Low dielectric loss and high breakdown strength photosensitive high-k composites containing perfluoroalkylsilane treated BaTiO₃ nanoparticles

High-k, UV curable polymer composites with low dielectric loss and high breakdown strength were prepared. Fluorosilane coupling agent (FAS-17) was adopted to modify the surface of BaTiO₃ (BT) nanoparticles. Characterization results of UV-cured composites filled with BT@FAS-17 particles indicate that the dielectric loss is dramatically decreased and the breakdown strength is significantly improved, especially for the highly-loaded composites. The underlying mechanism of these performance improvements is further studied by temperature-dependent dielectric spectra, thermally stimulated depolarization current experiments as well as the first-principle simulation, which suggest that H-bonding and additional interfacial traps introduced by FAS-17 account for the enhanced dielectric properties. This work proposes a facile and efficient technique for the fabrication of photosensitive high-k composites with low dielectric loss and high breakdown strength, which is suitable for a variety of advanced applications such as energy storage, functionally graded dielectric materials and 3D-printing fabrication of dielectrics.