1. Department
of Energy and Materials Engineering and Advanced Energy and Electronic
Materials Research Center, Dongguk University-Seoul, Seoul 100-715, Republic of Korea
2. Graduate
School of Energy, Environment, Water, and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro,
Yuseong-gu, Daejeon 305-701, Republic of Korea