1. P. E. S's. Ravi S. Naik College of Arts and Science, Farmagudi, Ponda, Goa, India
2. Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, Kolhapur-416004, Maharashtra, India
3. School of Chemical Sciences, Goa University, Taleigao Plateau, Goa 403206, India