Control of inkjet printed profiles by solvent-vapor annealing

The profile of colorant film produced in inkjet printing can be severely affected by the drying environment. This study found that a simple solvent-vapor annealing process can induce a drastic profile rearrangement of the subpixels on the entire substrate. The high surface tension and boiling point of the solvent play a critical role for the rearrangement to occur. The film surface is dissolved during the annealing process, and the high boiling point delays evaporation at the contact edge, which leads to the profile rearrangement. Due to the high surface tension of the solvent, the inks are confined inside the pixels. As a consequence, the profile becomes uniform without any outward color defect, regardless of the printed regions. This will be useful for organic electronics made by inkjet printing.