1. Organic Semiconductor Centre; EaStCHEM School of Chemistry; University of St Andrews; St Andrews, Fife KY16 9ST UK
2. CEISAM UMR CNRS 6230; Université de Nantes; 2 rue de la Houssinière, BP 92208 44322 Nantes Cedex 3 France
3. Institut Universitaire de France; 1, rue Descartes 75005 Paris Cedex 5 France
4. School of chemistry; University of Leeds; Woodhouse Lane Leeds LS2 9JT UK