Spin and dip coating of light-emitting polymer solutions: Matching experiment with modelling

This paper reports experimental observations on spin and dip coating of light-emitting polymer (LEP) solutions where both the process conditions as well as the solution properties are factors influencing thickness and uniformity of thin LEP films. In terms of spin coating, which is a typical process for the manufacture of polymer light-emitting diodes (PLEDs), a number of process variables including spin speed were systematically explored. A matching series of dip-coating experiments was also carried out with the retraction speed as a primary variable. Modifications of existing models for both spin and dip coating were developed to include solvent evaporation and the effect of solution viscosity change during evaporation. Both models were found to give reasonable agreement with the major observed trends for final film thickness as a function of process conditions tested in this paper. (c) 2006 Elsevier Ltd. All rights reserved.