1. Department of Physics, College of Science, Engineering and Technology University of South Africa Johannesburg 1710 South Africa
2. Department of Pure and Applied Physics Ladoke Akintola University of Technology Ogbomoso Nigeria
3. Institute for the Development of Energy for African Sustainability, College of Science, Engineering and Technology University of South Africa Johannesburg South Africa
4. Department of Chemistry and Industrial Chemistry Kwara State University Malete Ilorin Nigeria