Oxygen and Moisture Barrier Coatings for Organic Electronics

Junghyun Cho and Hyungsuk Lee*
State University of New York (SUNY), Binghamton, New York 13902-6000

*Graduate student

Overview:

Organic electronics such as organic light emitting diode (OLED) received great attention both in consumer and military applications.  On rigid glass or Si substrates, isolation of the OLED from oxygen and moisture is typically accomplished with a glass or a metal lid, attached to the display substrate using a bead of UV-cured epoxy.  When organic substrates are employed in flexible display applications, a barrier layer is required on the substrate to protect the enclosed functional materials and layers from oxygen and water permeation.  One requirement is that the barrier coatings on the substrate not interfere with light transparency when emitted through this layer.

The proposed work follows the ‘biomimetic’ processing route by using the self-assembled monolayer (SAM) as a ‘template’ for the deposition of ceramic barrier coatings on a polymer substrate. The underlying SAM coating also acts as a buffer layer by providing compliance for the overlying hard ceramic coating upon mechanical and thermomechanical stresses [1].  This bilayer structure (ceramic-SAM) is overlaid on the polymer layer that ensures a conformal coverage over the organic substrate. In particular, ceramic is processed at very low temperature (< 100C) in aqueous solution, so the process is applicable to OLED structures, cheap and environment-friendly. 

Anticipated Results:

The proposed coatings would deliver enabling materials and processes for the conformal barrier coatings on the organic substrates for OLED layers that need protection from moisture and oxygen. The coatings are compatible with flexible substrates used in roll-to-roll manufacturing. They would not spall or be cracked for bending due to its strain tolerance resulting from the unique layered structure consisting of ceramic – buffer layer (SAM) – polymer, and its nano-particulate microstructure. 

Support for this project is provided by Center for Advanced Microelectronics Manufacturing / US Army.