Screen Printable Electroluminescent Polymer Ink

Abstract

The addition of a variety of additives to a soluble electroluminescent polymer in solution is used to improve the printability and performance of screen printed light-emitting polymer-based devices. Examples of such additives include transparent polymers, gel-retarders, high viscosity liquids, organic and inorganic salts, and oxide nanoparticles. The additives are used to control the viscosity of the electroluminescent polymer ink, to decrease the solvent evaporation rate, and to improve the ink consistency and working time. In addition, these additives can improve the charge injection and power efficiency of light emitting devices manufactured from the screen printable electroluminescent polymer ink.

1 . An electroluminescent device comprising an electroluminescent film, the electroluminescent film including a screen printed light-emitting polymer-based ink, wherein the light-emitting polymer-based ink includes: 
 a soluble electroluminescent organic material;    a first additive, the first additive being an organic solvent having a boiling point between about 120 and 200 degrees Celsius; and    a second additive, the second additive being a viscosity enhancer added to maintain a viscosity of above about 50 centipoises.