INFLUENCE OF SUBSTITUENTS ON THE BEHAVIOUR OF POLYTHIOPHENE AS DONOR IN POLYMER-FULLERENE SOLAR CELLS

摘要

Polymer solar cells have evolved as a promising cost-effective alternative to silicon-based solar cells. However, low efficiency of these plastic solar cells limits their feasibility for commercial use. The efficiencies of polymer photovoltaic cells got a major boost with the introduction of the bulk heterojunction (BHJ) concept consisting of an interpenetrating network of electron donor and acceptor materials. In this work we describe the preparation of BHJ organic solar cells using blend films of poly[4,4'-bis(alkylsulfanyl)-2,2'-bithiophene] (P3ST) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 (PCBM). Photovoltaic cells were prepared with a layer sandwiched between electrodes with different work functions. The electrical performance of the devices were compared with the corresponding one prepared using a blend of commercial poly (3-hexylthiophene) (P3HT) and PCBM. The quantum efficiency of the device fabricated with P3ST/PCBM blend shows a better response in the visible region compared to the one with P3HT/PCBM.