Advances in Photoconductive and Photorefractive Cyclometalated Complexes Development

We present results on the photorefractive performance of cyclometalated complexes in which a central metal atom (Pd or Pt) coordinates two different molecular sub-units in a single species. Depending on the details of their structure, these molecules aggregate in crystals, glasses or liquid crystalline phases. The photorefractive properties of the complexes are discussed by treating separately results obtained in different phases. Crystalline compounds can be dissolved in suitable polymers and we show how phase separation in polymeric composites, which is usually detrimental for sample stability, can be controlled and used to increase photorefractive performance parameters by orders of magnitude. In addition, we present a method for estimating the intensity of the space-charge field in chiral smectic phases without using any of the standard models developed for crystalline or amorphous materials.