The plasma polymer of SiOxCy film has attracted much attention because it could possess both the organic and inorganic properties simultaneously for wide range applications. In this work, a SiOxCy film with a gradient composition through tuning the N2O/N2O + Ar ratio from 0% to 100% was used for TOLED encapsulation using hollow cathode discharge plasma. In order to confirm whether the plasma damage was caused during the PECVD process, a ZnO buffer layer prepared using RF sputtering was deposited before encapsulation. Furthermore, the reference samples with glass lid encapsulation were also used for comparison. The results showed that the SiOxCy film with a gradient composition cooperated with the sputtering ZnO buffer layer was a simple and effective method for TOLED encapsulation. (C) 2010 Elsevier B.V. All rights reserved.