Ultrasonically spray coated PEIE as electron injection layer for OLEDs application

Abstract

Achieving trade-off between the high luminous efficacy and the cost-effective fabrication technique of an Organic light-emitting device (OLED) is quite challenging. Research lab fabrication facilities like the vacuum deposition, spin coating etc… and expensive materials offer best luminous efficacy of OLEDs, however, results in high costs of the devices built. Many industrial Roll to Roll (R2R) technologies like screen printing, dip coating, slot-die coating, inkjet printing offers etc… have been utilized to reduce the cost of OLEDs, But, the inability of the above-mentioned technologies to precisely control the thickness of the deposited layers hinders the usage of this technology in OLEDs fabrication. Ultra spray coating (USSC) technology combines the advantage of R2R and has precise control over the thickness of the deposited film, Polyethyleneimine ethoxylated (PEIE) could effectively replace Ca as an electron injection layer and reduces the production cost and hence USSC and PEIE are considered in our present study. As the minimum thickness achieved by the USSC is 15 nm, the present study focuses on the replication of the performance of an OLEDs obtained by spin coating at 15 nm thick PEIE as electron injection layer by USSC.