Slot die coating is a very versatile deposition technique in which a solution is delivered to the substrate through narrow slots close to the surface.
A major advantage of the slot die coating method is the simple relationship between wet film coating thickness, solution flow rate, and velocity of the coated substrate relative to the head. In addition, slot die coating enables very uniform films over large areas.
Slot die coating is one of many methods that can be used to deposit thin liquid films onto substrate surfaces. One of the key advantages of slot die coating over traditional techniques such as spin coating or dip coating is that it can be easily integrated into scale-up processes, including roll-to-roll coating and sheet-to-sheet deposition systems.
The technology itself provides a high level of coating uniformity over the length/width of the coated surface and can deposit films with thicknesses ranging from a few nanometers to a few microns. It can do this for a wide range of solution types and viscosities at rates ranging from centimeters per second to meters per second.
Slot die coating is part of a family of techniques classified as pre-metered coating techniques. For premetered deposition, the film thickness depends on the rate at which the solution is passed through the system. This makes the theoretical determination of wet film thickness very easy compared to other methods.
Because slot-die coating offers an excellent processing window compared to other roll-to-roll compatible techniques, this method is of great interest to researchers transitioning from laboratory-scale thin film fabrication to pilot-scale production. Researchers in polymer and perovskite photovoltaics, organic light-emitting diodes, quantum dots, and photonic structures (among many others) are now focusing on applying slot-die coatings as a deposition technique in their research to determine the feasibility of transferring Their material and device structure to a scale-up process.
