5 years ago

Harnessing Molecular Photon Upconversion in a Solar Cell at Sub-solar Irradiance: Role of the Redox Mediator

Harnessing Molecular Photon Upconversion in a Solar Cell at Sub-solar Irradiance: Role of the Redox Mediator
Kenneth Hanson, Sean P. Hill
Self-assembled bilayers offer a promising strategy to directly harness photon upconversion via triplet–triplet annihilation (TTA-UC) and increase maximum theoretical solar cell efficiencies from 33% to >43%. Here we demonstrate that the choice of redox mediator in these solar cells has a profound influence on both the light harvesting and TTA-UC efficiency. Devices with CoII/III(phen)3 as the redox mediator produced the highest photocurrent yet generated from TTA-UC (0.158 mA cm–2) under 1 sun. Despite generating less photocurrent, CoII/III(pz-py-pz)2 devices achieved maximum TTA-UC efficiency at excitation intensities well below solar irradiance (0.8 mW cm–2), which is on par with the lowest value yet reported for any TTA-UC system. The large variation in performance with respect to mediator is attributed to triplet excited-state quenching via (1) energy transfer or paramagnetic quenching by the CoII species and (2) excited-state electron transfer to CoIII species.

Publisher URL: http://dx.doi.org/10.1021/jacs.7b05462

DOI: 10.1021/jacs.7b05462

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.