Solubility of Organic EL Pigments in Supercritical CO₂ and Effects of Entrainer Addition

Abstract

Metal masks used in the manufacturing of organic EL display units are thrown away after they are used once in the process because the organic EL pigments, which remains sticking to the masks, cannot be thoroughly removed. It was tried to use supercritical carbon dioxide for cleaning, but this resulted in insufficient elimination, and therefore, it was also tried to add entrainer to improve the solubility. In addition, trial was conducted to wash mimic metal masks, using supercritical carbon dioxide, which contains the added entrainer, in order to verify if this technique is feasible in practical use.