ABSTRACT
A typical OLED device consists of several thin layers deposited on top of each other (see Section I of this book for detailed discussions of various aspects of OLED structures). Starting from the anode, these typically include the hole-injection layer (HIL), holetransport layer (HTL), emissive layer (EML), and electron-transport layer (ETL). Some device architectures incorporate one or several blocking layers, but their utilization is typically limited to vapor-deposited devices. All four organic layers can potentially be deposited out of solution. e thickness of individual layers is typically between 5 and 100 nm. Patterning is used to ensure that at least one layer is no wider than the resolution of the overall display. ickness uniformity is critical, since changes in layer thickness result in poor color, high voltage, and lower device lifetime.
