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Acid-triggering of light-induced charge-separation in hybrid organic/inorganic molecular photoactive dyads for harnessing solar energy

Benazzi, Elisabetta ; Karlsson, Joshua ; Ben M'Barek, Youssef ; Chabera, Pavel LU ; Blanchard, Sébastien ; Alves, Sandra ; Proust, Anna ; Pullerits, Tönu LU ; Izzet, Guillaume and Gibson, Elizabeth A. (2021) In Inorganic Chemistry Frontiers 8(6). p.1610-1618
Abstract

H+ modulated charge-transfer in photoexcited covalent polyoxometalate-bodipy conjugates is described. The hybrid organic/inorganic molecular photoactive dyads are based on Keggin-type polyoxometalates (POMs, where KM = [PM11O39] and M = Mo or W) covalently grafted via an organotin linker to a bodipy (BOD) photosensitizer. The relative potentials of the photosensitizer and POM are aligned such that light-induced electron transfer from BOD to POM is permitted for the polyoxomolybdate KMoSn[BOD] but not effective for the polyoxotungstate analogue KWSn[BOD]. In both cases, the addition of acid shifts the redox potential of the POM only, to increase the driving force for electron transfer. This leads to charge-separation being switched on... (More)

H+ modulated charge-transfer in photoexcited covalent polyoxometalate-bodipy conjugates is described. The hybrid organic/inorganic molecular photoactive dyads are based on Keggin-type polyoxometalates (POMs, where KM = [PM11O39] and M = Mo or W) covalently grafted via an organotin linker to a bodipy (BOD) photosensitizer. The relative potentials of the photosensitizer and POM are aligned such that light-induced electron transfer from BOD to POM is permitted for the polyoxomolybdate KMoSn[BOD] but not effective for the polyoxotungstate analogue KWSn[BOD]. In both cases, the addition of acid shifts the redox potential of the POM only, to increase the driving force for electron transfer. This leads to charge-separation being switched on for KWSn[BOD] in the presence of acid. The addition of acid to KMoSn[BOD] accelerates charge-separation by an order of magnitude (from 2 ns to 200 ps) and is accompanied by a deceleration of charge recombination, leading to a charge-separated state lifetime of up to 1.3 μs. This behaviour is consistent with proton coupled electron transfer, which has previously been observed electrochemically for POMs, but this study shows, for the first time, the impact of protonation on photoinduced electron transfer. This journal is

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Contribution to journal
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published
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in
Inorganic Chemistry Frontiers
volume
8
issue
6
pages
9 pages
publisher
Royal Society of Chemistry
external identifiers
  • scopus:85103140027
ISSN
2052-1553
DOI
10.1039/d0qi01368d
language
English
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yes
id
43f16fe9-3ffe-4ce5-b724-00200516c6c5
date added to LUP
2021-04-07 14:21:59
date last changed
2021-04-08 12:01:39
@article{43f16fe9-3ffe-4ce5-b724-00200516c6c5,
  abstract     = {<p>H+ modulated charge-transfer in photoexcited covalent polyoxometalate-bodipy conjugates is described. The hybrid organic/inorganic molecular photoactive dyads are based on Keggin-type polyoxometalates (POMs, where KM = [PM11O39] and M = Mo or W) covalently grafted via an organotin linker to a bodipy (BOD) photosensitizer. The relative potentials of the photosensitizer and POM are aligned such that light-induced electron transfer from BOD to POM is permitted for the polyoxomolybdate KMoSn[BOD] but not effective for the polyoxotungstate analogue KWSn[BOD]. In both cases, the addition of acid shifts the redox potential of the POM only, to increase the driving force for electron transfer. This leads to charge-separation being switched on for KWSn[BOD] in the presence of acid. The addition of acid to KMoSn[BOD] accelerates charge-separation by an order of magnitude (from 2 ns to 200 ps) and is accompanied by a deceleration of charge recombination, leading to a charge-separated state lifetime of up to 1.3 μs. This behaviour is consistent with proton coupled electron transfer, which has previously been observed electrochemically for POMs, but this study shows, for the first time, the impact of protonation on photoinduced electron transfer. This journal is </p>},
  author       = {Benazzi, Elisabetta and Karlsson, Joshua and Ben M'Barek, Youssef and Chabera, Pavel and Blanchard, Sébastien and Alves, Sandra and Proust, Anna and Pullerits, Tönu and Izzet, Guillaume and Gibson, Elizabeth A.},
  issn         = {2052-1553},
  language     = {eng},
  number       = {6},
  pages        = {1610--1618},
  publisher    = {Royal Society of Chemistry},
  series       = {Inorganic Chemistry Frontiers},
  title        = {Acid-triggering of light-induced charge-separation in hybrid organic/inorganic molecular photoactive dyads for harnessing solar energy},
  url          = {http://dx.doi.org/10.1039/d0qi01368d},
  doi          = {10.1039/d0qi01368d},
  volume       = {8},
  year         = {2021},
}