Characteristics of transparent encapsulation materials for OLEDs prepared from mesoporous silica nanoparticle-polyurethane acrylate resin composites

Transparent encapsulation materials were fabricated by combining inorganic mesoporous silica nanoparticles (MSNPs) and a transparent polyurethane acrylate (PUA)-based resin. The surfaces of the synthesized MSNPs were successfully modified by a two-step sol-gel method with the coupling agent [3-(methacryloyloxy)propyl]trimethoxysilane (MPS). The bare and MPS-modified MSNPs possessed good hygroscopic properties (20% and 17%, respectively). The optimized MSNP-PUA composite containing 2 wt% MPS-modified MSNPs exhibited a high transparency (94.8%) with low haze (2.1%) and excellent encapsulation properties (lasted 576 h in a moisture permeability test at 85 °C and 85% RH).