Designing Simple Conjugated Polymers for Scalable and Efficient Organic Solar Cells

Conjugated polymers have a long history of exploration and use in organic solar cells, and over the last twenty‐five years, marked increases in the solar cell efficiency have been achieved. However, the synthetic complexity of these materials has also drastically increased, which makes the scalability of the highest‐efficiency materials difficult. If conjugated polymers could be designed to exhibit both high efficiency and straightforward synthesis, the road to commercial reality would be more achievable. For that reason, a new synthetic approach was designed towards PTQ10 (=poly[(thiophene)‐alt‐(6,7‐difluoro‐2‐(2‐hexyldecyloxy)quinoxaline)]). The new synthetic approach to make PTQ10 brought a significant reduction in cost (1/7th the original) and could also easily accommodate different side chains to move towards green processing solvents. Furthermore, high‐efficiency organic solar cells were demonstrated with a PTQ10:Y6 blend exhibiting approximately 15 % efficiency. A new path: The synthesis of the PTQ10 conjugated polymer is redesigned to realize a low‐cost organic solar cell material. While the original synthetic route enjoyed low synthetic complexity and high efficiency, the overall polymer cost was too high. Along with lowering the cost, this new approach can easily accommodate further functionalization. Organic solar cell performance is successfully reproduced through this route at 1/7th the polymer cost of the original route.