects under the angle of 10^° tune the charge transport characteristic of semiconductor thin film, and triangular geometry applied organic thin film transistors (OTFTs) exhibited a fivefold increased field-effect mobility compared with the conventional OTFTs.