Slot-die coating

A simple cross-section schematic of the slot-die coating process.

Slot-die coating is a coating technique for the application of solution, slurry, hot-melt, or extruded thin films onto typically flat substrates such as glass, metal, paper, fabric, plastic, or metal foils. The process was first developed for the industrial production of photographic papers in the 1950's.[1] It has since become relevant in numerous commercial processes and nanomaterials related research fields.[2][3][4][5][6][7]

Slot-die coating produces thin films via solution processing.[8] The desired coating material is typically dissolved or suspended into a precursor solution or slurry (sometimes referred to as "ink") and delivered onto the surface of the substrate through a precise coating head known as a slot-die. The slot-die has a high aspect ratio outlet controlling the final delivery of the coating liquid onto the substrate. This results in the continuous production of a wide layer of coated material on the substrate, with adjustable width depending on the dimensions of the slot-die outlet. By closely controlling the rate of solution deposition and the relative speed of the substrate, slot-die coating affords thin material coatings with easily controllable thicknesses in the range of 10 nanometers to hundreds of micrometers after evaporation of the precursor solvent.[9]

Commonly cited benefits of the slot-die coating process include its pre-metered thickness control, non-contact coating mechanism, high material efficiency, scalability of coating areas and throughput speeds, and roll-to-roll compatibility. The process also allows for a wide working range of layer thickness and precursor solution properties such as material choice, viscosity, and solids content.[10][11][12][13][14] Commonly cited drawbacks of the slot-die coating process include its comparatively high complexity of apparatus and process optimization relative to similar coating techniques such as blade coating and spin coating. Furthermore, slot-die coating falls into the category of coating processes rather than printing processes. It is therefore better suited for coating of uniform, thin material layers rather than printing or consecutive buildup of complex images and patterns.

  1. ^ US 2681294, Beguin, Albert E., "Method of coating strip material", issued 1951-08-23, assigned to Eastman Kodak Co. 
  2. ^ Vijayan, Anuja; Johansson, Malin B.; Svanström, Sebastian; Cappel, Ute B.; Rensmo, Håkan; Boschloo, Gerrit (2020-05-26). "Simple Method for Efficient Slot-Die Coating of MAPbI3 Perovskite Thin Films in Ambient Air Conditions". ACS Applied Energy Materials. 3 (5): 4331–4337. doi:10.1021/acsaem.0c00039. PMC 7493223. PMID 32954222.
  3. ^ Schmitt, Marcel; Baunach, Michael; Wengeler, Lukas; Peters, Katharina; Junges, Pascal; Scharfer, Philip; Schabel, Wilhelm (2013-06-01). "Slot-die processing of lithium-ion battery electrodes—Coating window characterization". Chemical Engineering and Processing: Process Intensification. Advances in Coating and Drying of Thin Films. 68: 32–37. Bibcode:2013CEPPI..68...32S. doi:10.1016/j.cep.2012.10.011. ISSN 0255-2701.
  4. ^ Dixon, Christopher; Ng, Alphonsus H. C.; Fobel, Ryan; Miltenburg, Mark B.; Wheeler, Aaron R. (2016-11-15). "An inkjet printed, roll-coated digital microfluidic device for inexpensive, miniaturized diagnostic assays". Lab on a Chip. 16 (23): 4560–4568. doi:10.1039/C6LC01064D. ISSN 1473-0189. PMID 27801455.
  5. ^ Wester, Niklas; Mikladal, Bjørn F.; Varjos, Ilkka; Peltonen, Antti; Kalso, Eija; Lilius, Tuomas; Laurila, Tomi; Koskinen, Jari (2020-10-06). "Disposable Nafion-Coated Single-Walled Carbon Nanotube Test Strip for Electrochemical Quantitative Determination of Acetaminophen in a Finger-Prick Whole Blood Sample". Analytical Chemistry. 92 (19): 13017–13024. doi:10.1021/acs.analchem.0c01857. ISSN 0003-2700. PMC 7547857. PMID 32842738.
  6. ^ Zuo, Jialin; Tavakoli, Sean; Mathavakrishnan, Deepakkrishna; Ma, Taichong; Lim, Matthew; Rotondo, Brandon; Pauzauskie, Peter; Pavinatto, Felippe; MacKenzie, Devin (June 2020). "Additive Manufacturing of a Flexible Carbon Monoxide Sensor Based on a SnO2-Graphene Nanoink". Chemosensors. 8 (2): 36. doi:10.3390/chemosensors8020036.
  7. ^ Park, Janghoon; Shin, Keehyun; Lee, Changwoo (2016-04-01). "Roll-to-Roll Coating Technology and Its Applications: A Review". International Journal of Precision Engineering and Manufacturing. 17 (4): 537–550. doi:10.1007/s12541-016-0067-z. ISSN 2005-4602. S2CID 138667468.
  8. ^ Eslamian, Morteza (2016-09-08). "Inorganic and Organic Solution-Processed Thin Film Devices". Nano-Micro Letters. 9 (1): 3. doi:10.1007/s40820-016-0106-4. ISSN 2150-5551. PMC 6223778. PMID 30460300.
  9. ^ "Discover slot-die coating". FOM Technologies. Retrieved 2020-12-09.
  10. ^ "Printing, coating, metering & the slot-die process". FOM Technologies. 2021-11-15. Retrieved 2021-12-17.
  11. ^ Ding, Xiaoyu; Liu, Jianhua; Harris, Tequila A. L. (2016). "A review of the operating limits in slot die coating processes". AIChE Journal. 62 (7): 2508–2524. Bibcode:2016AIChE..62.2508D. doi:10.1002/aic.15268. ISSN 1547-5905.
  12. ^ Merklein, Lisa; Daume, Dominik; Braig, Felix; Schlisske, Stefan; Rödlmeier, Tobias; Mink, Marvin; Kourkoulos, Dimitrios; Ulber, Benjamin; Di Biase, Manuela; Meerholz, Klaus; Hernandez-Sosa, Gerardo (March 2019). "Comparative Study of Printed Multilayer OLED Fabrication through Slot Die Coating, Gravure and Inkjet Printing, and Their Combination". Colloids and Interfaces. 3 (1): 32. doi:10.3390/colloids3010032.
  13. ^ Burkitt, Daniel; Searle, Justin; Worsley, David A.; Watson, Trystan (November 2018). "Sequential Slot-Die Deposition of Perovskite Solar Cells Using Dimethylsulfoxide Lead Iodide Ink". Materials. 11 (11): 2106. Bibcode:2018Mate...11.2106B. doi:10.3390/ma11112106. PMC 6265966. PMID 30373145.
  14. ^ Cohen, Edward D.; Gutoff, Edgar B., eds. (1992). Modern coating and drying technology. New York: VCH. ISBN 1-56081-097-1. OCLC 25411754.