Following a major forgery of Australias newly introduced $10 notes in 1967, Solomon was invited to a meeting about how to make more secure bank notes. Given his background in polymer science Solomons idea was to print the notes on a plastic substrate rather than the traditional paper, and incorporate optically variable devices – defined as a device that changes its appearance when something external is done to the note.
Solomon went on to lead the research team and was the principal inventor of the worlds first polymer banknote, with the first note issued into circulation in 1988: the Australian bicentennial $10. He has chronicled the history of the development of polymer banknotes in The Plastic Banknote: From Concept to Reality', co-authored with Tom Spurling (published in 2014).