1. Department of Organic and Nano System Engineering, Konkuk University, Seoul 143-701, Korea
2. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
3. Department of Organic Materials and Fiber
Engineering, Soongsil University, Seoul 156-743, Korea
4. Department of Physics, Soongsil University, Seoul 156-743, Korea
5. Department
of Materials Science and Engineering, Jungwon University, Goesan 367-805, Korea
6. SKKU Advanced Institute
of Nanotechnology (SAINT) and School of Chemical Engineering, Sungkyunkwan University, Suwon 440-746, Korea