1. Chemical Sciences and Technology Division CSIR-National Institute for Interdisciplinary Science and Technology Thiruvananthapuram 695019 Kerala India
2. Inter University Centre for Nanomaterials and Devices (IUCND) Cochin University of Science and Technology Kochi Kerala 682022 India
3. Current address: Madanapalle Institute of Technology & Science (MITS) Madanapalle, Chittoor Andhra Pradesh 517325 India
4. Department of Applied Chemistry Cochin University of Science and Technology Kochi Kerala 682022 India