A flexible insulator of a hollow SiO2 sphere and polyimide hybrid for flexible OLEDsElectronic supplementary information (ESI) available. See DOI: 10.1039/c4cp04266b

The fabrication of interlayer dielectrics (ILDs) in flexible organic light-emitting diodes (OLEDs) not only requires flexible materials with a low dielectric constant, but also ones that possess the electrical, thermal, chemical, and mechanical properties required for optimal device performance. Porous polymer-silica hybrid materials were prepared to satisfy these requirements. Hollow SiO 2 spheres were synthesized using atomic layer deposition (ALD) and a thermal calcination process. The hybrid film, which consists of hollow SiO 2 spheres and polyimide, shows a low dielectric constant of 1.98 and excellent thermal stability up to 500 °C. After the bending test for 50 000 cycles, the porous hybrid film exhibits no degradation in its dielectric constant or leakage current. These results indicate that the hybrid film made up of hollow SiO 2 spheres and polyimide (PI) is useful as a flexible insulator with a low dielectric constant and high thermal stability for flexible OLEDs. A hollow SiO 2 sphere and polyimide hybrid with a low dielectric constant and high thermal stability is useful for flexible insulators.