1. Addis Ababa University, College of Natural Sciences, Materials Science Program, P. O. Box 1176, Addis Ababa, Ethiopia
2. Addis Ababa University, College of Natural Sciences, Department of Chemistry, P. O. Box 1176, Addis Ababa, Ethiopia
3. Chinese Academy of Sciences, Institute of Chemistry, CAS Key Laboratory of Organic Solids, Beijing 100080, China
4. Addis Ababa University, College of Natural Sciences, Materials Science Program, P. O. Box 1176, Addis Ababa, EthiopiabAddis Ababa University, College of Natural Sciences, Department of Chemistry, P. O. Box 1176, Addis Ababa, Ethiopia