2019 MacDiarmid Medal: Using light to study molecules

Keith Gordon is a Professor of Chemistry at the University of Otago. He uses the interactions between light and matter—known as spectroscopy—to probe the molecular structures present in materials. His research has direct applications across the fields of technology, health and the environment, including the design of solar cells, the quality of pharmaceuticals and foodstuffs and the identification of microplastics in our environment.

His initial training was in the spectroscopy of excited states: these are transient species created when molecules absorb light and can last for microseconds. Keith has developed and adapted his initial training to use spectroscopy across a range of areas, using mathematical models to remove noise and obtain clear spectral signatures.

In solar cell research, Keith and his team have improved polymer solar cell performance. They used a combination of spectroscopy with computational chemistry to derive better dyes for dye-sensitised solar cells. These redesigned solar cells are better at absorbing light and better at conducting the charges created by light absorption. He has also worked to optimise plastic-based solar cells.

Keith then adapted the methods developed to understand solar cells to address analysis problems in pharmaceuticals. The issues with pharmaceuticals is not the purity of the compounds (which is often very high) but rather how the compounds are configured and interact in tableted form. Many drugs have a number of crystalline forms, called polymorphs, and these are used in formulations because they are stable. Identification of the different polymorphs has therapeutic and legal ramifications because polymorphs are patented separately. Keith, in collaboration with others, has developed more user-friendly methods to identify different pharmaceutical polymorphs. His methods can also be used to identify nano-crystallites, whereas conventional techniques, such as X-ray, fail due to the tiny scale of nano-crystals.

Keith has also contributed greatly to the assessment of foodstuff quality in foodstuffs, including dairy, fish and horticultural products. He has developed new methods to analyse the composition of materials and this has been used in a wide range of applications. These include the quality of fish oil (which taint due to oxidation); the composition of processed cheeses; the composition (fat, protein and carbohydrate content) of milk powder; and the determination of fructose, sucrose, glucose and other compounds in nectar.

On receiving this medal, Keith said: “I am very pleased to be awarded this prize. Science is a team effort and in addition to the students and postdocs I have worked with over the years, I would like to acknowledge the scholarly community that I enjoy working in at the University of Otago Chemistry Department, and my collaborators and colleagues in the Dodd-Walls Centre, the MacDiarmid Institute and the Riddet Institute. I would also like to thank my family, and particularly my partner Kathryn, for their support.”

Professor Gordon has more than 300 peer-reviewed publications, many of which are regarded as seminal. He was elected a Fellow of the New Zealand Institute of Chemistry (NZIC) in 2004, a Fellow of the Royal Society of Chemistry in 2011 and a Fellow of Royal Society Te Apārangi in 2012. In 2010 he was awarded the Maurice Wilkens Prize for excellence in Chemical Sciences by the New Zealand Institute of Chemistry.

MacDiarmid Medal:

For outstanding scientific research that demonstrates the potential for application for human benefit.

Citation:

To Keith Christopher Gordon for his innovative use of light to understand molecular structure across a range of areas that impinge on technology, health and the environment.