Structure–activity relationships in well-defined conjugated oligomer photocatalysts for hydrogen production from water

Catherine M. Aitchison, Michael Sachs, Marc A. Little, Liam Wilbraham, Nick J. Brownbill, Christopher M. Kane, Frédéric Blanc, Martijn A. Zwijnenburg, James R. Durrant, Reiner Sebastian Sprick, Andrew I. Cooper

Research output: Contribution to journalArticle

Abstract

Most organic semiconductor photocatalysts for solar fuels production are linear polymers or polymeric networks with a broad distribution of molecular weights. Here, we study a series of molecular dibenzo[b,d]thiophene sulfone and fluorene oligomers as well-defined model systems to probe the relationship between photocatalytic activity and structural features such as chain length and planarity. The hydrogen evolution rate was found to vary significantly with bridge head atom, chain length, and backbone twisting. A trimer (S3) of only three repeat units has excellent activity for proton reduction with an EQE of 8.8% at 420 nm, approaching the activity of its polymer analogue and demonstrating that high molar masses are not a prerequisite for good activity. The dynamics of long-lived electrons generated under illumination in the S3 oligomer are very similar to the corresponding polymer, both under transient and quasi-continuous irradiation conditions.
Original languageEnglish
Pages (from-to)8744-8756
Number of pages13
JournalChemical Science
Volume11
Issue number33
DOIs
Publication statusPublished - 7 Sep 2020

Keywords

  • organic semiconductor photocatalysts
  • solar fuel
  • linear polymers

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    Aitchison, C. M., Sachs, M., Little, M. A., Wilbraham, L., Brownbill, N. J., Kane, C. M., Blanc, F., Zwijnenburg, M. A., Durrant, J. R., Sprick, R. S., & Cooper, A. I. (2020). Structure–activity relationships in well-defined conjugated oligomer photocatalysts for hydrogen production from water. Chemical Science, 11(33), 8744-8756. https://doi.org/10.1039/D0SC02675A