TEMPERATURE-DEPENDENT POLARIZATION IN LB FILMS OF A STILBAZOLE COMPLEX OF IRIDIUM(I)

The pyroelectric effect occurs in non-centrosymmetric, polar crystals and thin films whose spontaneous polarization changes as a function of temperature. In this paper, we report on a new organo-iridium complex which exhibits the pyroelectric effect. The alternate layer Langmuir- Blodgett deposition technique has been utilized to fabricate molecular assemblies which are polar at the macroscopic level. This technique f acilitates the co-deposition onto solid substrates of monolayer films of two different materials (A and B) floating at an air-water interfac e. These monolayers are deposited alternately such that the resulting layer structure is of the ABABA... form. This fabrication technology e nables polar molecules to be organized into thin multi-lammellae assem blies which possess a macroscopic polarization. The pyroelectric coeff icients of these films have been measured over a range of temperature. Several LB samples containing different numbers of iridium stilbazole monolayers have been examined showing that the optimum pyroelectric r esponse occurs for a film incorporating only 11 monolayers.