Photoinduced electron transfer between a carotenoid and TiO2 nanoparticle
(2002) In Journal of the American Chemical Society 124(46). p.13949-13957- Abstract
- The dynamics of photoinduced electron injection and recombination between all-trans-8'-apo-beta-caroten-8'-oic acid (ACOA) and a TiO2 Colloidal nanoparticle have been studied by means of transient absorption spectroscopy. We observed an ultrafast (similar to360 fs) electron injection from the initially excited S-2 state of ACOA into the TiO2 conduction band with a quantum yield of similar to40%. As a result, the ACOA(.+) radical cation was formed, as demonstrated by its intense absorption band centered at 840 nm. Because of the competing S-2-S-1 internal conversion, similar to60% of the S-2-state population relaxes to the S-1 state. Although the S-1 state is thermodynamically favorable to donate electrons to the TiO2, no evidence was found... (More)
- The dynamics of photoinduced electron injection and recombination between all-trans-8'-apo-beta-caroten-8'-oic acid (ACOA) and a TiO2 Colloidal nanoparticle have been studied by means of transient absorption spectroscopy. We observed an ultrafast (similar to360 fs) electron injection from the initially excited S-2 state of ACOA into the TiO2 conduction band with a quantum yield of similar to40%. As a result, the ACOA(.+) radical cation was formed, as demonstrated by its intense absorption band centered at 840 nm. Because of the competing S-2-S-1 internal conversion, similar to60% of the S-2-state population relaxes to the S-1 state. Although the S-1 state is thermodynamically favorable to donate electrons to the TiO2, no evidence was found for electron injection from the ACOA S, state, most likely as a result of a complicated electronic nature of the S, state, which decays with a similar to18 ps time constant to the ground state. The charge recombination between the injected electrons and the ACOA(.+) was found to be a highly nonexponential process extending from picoseconds to microseconds. Besides the usual pathway of charge recombination forming the ACOA ground state, about half of the ACOA(.+) recombines via the ACOA triplet state, which was monitored by its absorption band at 530 nm. This second channel of recombination proceeds on the nanosecond time scale, and the formed triplet state decays to the ground state with a lifetime of similar to7.3 mus. By examination of the process of photoinduced electron transfer in a carotenoid-semiconductor system, the results provide an insight into the photophysical properties of carotenoids, as well as evidence that the interfacial electron injection occurs from the initially populated excited state prior to electronic and nuclear relaxation of the carotenoid molecule. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/323401
- author
- Pan, Jie LU ; Benko, Gabor LU ; Xu, YH ; Pascher, Torbjörn LU ; Sun, LC ; Sundström, Villy LU and Polivka, Tomas LU
- organization
- publishing date
- 2002
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of the American Chemical Society
- volume
- 124
- issue
- 46
- pages
- 13949 - 13957
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- wos:000179269800057
- scopus:0037145995
- ISSN
- 1520-5126
- DOI
- 10.1021/ja0279186
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Chemical Physics (S) (011001060)
- id
- 8b6b31f6-3fe8-4b32-87be-e9eeec786255 (old id 323401)
- date added to LUP
- 2016-04-01 16:45:53
- date last changed
- 2022-01-28 22:01:16
@article{8b6b31f6-3fe8-4b32-87be-e9eeec786255,
abstract = {{The dynamics of photoinduced electron injection and recombination between all-trans-8'-apo-beta-caroten-8'-oic acid (ACOA) and a TiO2 Colloidal nanoparticle have been studied by means of transient absorption spectroscopy. We observed an ultrafast (similar to360 fs) electron injection from the initially excited S-2 state of ACOA into the TiO2 conduction band with a quantum yield of similar to40%. As a result, the ACOA(.+) radical cation was formed, as demonstrated by its intense absorption band centered at 840 nm. Because of the competing S-2-S-1 internal conversion, similar to60% of the S-2-state population relaxes to the S-1 state. Although the S-1 state is thermodynamically favorable to donate electrons to the TiO2, no evidence was found for electron injection from the ACOA S, state, most likely as a result of a complicated electronic nature of the S, state, which decays with a similar to18 ps time constant to the ground state. The charge recombination between the injected electrons and the ACOA(.+) was found to be a highly nonexponential process extending from picoseconds to microseconds. Besides the usual pathway of charge recombination forming the ACOA ground state, about half of the ACOA(.+) recombines via the ACOA triplet state, which was monitored by its absorption band at 530 nm. This second channel of recombination proceeds on the nanosecond time scale, and the formed triplet state decays to the ground state with a lifetime of similar to7.3 mus. By examination of the process of photoinduced electron transfer in a carotenoid-semiconductor system, the results provide an insight into the photophysical properties of carotenoids, as well as evidence that the interfacial electron injection occurs from the initially populated excited state prior to electronic and nuclear relaxation of the carotenoid molecule.}},
author = {{Pan, Jie and Benko, Gabor and Xu, YH and Pascher, Torbjörn and Sun, LC and Sundström, Villy and Polivka, Tomas}},
issn = {{1520-5126}},
language = {{eng}},
number = {{46}},
pages = {{13949--13957}},
publisher = {{The American Chemical Society (ACS)}},
series = {{Journal of the American Chemical Society}},
title = {{Photoinduced electron transfer between a carotenoid and TiO2 nanoparticle}},
url = {{http://dx.doi.org/10.1021/ja0279186}},
doi = {{10.1021/ja0279186}},
volume = {{124}},
year = {{2002}},
}