2 research outputs found
The preparation and characterisation of novel organo-ruthenium Langmuir-Blodgett films
In recent years, there has been considerable interest in media which exhibit
significant non-linear physical properties. The non-linear optical response of many
materials has attracted a great deal of attention from the telecommunications industry
owing to their possible use for signal processing applications. Also, applications such as
thermal imaging depend ultimately upon the proficient operation of the active material
within the device structure. Traditionally, inorganic materials such as lithium niobate and
strontium barium niobate have been used for non-linear optics and infra-red detection.
However, the last decade or so has exposed the potentially high efficiency offered by
organic materials which, coupled to the ability to engineer their physical properties by
subtle modifications at the molecular level, suggests an exciting and productive future.
In order to maintain compatibility with existing integrated optics and display
technologies, it is often useful to process the active compound in thin film form. The
stringent symmetry requirements imposed upon the molecules and their organisation in the
macroscopic structure necessitates the existence of non-centrosymmetric molecular
structures for second-order non-linear applications such as those mentioned above. The
Langmuirandndash;Blodgett deposition technique enables such assemblies to be constructed by the
sequential transfer of organic monomolecular layers from a liquid-air interface onto a solid
substrate. The precise control of film thickness and molecular architecture afforded by the
technique allow polar multilayer structures to be produced which possess the properties
required for highly efficient second-order non-linear physical operation.
This thesis describes the development of a series of novel organo-metallic
complexes which possess the necessary molecular properties for LB deposition in addition
to those required for the observation of a large non-linear response. The complexes offer
substantially improved thermal stability over other LB materials, and are thus appealing to
the industrial device engineer. Their physical properties have been systematically studied
and related to their detailed molecular structure. In particular, optical second-harmonic
generation studies have shown that they possess high molecular coefficients and have
provided a launching stage for further development. Their high pyroelectric response has
attracted much enthusiasm from both industry and academia because of their potential
commercial exploitation in thermal imaging devices.</p