Institute of Physics, University of Freiburg, Hermann-Herder-Strasse 3, 79104 Freiburg, Germany Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, U.K. Department of ...

These natural wonders are examples of structural colors -- a phenomenon in which microscopic ... a negatively charged chemical group adds to an α, β-unsaturated carbonyl compound for introducing ...