1. Bernal Institute, Department of Chemical Sciences, University of Limerick, Limerick V94 T9PX , Republic of Ireland.
2. Department of Chemistry, University of South Florida, 4202 East Fowler Avenue, CHE205, Tampa, FL 33620-5250, USA.
3. MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Physical and Chemical Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.