Facilitation of transparent gas barrier using SiNx/a-IZO lamination for organic light emitting diodes

• We report an ultrathin SiNx/a-IZO laminated structure for thin film encapsulation.
• The laminated structure was fabricated by industrial-scale PECVD/PVD system.
• The amorphous a-IZO can cutoff the continuous growth of defect in SiNx film.
• The SiNx/a-IZO barrier exhibits a lower WVTR value as 5.21 × 10−4 g/m2/day.
• The encapsulated OLED devices show a longer lifetime that exceeds 600 hours.

We investigate a full inorganic transparent barrier that alternately consist of a layer of SiNx using plasma-enhanced chemical vapor deposition and a layer of amorphous indium-zinc-oxide (a-IZO) using plasma vapor deposition. Full inorganic thin film barriers showed a lower water vapor transmission rate (WVTR) of 5.21 × 10−4 g/m2/day with three dyads of SiNx/a-IZO stacking evaluated by Calcium (Ca) corrosion test. In consequence, the organic light-emitting diodes (OLEDs) encapsulated with laminated SiNx/a-IZO barriers show longer continuous operation lifetime under environmental and driving conditions. This means that the fully inorganic encapsulated structure were quite suitable for the obstruction of water and oxygen gas permeation and their integrated OLEDs luminance decay time were improved by a considerable extent. These were attributed to the modification of barrier performance by the introduction of a-IZO film which has functions of structure decoupling, tortuous paths formation, and water or oxygen getter.

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