Direct Sub-Micrometer-Patterning of Conjugated Polymers and Polymer Light-Emitting Devices by Electron Beam Lithography

The lateral pattering of polymer light emitting devices (PLEDs) on the micro‐ and even sub‐micrometer level is a challenging task. Being able to fabricate devices with sub‐micrometer active device dimensions will, however, open new possibilities for fundamental studies as well as enable improvements in device performance. Therefore, in this study an electron beam‐based patterning method for conjugated polymers is evaluated, where the structuring is achieved by deliberate degradation and alteration of the molecular structure accompanied by a change in the emission properties. We find that the typical feature size accomplished with this method is approx. 2 µm for the active line width in PLEDs, while the in‐depth investigation of the structures shows that the lateral resolution is found to be approx. 500 nm. The most common deposition method for polymers is spin coating, a process that is not suitable for the production of patterned devices. By adding an electron beam lithography step to the device fabrication process, patterned light emitting polymer layers with features as small as 2 μm could be fabricated, and their applicability for patterned polymer light emitting devices could be demonstrated.