Posted on 07 Oct 14:39
Following on from our post about the Innovate UK grant and what we achieved during the project, we thought we would give a behind the scenes look at one of the most exciting products to come out of it. The Ossila Slot Die Coater, launching in early 2016, will be an invaluable tool for up scaling cutting edge OLEDs, OPVs, OFETS, sensors and inorganic solar cells.
Spin coating is a commonly used tool in coating application and device manufacture, and our Spin Coater is one of our best selling products. Spin coating offers a large amount of control when creating organic electronic devices due to its well understood mechanics, its small scale batch production, and tight control of variables in repeatability through programs. However, spin coating has its limitations. It is difficult to coat substrates larger than 50 mm2 with the same control as smaller ones, it's a batch process, you are only able to coat one device at once. It is also not a compatible process with roll-2-roll manufacturing, the simplest way to scale up flexible electronics research.
These inherent qualities of spin coating prevent it from being a suitable method for commercialisation and scale up. Investigating alternative deposition techniques can introduce additional problems when fabricating devices, whether from the different deposition process or a different device size. This requires a significant investment in time and can be costly due to the required equipment and the amount of materials consumed per experimental run.
During the Innovate UK grant, we intended to make an instrument that would change this and enable investigations into high throughput coating techniques in the lab. Three criteria were identified for the unit to be lab ready; it had to create production quality coatings, be affordable, and be compact.
We initially looked at making a blade coater, with the aim of using 3D printed micro-patterned blade heads. Having seen research by Diao et al.1 into micro-patterned blade heads manufactured using nano lithography, we investigated the prospect of creating the blade heads using high resolution 3D printing. The patterning controls the flow of the coating material and creates uniform crystallinity. Unfortunately current 3D printing techniques are not able to create patterns of the required size and quality to allow for production of the blade heads.
After this set back, our attention turned to slot die coating. Slot die coating is a deposition method used in roll-2-roll manufacture, where the head deposits the ink material without contacting the substrate. The meniscus formed between the head and the substrate acts as the paintbrush, with coating thickness controlled by the flow rate of the material and the speed of the relative linear motion of the head.
To give a sneak peek behind the design process at Ossila, and give you an overview of the challenges we faced in the project, we have gathered a selection of images from the development of the prototype Slot Die Coater.
It is important to note that the development process has not yet finished. We are currently working on optimisation and user friendliness of the unit, and the complete feature list has not yet been finalised. If you have any suggestions, or specific requirements for what you would like the Slot Die Coater to do, please contact us.