1. Centre for Ionics University of Malaya, Department of Physics, Faculty of Science, Universiti Malaya, Kuala Lumpur 50603, Malaysia
2. King Abdullah Institute for Nanotechnology, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
3. Institute of Nano and Advanced Materials Engineering, Sejong University, Seoul 05006, Republic of Korea
4. Graphene Research Institute, Sejong University, Seoul 05006, Republic of Korea
5. Department of Physics, Swami Shraddhanand College, University of Delhi, Delhi 110036, India
6. Higher Institution Centre of Excellence (HICoE), UM Power Energy Dedicated Advanced Centre (UMPEDAC), Level 4, Wisma R&D, Universiti Malaya, Jalan Pantai Baharu, Kuala Lumpur 59990, Malaysia
7. Department of Chemistry, Saveetha School of Engineering, Institute of Medical and Technical Science, Saveetha University, Chennai 602105, Tamilnadu, India