1. Department of Chemistry and Institute of Basic Science, Chonnam National University, Gwangju 500-757, Republic of Korea
2. Department of Physics, Yeungnam University, Gyeongsan 38541, Republic of Korea
3. Institute of Energy Studies, University of North Dakota, Grand Forks, North Dakota, 58202, USA
4. Department of Materials Science and Engineering, Chonnam National University, Gwangju 61186, Republic of Korea
5. School of Architecture, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju, 61452, Republic of Korea