1. Instituto de Fisica “Gleb Wataghin”, Universidade Estadual de Campinas, UNICAMP, P.O. Box 6165, 13083-859 Campinas, Sao Paulo, Brazil
2. SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon-si, Gyeonggi-do 16419, South Korea
3. Display Research Center, Korea Electronics Technology Institute, Seongnam-si, Gyeonggi-do 13509, South Korea
4. Department of Chemical and Biomolecular Engineering, KAIST Institute for the Nanocentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea