1. Department of Chemical Sciences, Tezpur University, Assam, India, 784028
2. Department of Electronics and Communication Engineering, Tezpur University, Assam, India, 784028
3. Department of Chemistry, Cotton University, Assam, India, 781001
4. Centre for Advanced Materials and Industrial Chemistry (CAMIC), School of Sciences, RMIT University, G.P.O. Box 2476, Melbourne 3001, Australia