1. MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Physics, University of Auckland, Private Bag 92019, Auckland, New Zealand
2. MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Physics, School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand
3. MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand