1. Department of Chemistry, University of Kerala, Kariavattom Campus, Thiruvananthapuram, Kerala 695 581, India
2. Post Graduate and Research Department of Chemistry, Sree Narayana College, University of Kerala, Kollam, Kerala 691 001, India
3. Centre for Renewable Energy and Materials, University of Kerala, Kariavattom Campus, Thiruvananthapuram, Kerala 695 581, India