Materials and methods for controlling properties of organic light-emitting device

摘要

The present teachings provide methods for forming organic layers for an organic light-emitting device (OLED) using an inkjet printing or thermal printing process. The method can further use one or more additional processes, such as vacuum thermal evaporation (VTE), to create an OLED stack. OLED stack structures are also provided wherein at least one of the charge injection or charge transport layers is formed by an inkjet printing or thermal printing method at a high deposition rate. The structure of the organic layer can be amorphous, crystalline, porous, dense, smooth, rough, or a combination thereof, depending on deposition parameters and post-treatment conditions. An OLED microcavity is also provided and can be formed by one of more of the methods.

主权项

1. A method of forming an organic layer for an organic light-emitting device, the method comprising:
depositing an ink from an inkjet printhead onto a substrate, the ink being defined by a carrier and dissolved or suspended film-forming first organic material; and subjecting the deposited ink to a post-deposition heat-treatment comprising: driving off the carrier to deposit the film-forming first organic material and form a pre-bake organic layer comprising the first organic material on the substrate; and baking the pre-bake organic layer at a first bake temperature of from about 50° C. to about 250° C. for a first bake time of from about 5.0 milliseconds to about 5.0 hours to form a first baked organic layer comprising the first organic material for an organic light-emitting device; wherein one or more conditions of the ink deposition, the post-deposition heat treatment, or both, provide the first baked organic layer with at least one of a rough surface character, a porous structure, or a crystalline structure comprising one or more crystalline regions; and further wherein the surface roughness, the pores in the porous structure, or the one or more crystalline regions are formed during at least one of the ink deposition, the post-deposition heat treatment, or both; and further wherein at least one of the bake temperature, the bake time, the concentration of the film-forming first organic material in the ink, and the thickness of the pre-bake organic layer are adjusted such that the first baked organic layer has a surface roughness of from about 0.5 nm to about 1.0 μm expressed as the root mean square of the surface thickness deviation in an area 10×10 μm2.