The University of Southampton
University of Southampton Institutional Repository

Photogeneration of spin quintet triplet–triplet excitations in DNA-assembled pentacene stacks‬

Photogeneration of spin quintet triplet–triplet excitations in DNA-assembled pentacene stacks‬
Photogeneration of spin quintet triplet–triplet excitations in DNA-assembled pentacene stacks‬
Singlet fission (SF), an exciton-doubling process observed in certain molecular semiconductors where two triplet excitons are generated from one singlet exciton, requires correctly tuned intermolecular coupling to allow separation of the two triplets to different molecular units. We explore this using DNA-encoded assembly of SF-capable pentacenes into discrete π-stacked constructs of defined size and geometry. Precise structural control is achieved via a combination of the DNA duplex formation between complementary single-stranded DNA and the local molecular geometry that directs the SF chromophores into a stable and predictable slip-stacked configuration, as confirmed by molecular dynamics (MD) modeling. Transient electron spin resonance spectroscopy revealed that within these DNA-assembled pentacene stacks, SF evolves via a bound triplet pair quintet state, which subsequently converts into free triplets. SF evolution via a long-lived quintet state sets specific requirements on intermolecular coupling, rendering the quintet spectrum and its zero-field-splitting parameters highly sensitive to intermolecular geometry. We have found that the experimental spectra and zero-field-splitting parameters are consistent with a slight systematic strain relative to the MD-optimized geometry. Thus, the transient electron spin resonance analysis is a powerful tool to test and refine the MD-derived structure models. DNA-encoded assembly of coupled semiconductor molecules allows controlled construction of electronically functional structures, but brings with it significant dynamic and polar disorders. Our findings here of efficient SF through quintet states demonstrate that these conditions still allow efficient and controlled semiconductor operation and point toward future opportunities for constructing functional optoelectronic systems.
0002-7863
5431–5438
Osborne, Sarah R.E.
5a8cf935-9d05-4a8c-a765-014691a548bb
Gorman, Jeffrey
8c835a05-fa3c-4d8b-b5af-c451a3560063
Weiss, Leah R
adc43dab-90df-496b-ba83-e0ee2739f547
Sridhar, Akshay
1fe81f1b-570f-4b91-af78-144ff7c7bec9
Panjwani, Naitik A.
3e70cad6-c30b-46d0-bc6a-a2680fda3d76
Divitini, Giorgio
627cd6c9-60c1-481c-9bca-84824e7547b3
Budden, Peter
f12b71cb-4d5c-4ec1-96b8-8510a191980c
Palecek, David
42ac438f-feec-4240-a0d1-2f5baf40f412
Ryan, Seán T. J.
bd6edec8-2d18-4278-95f9-d996b8367745
Rao, Akshay
762aef3b-3b81-4a20-9462-872773663ac4
Collepardo-Guevara, Rosana
93893d22-acea-4dd3-b1fd-fbf6e7f1b394
El-Sagheer, Afaf
05b8295a-64ad-4fdf-ad57-c34934a46c04
Brown, Tom
a64aae36-bb30-42df-88a2-11be394e8c89
Behrends, Jan
6386feb4-e2e1-4d4b-bc65-a7fe40415e4d
Friend, Richard H.
9c1c55d5-efff-41b4-a055-de8312b6b580
Auras, Florian
a56e7a96-fe76-4b9e-acd0-209f720a0a3e
Osborne, Sarah R.E.
5a8cf935-9d05-4a8c-a765-014691a548bb
Gorman, Jeffrey
8c835a05-fa3c-4d8b-b5af-c451a3560063
Weiss, Leah R
adc43dab-90df-496b-ba83-e0ee2739f547
Sridhar, Akshay
1fe81f1b-570f-4b91-af78-144ff7c7bec9
Panjwani, Naitik A.
3e70cad6-c30b-46d0-bc6a-a2680fda3d76
Divitini, Giorgio
627cd6c9-60c1-481c-9bca-84824e7547b3
Budden, Peter
f12b71cb-4d5c-4ec1-96b8-8510a191980c
Palecek, David
42ac438f-feec-4240-a0d1-2f5baf40f412
Ryan, Seán T. J.
bd6edec8-2d18-4278-95f9-d996b8367745
Rao, Akshay
762aef3b-3b81-4a20-9462-872773663ac4
Collepardo-Guevara, Rosana
93893d22-acea-4dd3-b1fd-fbf6e7f1b394
El-Sagheer, Afaf
05b8295a-64ad-4fdf-ad57-c34934a46c04
Brown, Tom
a64aae36-bb30-42df-88a2-11be394e8c89
Behrends, Jan
6386feb4-e2e1-4d4b-bc65-a7fe40415e4d
Friend, Richard H.
9c1c55d5-efff-41b4-a055-de8312b6b580
Auras, Florian
a56e7a96-fe76-4b9e-acd0-209f720a0a3e

Osborne, Sarah R.E., Gorman, Jeffrey, Weiss, Leah R, Sridhar, Akshay, Panjwani, Naitik A., Divitini, Giorgio, Budden, Peter, Palecek, David, Ryan, Seán T. J., Rao, Akshay, Collepardo-Guevara, Rosana, El-Sagheer, Afaf, Brown, Tom, Behrends, Jan, Friend, Richard H. and Auras, Florian (2023) Photogeneration of spin quintet triplet–triplet excitations in DNA-assembled pentacene stacks‬. Journal of the American Chemical Society, 145 (9), 5431–5438. (doi:10.1021/jacs.2c13743).

Record type: Article

Abstract

Singlet fission (SF), an exciton-doubling process observed in certain molecular semiconductors where two triplet excitons are generated from one singlet exciton, requires correctly tuned intermolecular coupling to allow separation of the two triplets to different molecular units. We explore this using DNA-encoded assembly of SF-capable pentacenes into discrete π-stacked constructs of defined size and geometry. Precise structural control is achieved via a combination of the DNA duplex formation between complementary single-stranded DNA and the local molecular geometry that directs the SF chromophores into a stable and predictable slip-stacked configuration, as confirmed by molecular dynamics (MD) modeling. Transient electron spin resonance spectroscopy revealed that within these DNA-assembled pentacene stacks, SF evolves via a bound triplet pair quintet state, which subsequently converts into free triplets. SF evolution via a long-lived quintet state sets specific requirements on intermolecular coupling, rendering the quintet spectrum and its zero-field-splitting parameters highly sensitive to intermolecular geometry. We have found that the experimental spectra and zero-field-splitting parameters are consistent with a slight systematic strain relative to the MD-optimized geometry. Thus, the transient electron spin resonance analysis is a powerful tool to test and refine the MD-derived structure models. DNA-encoded assembly of coupled semiconductor molecules allows controlled construction of electronically functional structures, but brings with it significant dynamic and polar disorders. Our findings here of efficient SF through quintet states demonstrate that these conditions still allow efficient and controlled semiconductor operation and point toward future opportunities for constructing functional optoelectronic systems.

Text
jacs.2c13743 - Version of Record
Available under License Creative Commons Attribution.
Download (4MB)

More information

Accepted/In Press date: 24 February 2023
e-pub ahead of print date: 24 February 2023
Published date: 8 March 2023
Additional Information: This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 670405). This work has been performed using resources provided by the Cambridge Tier-2 system operated by the University of Cambridge Research Computing Service (http://www.hpc.cam.ac.uk), funded by the EPSRC Tier-2 capital grant EP/P020259/1. A.S. and R.C.G. thank funding from the Winton Advanced Research Programme for the Physics of Sustainability. R.H.F., F.A., and Y.L. acknowledge support from the Simons Foundation (grant 601946). L.R.W. thanks funding from the UChicago/AIMR joint research center. A.E.-S. and T.B. acknowledge funding from UK BBSRC grant BB/R008655/1. The authors acknowledge Anthony J. Petty II and John E. Anthony for fruitful discussion on pentacene mesylation and azidification and for providing the 2,9-dibromopentacene.

Identifiers

Local EPrints ID: 476962
URI: http://eprints.soton.ac.uk/id/eprint/476962
ISSN: 0002-7863
PURE UUID: dd821a78-88cc-4062-bef2-51e621e269ff
ORCID for Afaf El-Sagheer: ORCID iD orcid.org/0000-0001-8706-1292

Catalogue record

Date deposited: 22 May 2023 16:58
Last modified: 17 Mar 2024 03:04

Export record

Altmetrics

Contributors

Author: Sarah R.E. Osborne
Author: Jeffrey Gorman
Author: Leah R Weiss
Author: Akshay Sridhar
Author: Naitik A. Panjwani
Author: Giorgio Divitini
Author: Peter Budden
Author: David Palecek
Author: Seán T. J. Ryan
Author: Akshay Rao
Author: Rosana Collepardo-Guevara
Author: Afaf El-Sagheer ORCID iD
Author: Tom Brown
Author: Jan Behrends
Author: Richard H. Friend
Author: Florian Auras

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×