Electroluminescent colloidal inks for flexographic roll-to-roll printing

The academic and commercial interest in organic light-emitting devices is motivated in part by the potential of building devices utilizing simple and inexpensive fabrication routes, for example, commercial printing techniques. The focus on synthetically challenging small molecules and π-conjugated polymers for these devices is countered by the alternative of developing emissive materials that utilize an electroluminescent dye embedded in a hole and electron transporting host. In this effort, we exploit readily obtainable materials and simple fabrication routes to produce light-emitting colloidal particles, which in turn allows us to invoke the concept of a "particle device". Specifically, we present colloidally based organic light emitting devices that can be designed to produce a range of colors by mixing together various ratios of red-, green-, and blue-emitting particles. These aqueous-based colloids are adaptable to form printing inks and may be utilized in fabricating devices through high-throughput commercial printing technologies.