The melanins are a class of functional bio-macromolecule found throughout nature. In humans they serve as our primary photoprotectants and pigment. As a biomolecule class they possess a number of intriguing physico-chemical properties including: broad band monotonic absorbance in the UV and visible; condensed phase electrical and photoconductivity; extremely efficient non-radiative relaxation of photoexcited electronic states (melanins have radiative quantum yields <1%); and free radical scavenging and anti-oxidant behaviour.

In the materials found in your laptop or mobile phone the interactions between the electrons are relatively small; this greatly simplifies the task of describing their behaviour. Technically, one says that the electrons in these materials are ‘weakly correlated’. Over the past few decades many new materials have been found which cannot be described within the weakly correlated paradigm. These materials, which are referred to as ‘strongly correlated’ and include cuprates [Lee], manganites [Milward] and organic charge transfer salts [Powell, Seo], have a wide variety of potential applications including catalysis [Shelef], energy applications [Fleming], and display technologies [Lo]. However, our lack of fundamental understanding of strongly correlated materials greatly hampers materials development for such applications.