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

doi:10.1039/d0sc02675a

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^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

46 Citations (Scopus)

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 language	English
Pages (from-to)	8744-8756
Number of pages	13
Journal	Chemical Science
Volume	11
Issue number	33
DOIs	https://doi.org/10.1039/d0sc02675a
Publication status	Published - 7 Sept 2020

ASJC Scopus subject areas

General Chemistry

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@article{24e0d32dc6174f15a1f7816ab758f303,

title = "Structure-activity Relationships in Well-defined Conjugated Oligomer Photocatalysts for Hydrogen Production from Water",

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.",

author = "Aitchison, {Catherine M.} and Michael Sachs and Little, {Marc A.} and Liam Wilbraham and Brownbill, {Nick J.} and Kane, {Christopher M.} and Fr{\'e}d{\'e}ric Blanc and Zwijnenburg, {Martijn A.} and Durrant, {James R.} and Sprick, {Reiner Sebastian} and Cooper, {Andrew I.}",

note = "Funding Information: We thank the Engineering and Physical Sciences Research Council (EPSRC) for nancial support under Grant EP/N004884/ 1 and a PhD studentship to N. J. B. M. S. thanks Imperial College for a President's PhD Scholarship and is grateful to EPSRC for a Doctoral Prize Fellowship. The authors acknowledge Diamond Light Source for access to beamlines I19 (CY21726). Publisher Copyright: {\textcopyright} The Royal Society of Chemistry.",

year = "2020",

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day = "7",

doi = "10.1039/d0sc02675a",

language = "English",

volume = "11",

pages = "8744--8756",

journal = "Chemical Science",

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T1 - Structure-activity Relationships in Well-defined Conjugated Oligomer Photocatalysts for Hydrogen Production from Water

AU - Aitchison, Catherine M.

AU - Sachs, Michael

AU - Little, Marc A.

AU - Wilbraham, Liam

AU - Brownbill, Nick J.

AU - Kane, Christopher M.

AU - Blanc, Frédéric

AU - Zwijnenburg, Martijn A.

AU - Durrant, James R.

AU - Sprick, Reiner Sebastian

AU - Cooper, Andrew I.

N1 - Funding Information: We thank the Engineering and Physical Sciences Research Council (EPSRC) for nancial support under Grant EP/N004884/ 1 and a PhD studentship to N. J. B. M. S. thanks Imperial College for a President's PhD Scholarship and is grateful to EPSRC for a Doctoral Prize Fellowship. The authors acknowledge Diamond Light Source for access to beamlines I19 (CY21726). Publisher Copyright: © The Royal Society of Chemistry.

PY - 2020/9/7

Y1 - 2020/9/7

N2 - 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.

AB - 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.

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DO - 10.1039/d0sc02675a

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JO - Chemical Science

JF - Chemical Science

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Structure-activity Relationships in Well-defined Conjugated Oligomer Photocatalysts for Hydrogen Production from Water

Abstract

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