Abstract: An optical device having a layer comprising an organic material that includes a substantially uniform dispersion of light transmissive nanoparticles.

Abstract: A display device comprising a primary light-emissive region, a light-sensitive region and a secondary light-emissive region, wherein: the primary light-emissive region comprises an organic light-emissive material and a pair of electrodes arranged to apply an electric field across the light-emissive material to cause it to emit light; the light-sensitive region comprises a photocathode responsive to light from the primary light-emissive region to release charged particles towards the secondary light-emissive region; sand the secondary light-emissive region comprises a phosphorescent material excitable by the charged particles from the light-sensitive region to emit light.