Effects of embedded SiO₂ nanoparticles on the moisture barrier performance of inorganic/organic laminates

Thin-film encapsulation (TFE) is essential and challenging for flexible organic/quantum dot light-emitting diodes (OLEDs/QLEDs). In this work, SiO₂ nanoparticles were added into the NEA 121 polymer (s-NEA) to prolong the permeation pathways, showing good barrier property and high optical transparency. With increasing the concentration of SiO₂ nanoparticles up to 20 mg/ml, the value of water vapor transmission rate (WVTR) decreased. A single s-NEA layer with silica concentration of 20 mg/ml and thickness of ~ 75 µm exhibited WVTR of 2.5 × 10⁻³ g/m²/day and light transmittance of above 80%. Al₂O₃ thin films fabricated using atomic layer deposition were inserted between s-NEA layers to form dyad-style Al₂O₃/s-NEA multilayers. The Al₂O₃ (60 nm)/s-NEA (20 µm) multilayers with 3 units exhibited WVTR of 2.6 × 10⁻⁵ g/m²/day and consistently demonstrated a significantly extended QLED lifetime.