Photocathodes beyond NiO: charge transfer dynamics in a π-conjugated polymer functionalized with Ru photosensitizers
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Wahyuono, Ruri A.; Seidler, Bianca; Bold, Sebastian; Dellith, Andrea; Dellith, Jan; Ahner, Johannes; Wintergerst, Pascal; Lowe, Grace; Hager, Martin D.; Wächtler, Maria; Streb, Carsten; Schubert, Ulrich S.; Rau, Sven; Dietzek, Benjamin
- Abstract:
- A conductive polymer (poly(p-phenylenevinylene), PPV) was covalently modified with RuII complexes to develop an all-polymer photocathode as a conceptual alternative to dye-sensitized NiO, which is the current state-of-the-art photocathode in solar fuels research. Photocathodes require efficient light-induced charge-transfer processes and we investigated these processes within our photocathodes using spectroscopic and spectro-electrochemical techniques. Ultrafast hole-injection dynamics in the polymer were investigated by transient absorption spectroscopy and charge transfer at the electrode–electrolyte interface was examined with chopped-light chronoamperometry. Light-induced hole injection from the photosensitizers into the PPV backbone was observed within 10 ps and the resulting charge-separated state (CSS) recombined within ~ 5 ns. This is comparable to CSS lifetimes of conventional NiO-photocathodes. Chopped-light chronoamperometry indicates enhanced charge-transfer at the electrode–electrolyte interface upon sensitization of the PPV with the RuII complexes and p-type behavior of the photocathode. The results presented here show that the polymer backbone behaves like classical molecularly sensitized NiO photocathodes and operates as a hole accepting semiconductor. This in turn demonstrates the feasibility of all-polymer photocathodes for application in solar energy conversion.
- Year:
- 2021
- Type of Publication:
- Article
- Journal:
- Scientific Reports
- Volume:
- 11
- Pages:
- 2787
- DOI:
- https://doi.org/10.1038/s41598-021-82395-x