1. a Institute of Nanoscience and Nanotechnology (ION2), Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia
2. b Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia
3. c Department of Physics, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia
4. d Center of Foundation Studies for Agricultural Science, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia