1. Institute of Microtechnology (IMT), University of Neuchâtel, Rue Jaquet-Droz 1, CH-2007 Neuchâtel, Switzerland, Centre Suisse d'Electronique et de Microtechnique SA (CSEM), Rue Jaquet-Droz 1, CH-2007 Neuchâtel, Switzerland, and Swiss Federal Institute of Technology (ETH), Laboratorium für Organische Chemie, Universitätstrasse 16, CH-8092 Zürich, Switzerland