Abstract: The present invention relates to a nanocomposite comprising primary nanoparticles having a particle size of less than 10 nm said primary nanoparticles forming agglomerates with a bimodal size distribution, dispersed in a polymer matrix, wherein the nanocomposite comprises 10-80 wt. % of the agglomerates having a particle size of less than 30 nm and less than 20 wt. % of the agglomerates having a particle size of at least 100 nm, preferably at least 400 nm, based on the total weight of the agglomerates. The surface of the nanoparticles can be modified with a surface modifier. The composition can advantageously be used as an organic layer between two inorganic layers in high-refractive barrier structures for electronic devices such as organic light-emitting diode (OLED).