It is well known that organic solar cells (OSCs) are made using organic materials because of their mechanical flexibility and low manufacturing cost. Their efficiency, however, remains low for several reasons, including limited light absorption and poor charge mobility. Although OSCs are a fascinating supplement to silicon-based solar cells, they have yet to provide good efficiency for a prolonged period. Combining a narrowband donor and an electron acceptor [regioregular poly 3-hexylthiohene-2,5-diyl (rr-P3HT) and 6,6-phenyl-C61-butyric acid methyl ester (PC61BM), respectively] is a prevalent approach towards efficient organic cells. In our work, a device of configuration indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS)/rr-P3HT:PC61BM/Al was fabricated and characterized both electrically and optically. Various solar cell constraints were optimized to maximize the performance of OSCs. Ultimately, a device with a maximum power conversion efficiency (PCE) of approximately 1.4% was achieved under the optimum fabrication conditions.