Light-induced reorientation and birefringence in polymeric dispersions of nano-sized crystals

Nanocrystals (50-250 nm) of a Palladium complex within a polyisobutylmethacrylate matrix were prepared by a phase separation method. In these dispersions, a light-induced birefringence with ”n < 10-3 was induced, without the application of an electric field. This effect was related to the photoconducting properties of the dispersion. Evidence for charge photogeneration without any applied field was obtained. The photorefractive behaviour of the material confirmed that the nanocrystals reorientation is a consequence of photoconducting properties. A lightgenerated electric field E < 3 V/¼m was estimated. These results illustrate the potential of materials with a nano-crystalline dispersion morphology as light-responsive media.