1. Department of Chemistry, Faculty of Science, Chiang Mai University, 239 Houy Kaew Road, Chiang Mai 50200, Thailand
2. Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
3. Department of Chemistry, Graduate School of Science, Osaka University, Osaka 560-0043, Japan
4. Department of Physic and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 Thailand