1. Laboratoire de Physique Appliquée, Groupe de Physique des Matériaux Luminescents, Faculté des Sciences, Université de Sfax, BP 1171, 3000 Sfax, Tunisia
2. Imam Mohammad Ibn Saud Islamic University (IMSIU), College of Sciences, Department of Physics, Riyadh 11623, Saudi Arabia
3. Laboratory of Physics of Materials and Nanomaterials Applied at Environment (LaPhyMNE), Faculty of Sciences in Gabes, Gabes University, 6072 Gabes, Tunisia
4. University of Coimbra, CFisUC, Physics Department, P-3004-516 Coimbra, Portugal