1. Department of Chemistry, Faculty of Mathematic and Natural Sciences, University of Lampung, Jl. Soemantri Brodjonegoro No. 1 Bandar Lampung, 35145, Indonesia.
2. Department of Electrical Engineering, Faculty of Engineering, University of Lampung, Jl. Soemantri Brodjonegoro No. 1 Bandar Lampung, Indonesia.