Systematic Investigation of Subtractive Contact Patterning for High- Resolution Organic Electronic Devices

We systematically investigated the mechanism of subtractive contact patterning (SCP) and demonstrated high resolution organic light-emitting diodes (OLEDs) using this SCP process. Owing to the application of the SCP process to various types of organic semiconducting thin films, crystalline thin films (e.g., pentacene) generated patterns via the delamination mechanism and amorphous small molecule thin films (e.g., tris(8-hydroxyquinolinato)aluminum) generated patterns via the diffusion mechanism. In the pattern generation via diffusion, we reported that the higher the processing temperature and the longer the processing time were, the deeper was the pattern depth. In particular, the patterning speed was proportional to the temperature in an exponential function. SCP can be applied to doped small molecule-based thin films and limitedly applied to polymer thin films. Finally, a high-resolution OLED pattern of less than 10 mu m wide was fabricated by applying the SCP process without any detrimental effects on the device performance. Furthermore, this SCP process was applied to flexible and curved thin films, which verified its potential use for roll-to-roll processes. This study provides a scientific and technological basis for the fabrication of high-resolution patterns of organic electronic devices such as OLEDs.