1. Universiti Putra Malaysia; Institute of Advanced Technology; 43400 Serdang, Selangor Malaysia
2. University of Malaya Photonics Research Centre; 50603 Kuala Lumpur Malaysia
3. King Saud University; College of Science; Chemistry Department; P.O. Box 2455 11451 Riyadh Saudi Arabia
4. Tunis El Manar University; Science College; Chemistry Department; UR Physico-Chimie des Matériaux Solides; 2092 Tunis Tunisia