A Low-Temperature Curable Conformal Adhesive Layer for Monolithic Lamination of Thin Film Encapsulation

Abstract

Lamination of a thin film encapsulation (TFE) layer is regarded as one of the most promising methods that enable the reliable operation of organic electronic devices by attaching the TFE layers thereon directly using an adhesive layer. In this study, a low-temperature curable adhesive thin film with low glass transition temperature (T g) is newly designed and synthesized. Low T g allows conformal contact at the interface of the adhesive layer and the substrate subsequently leads to the enhancement of adhesion, and thus the barrier performance of the lamination of barrier film increases. In order to fabricate a low-T g adhesive layer, glycidyl methacrylate (GMA) was copolymerized with a 2-hydroxyethyl acrylate (HEA) monomer in the vapor phase via initiated chemical vapor deposition. With a 5 µm thick p(GMA-co-HEA) adhesive layer, a strong adhesion was readily achieved by curing it at 60 °C for 1 h, with the peel strength of 16.6 N/25 mm, and the water vapor transmission rate of the glass-laminated encapsulation was as low as 3.4 × 10−3 g/m2 · day under accelerating conditions (38 °C, 90% relative humidity). We believe the low-temperature curable thin adhesive layer will serve as a powerful material for the lamination of organic electronic devices in a damage-free way.