3 years ago

Thiophene Rings Improve the Device Performance of Conjugated Polymers in Polymer Solar Cells with Thick Active Layers

Thiophene Rings Improve the Device Performance of Conjugated Polymers in Polymer Solar Cells with Thick Active Layers
Feng Liu, Stefan C. J. Meskers, René A. J. Janssen, Ke Gao, Fallon J. M. Colberts, Martijn M. Wienk, Chunhui Duan
Developing novel materials that tolerate thickness variations of the active layer is critical to further enhance the efficiency of polymer solar cells and enable large-scale manufacturing. Presently, only a few polymers afford high efficiencies at active layer thickness exceeding 200 nm and molecular design guidelines for developing successful materials are lacking. It is thus highly desirable to identify structural factors that determine the performance of semiconducting conjugated polymers in thick-film polymer solar cells. Here, it is demonstrated that thiophene rings, introduced in the backbone of alternating donor–acceptor type conjugated polymers, enhance the fill factor and overall efficiency for thick (>200 nm) solar cells. For a series of fluorinated semiconducting polymers derived from electron-rich benzo[1,2-b:4,5-b′]dithiophene units and electron-deficient 5,6-difluorobenzo[2,1,3]thiazole units a steady increase of the fill factor and power conversion efficiency is found when introducing thiophene rings between the donor and acceptor units. The increased performance is a synergistic result of an enhanced hole mobility and a suppressed bimolecular charge recombination, which is attributed to more favorable polymer chain packing and finer phase separation. Introducing additional thiophene rings in conjugated polymers increases the fill factor and power conversion efficiency of polymer:fullerene solar cells with thick active layers. This “thiophene ring effect” is a synergistic result of enhanced hole mobility and suppressed bimolecular charge recombination via the formation of more favorable polymer chain packing and finer phase separation.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/aenm.201700519

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.