Inkjet Etching of Polymer Surfaces to Manufacture Microstructures for OLED Applications

A soluble polymer layer can be structured by means of solvent drops etching. The inkjet etching (IJE), innovative technique that consists of ejecting liquid material in controlled manner in terms of both volume amount (10–100 pL) and positioning on the substrate (μm resolution), allows to manufacture suitable shaped microstructures on top of polymer surfaces. In the present work we fabricated IJ etched polymer microstructures whose shape varies from concave to convex by employing a pure solvent or solvent mixtures with suitable mixing ratio of the solvents. The manufactured structure profile has been analyzed and the related geometrical parameters, i.e. depth, diameter and height, have been valuated as function of the drops number. Preliminary tests have been performed in order to employ the IJ etched polymer microstructures with the aim to improve the out‐coupling efficiency of organic light‐emitting diodes.