1. Department of Physics; Indian Institute of Technology Patna; Patna 801103 India
2. Department of Chemistry; Indian Institute of Technology Patna; Patna 801103 India
3. Raman Research Institute, Sadashivanagar; Bengaluru 560 080 India
4. Centre for Nano and Soft Matter Sciences; Prof. U. R. Rao Road, Jalahalli Bengaluru 560013 India