1. Werkstoffe der Elektrotechnik and CENIDE, University of Duisburg-Essen 1 , Bismarckstr. 81, Duisburg 47057, Germany
2. School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University 2 , Seoul 08826, Republic of Korea
3. Center for Nanoparticle Research, Institute for Basic Science (IBS) 3 , Seoul 151-742, Republic of Korea