Research Themes
Theme 3
Theme 3: Molecular Materials
The Institute's research in Molecular Materials School of Chemical & Physical Sciences, Victoria University of Wellington, the Institute of Fundamental Sciences - Chemistry, Massey University, and the Chemistry Department, Otago University.
Theme Leader: Professor Keith Gordon
Molecular materials find diverse applications and researchers in this theme have expertise in many of these, including: molecular magnets, solar energy and electroluminescent materials, functional surfaces and supramolecular assemblies. Our challenge now is to further develop molecules and use our knowledge in the construction of larger (>100 nm) assemblies whether on a surface or as a three-dimensional structure. These larger ordered systems are critical to success in a number of applications including solar cells, organic light emitting diodes (OLEDs), sensors and magnets.
- Functional materials: We have made a strong contribution to the design and synthesis of new compounds including functionalized porphyrins, and thiophene oligomers, self-assembly and templating methods to create single molecule magnets, and coordination chemistry to improve charge flow in electronic materials such as OLEDs. In making further progress design challenges need to be met. For example, in solar cells and OLED systems photodegradation is a major problem; we will investigate this by sheathing light active units within cyclodextrins or cucurbiturals to protect the photoactive unit. In single molecule magnets we will undertake a systematic study of structure-magnetic behaviour as a function of changes to the ligand employed; cavity specific macrocycle encapsulation of magnetic metal ions is possible along with tunable electronic and solubility characteristics thus providing a ‘designed/controlled’ approach to generating such materials.
- Functional surfaces: The success of devices fabricated from molecular materials lies in an understanding of electrode surfaces and control of substrate positioning. We have considerable experience in these areas and will study of the electrochemicallycontrolled nucleation and growth of conducting phases. This work will build on previous studies and will address nucleation kinetics and transition from 2- dimensional to 3-dimensional growth. We will investigate the covalent attachment of organic layers to conducting substrates. Radical grafting methods generate a Csurface bond which is very stable attachment of the organic layer. We have shown detailed insight into nanometre-thick organic layers grafted to conducting carbon surfaces. We will expand these studies, focussing on the reactivity of the layers (for example giving switchable wettability).
- Supramolecular Arrays: The conduction of charges in a spatially controlled fashion is a desirable property in electroactive materials. We will form conducting wires that are microns long and nanometres in diameter (3 – 4 nm) by using discotic liquid crystal forming materials that will self-organise within polymer nanotubes. Nanoparticle systems are fascinating from the viewpoints of both fundamental research and applied nanotechnology. Despite intense research efforts of late, methods for assembling nanoparticles into specific 1-, 2- and 3-dimensional arrangements remain rather crude. Research in this area is crucial as spatially well-defined nanoparticle arrays are essential for future applications in molecular electronic devices and chemoand biosensors. We will create a toolbox of coordination chemistry to organize nanoparticles into pre-designed arrays.
- Capability: Our work continues to be published in premier journals – being highlighted in a number of cover articles. We have several patents, and the work related to functional surfaces assisted in the formation of the spin-off company Anzode.
- New magnetic molecules based around novel complexes. This year we will prepare and characterise some key dinuclear spin crossover systems based on cobalt and iron complexes which can undergo simultaneous magnetic exchange and spin crossover, these will be strucuturally characterised by X-ray crystallography and Mössbauer spectroscopy. (S. Brooker)
- Nanoscale organic layers: structure, properties and patterning. This year we will focuseon preparing chemically well-defined surfaces on carbon substrates by assembling molecular species on the surface. Electrochemical methods are used to covalently graft modifiers to the surface and we are investigating further functionalization and patterning of these layers using chemical and physical techniques. Controlled physicochemical modification of carbon surfaces leads to applications such as sensor design, biochip fabrication and novel large surface area support materials. (A.J. Downard)
- Supramolecular assemblies for use in electroluminescent displays and solar cells. Current conducting polymer technology is cheap and easy to process but they are disadvantaged in that they possess a disordered polymer structure, decreasing effi ciency. This year we will develop a series of complexes that will overcome this problem by self-assembling into liquid crystal columns. The carefully designed structure of the complexes will allow formation into the liquid crystal columns. This self-assembly will facilitate the transport of charge through the liquid crystal columns, in effect acting as molecular wires. (K.C. Gordon)
- Nucleation and growth of electroactive materials. This year we will use electrochemical techniques as a means of controlling and/or determining the rate of redox processes. (S.B. Hall)
- Development of carbon nanotube facility at Massey University. This year we will focus on the development of carbon nanotubes for use in a series of applications that span animal health through to photovoltaics. (A. Partridge)
- Metal-Driven Assembly of Functional Nanomaterials. This year we will focus on the development of dipyrrin based ligands for use in assembly construction. The electronic and synthetic properties of these materials will be investigated. (S.G. Telfer)
- Micro- and nanopatterned structures of conducting polymers. This year we will focus on developing patterned structures utilizing polypyrrole as a base material. (J. Travas-Sejdic)
