1. Nano-Material Research Laboratory, Department of Chemistry, Indian Institute of Technology (BHU), Varanasi, Uttar Pradesh 221005, India
2. Department of Applied Sciences, Faculty of Engineering & Technology, Rama University, Kanpur, Uttar Pradesh 209217, India
3. Department of Physics, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh 221005, India