New Slot-Die Coating Guide Available: Troubleshooting Defects

Posted on Thu, Jan 25, 2018 by Jon Griffin

An extremely versatile deposition technique, slot-die coating is capable of being integrated into both roll-to-roll and sheet-to-sheet deposition systems. Slot-die coating's key advantage is its simple relationship between i) wet-film coating thickness, ii) the flow rate of solution, and iii) the speed of the coated substrate relative to the head. Moreover, it can achieve extremely uniform films across large areas - in the best cases with variation being less than 1% across several meters. 

Figure 1. The stable coating window for slot-die coating allows for defect-free films. By tuning processing parameters, it can be returned to the stable coating window.


However, despite the many advantages of slot-die coating, there are a few technical challenges that make it slightly more difficult compared to standard coating techniques (e.g. spin coating). These challenges arise from the need for pressure to be balanced at varying interfaces, so that the coating process can form a stable meniscus. Coating must be done within a stable window for it to be defect-free, and the variation of one of many parameters can steer the coating process away from this stable coating region.

Ossila have created a new guide to help you troubleshoot any slot-die coating issues you may face in your research. In this guide, we hope to introduce the idea behind the stable coating window that slot-die coating operates within, and relate this to observable defects that can occur within the film. By knowing how the processing window relates to coating parameters, it is possible to vary these to return to the stable processing region and remove defects from your coatings.



Author: Jon Griffin

Jonathan joined Ossila in July 2016 after working as a post-doctoral research associate at the University of Sheffield. During his career as a research scientist, he has worked in a wide range of areas including organic light-emitting diodes, organic photovoltaics, transparent conductors, organic lead-halide perovskites, and scale-up processes in thin-film fabrication. As part of his role at Ossila, Jonathan is responsible for the technical support for several material ranges, including perovskites, organic photovoltaics, graphene and other 2-D materials. In addition, he is also involved in the development of new equipment and product ranges.