Study on effect of substituents grafted on cyclopenta-fused anthracences as the cascade material for improving ternary bulk heterojunction photovoltaic cells

Abstract

Searching alternatives to enhance the attainable conversion efficiency of organic photovoltaics is one of the most crucial issues toward renewable energy source. Here, the model ternary organic solar cells systems were designed to improve the performance of P3HT/PC61BM organic solar cells which promise a potential to large area and flexible fabrication, based on a group of cyclopent[hi]aceanthrylenes (CPAs) derivatives as the third cascade component in active layer of the device. In all of these solar cells, although all ternary structures containing a group of cyclopent[hi]aceanthrylene derivatives demonstrate the improvement of open-circuit voltage (VOC) compared to binary device of P3HT/PC61BM, the conversion efficiencies of these devices can not all be improved. This indicates the different influence on observable device metrics attributed by the different substituents around cyclopent[hi]aceanthrylene core. By extension, these results suggest that the ternary system used a simple one single active layer processing step can provide a potentially effective way to optimize the performance in BHJ solar cells.