**2.4 Sample preparation for luminescence studies**

Rareearth ions europium and samarium of weight ratio of 0.28% were dissolved. Various concentrations of silver nanoparticles (0.16, 0.33, 1, 1.6, 2.32, 3.32 and 6.64 μM) were added to 0.10, 0.13, 0.20 μM of europium and 1.32, 1.45, 1.58 μM of samarium for luminescence studies.
