Sol-gel derived transparent zirconium-phenyl siloxane hybrid for robust high refractive index LED encapsulant.

We report a zirconium-phenyl siloxane hybrid material (ZPH) that can be used as a robust LED encapsulant. The ZPH encapsulant was fabricated via hydrosilylation-curing of sol-gel derived multifunctional (vinyl- and hydride-functions) siloxane resins containing phenyl-groups and Zr-O-Si heterometallic phase for achieving a high refractive index (n ≈ 1.58). In thermal aging, the ZPH LED encapsulant exhibited superior performances with a high optical transparency (∼88% at 450 nm) and exhibited high thermal stability (no yellowing at 180 °C for 1008 h), compared to a commercial LED encapsulant (OE-6630, Dow Corning Corporation). This suggests potential for ZPH to be a robust LED encapsulant.