Close-Spaced Sublimation of Organic Materials for Organic Light-Emitting Devices

Abstract

We have demonstrated organic light-emitting devices (OLEDs) fabricated by using a close-spaced sublimation (CSS) method. We have deposited tris(8-hydroxyquinolinato)aluminum (Alq 3 ) layer using a CSS process for the formation of electron transport layer of the PVK/Alq 3 bilayer OLEDs. The distance between the sublimation source and substrate was fixed to be less than 5 mm. The substrate temperature was maintained less than 70 • C while the sublimation source temperature was varied from 185 to 200 • C during the deposition of Alq 3 film. We investigated the photoluminescence characteristic of the CSS processed Alq 3 film. We also investigated the emission and electro-optical properties of the PVK/Alq 3 bilayer OLEDs with CSS deposited Alq 3 film.