Polymer Solar Cells: Recent Approaches and Achievements

Polymersolar cells have gained wide interest in the past few years for their potential in the field of large-area and low-cost photovoltaic devices. Thanks to rather simple treatments developed in the new millennium, the morphology of polymer solar cells has been optimized at the nanoscale level, leading to high efficient charge-carrier photogeneration and collection. Power conversion efficiency up to 6% and 6.5% have been reported in the literature for solution-processed polymer solar cells in single-junction and tandem configuration, respectively, and a record efficiency of 6.77% has been recently announced. After an introduction into the operational principles and device structure of polymer solar cells, this paper provides an overview of the last-years research activity. In particular, the different treatments successfully performed on polymer active layers, and their beneficial effects on the overall device efficiency are discussed. Subsequently, some significant examples of photoactive materials will be examined, outlining the foremost structure−properties relationships. Some directions for further enhancement of the performance of polymer solar cells will be also introduced, mainly through the fine-tuning of the electronic properties of the active materials.