Barrierless slow dissociation of photogenerated charge pairs in high-performance polymer-fullerene solar cells

Dimali A. Vithanage; Andrew B. Matheson; Vytenis Pranculis; Gordon J. Hedley; Scott J. Pearson; Vidmantas   Gulbinas; Ifor D. W. Samuel; Arvydas Ruseckas

doi:10.1021/acs.jpcc.7b04868

Barrierless slow dissociation of photogenerated charge pairs in high-performance polymer-fullerene solar cells

Dimali A. Vithanage, Andrew B. Matheson, Vytenis Pranculis, Gordon J. Hedley, Scott J. Pearson, Vidmantas Gulbinas, Ifor D. W. Samuel, Arvydas Ruseckas

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

Abstract

Broadband transient absorption spectroscopy is combined with ultrafast carrier drift measurements to study dissociation of photogenerated charge pairs in efficient photovoltaic blends of the electron donating polymer PTB7 with the acceptor PC₇₁BM. A high ensemble-average mobility sum of electrons and holes is observed which is independent of applied electric field above 12 V/μm and indicates nearly barrier-less pair dissociation at room temperature on a picosecond time scale. High efficiency of pair dissociation in this material is achieved by a combination of high electron mobility in fullerene clusters and hole delocalization along the polymer chain which increases by 30% during dissociation. Our results suggest a predominantly diffusive charge pair dissociation mechanism which requires persistent mobility of both carriers and preferably some delocalization of at least one of them.

Original language	English
Pages (from-to)	14060-14065
Number of pages	6
Journal	Journal of Physical Chemistry C
Volume	121
Issue number	26
Early online date	1 Jun 2017
DOIs	https://doi.org/10.1021/acs.jpcc.7b04868
Publication status	Published - 6 Jul 2017

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10.1021/acs.jpcc.7b04868

Vithanage-2017-Barrier-less-JPC-AAM
© 2017, American Chemical Society. This work has been made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at pubs.acs.org / https://doi.org/10.1021/acs.jpcc.7b04868
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Vithanage-2017-Barrier-less-JPC-SIAccepted author manuscript, 606 KB

Equipment Account: Characterisation and Manipulation of Advanced Functional Materials and their Interfaces at the Nanoscale
Samuel, I. D. W. (PI)
EPSRC
1/10/13 → 30/09/23
Project: Standard
ERC Advanced Grant EXCITON: EU FP7 ERC Advanced Grant 2012 EXCITON
Samuel, I. D. W. (PI)
European Research Council
1/04/13 → 30/03/19
Project: Standard
The Influence of Excited State Physics: The influence of Excited State Physics in Conjugated Polymer Devices
Samuel, I. D. W. (PI)
EPSRC
1/10/12 → 30/09/15
Project: Standard

Barrierless Slow Dissociation of Photogenerated Charge Pairs in High-Performance Polymer-Fullerene Solar Cells (dataset)
Vithanage, C. D. A. (Creator), Matheson, A. B. (Creator), Pranculis, V. (Creator), Hedley, G. J. (Creator), Pearson, S. J. (Creator), Gulbinas, V. (Creator), Samuel, I. D. W. (Creator) & Ruseckas, A. (Creator), University of St Andrews, 2017
DOI: 10.17630/7ec84b4b-d2ab-493c-aaf6-5503a44c0eb5
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Cite this

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title = "Barrierless slow dissociation of photogenerated charge pairs in high-performance polymer-fullerene solar cells",

abstract = "Broadband transient absorption spectroscopy is combined with ultrafast carrier drift measurements to study dissociation of photogenerated charge pairs in efficient photovoltaic blends of the electron donating polymer PTB7 with the acceptor PC71BM. A high ensemble-average mobility sum of electrons and holes is observed which is independent of applied electric field above 12 V/μm and indicates nearly barrier-less pair dissociation at room temperature on a picosecond time scale. High efficiency of pair dissociation in this material is achieved by a combination of high electron mobility in fullerene clusters and hole delocalization along the polymer chain which increases by 30% during dissociation. Our results suggest a predominantly diffusive charge pair dissociation mechanism which requires persistent mobility of both carriers and preferably some delocalization of at least one of them. ",

author = "Vithanage, {Dimali A.} and Matheson, {Andrew B.} and Vytenis Pranculis and Hedley, {Gordon J.} and Pearson, {Scott J.} and Vidmantas Gulbinas and Samuel, {Ifor D. W.} and Arvydas Ruseckas",

note = "The work in St Andrews was supported by the Engineering and Physical Sciences Research Council (grants EP/L017008/1, EP/J009016/1 and EP/G03673X/1) and the European Research Council (grant 321305). The work in Vilnius was supported by the Research Council of Lithuania (project MIP-85/2015). I.D.W.S. acknowledges support from a Royal Society Wolfson Research Merit Award. D.A.V. is grateful to Supergen SuperSolar Hub for the travel grant. The research data supporting this publication can be accessed at http://dx.doi.org/10.17630/7ec84b4b-d2ab-493c-aaf6-5503a44c0eb5",

year = "2017",

month = jul,

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doi = "10.1021/acs.jpcc.7b04868",

language = "English",

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T1 - Barrierless slow dissociation of photogenerated charge pairs in high-performance polymer-fullerene solar cells

AU - Vithanage, Dimali A.

AU - Matheson, Andrew B.

AU - Pranculis, Vytenis

AU - Hedley, Gordon J.

AU - Pearson, Scott J.

AU - Gulbinas, Vidmantas

AU - Samuel, Ifor D. W.

AU - Ruseckas, Arvydas

N1 - The work in St Andrews was supported by the Engineering and Physical Sciences Research Council (grants EP/L017008/1, EP/J009016/1 and EP/G03673X/1) and the European Research Council (grant 321305). The work in Vilnius was supported by the Research Council of Lithuania (project MIP-85/2015). I.D.W.S. acknowledges support from a Royal Society Wolfson Research Merit Award. D.A.V. is grateful to Supergen SuperSolar Hub for the travel grant. The research data supporting this publication can be accessed at http://dx.doi.org/10.17630/7ec84b4b-d2ab-493c-aaf6-5503a44c0eb5

PY - 2017/7/6

Y1 - 2017/7/6

N2 - Broadband transient absorption spectroscopy is combined with ultrafast carrier drift measurements to study dissociation of photogenerated charge pairs in efficient photovoltaic blends of the electron donating polymer PTB7 with the acceptor PC71BM. A high ensemble-average mobility sum of electrons and holes is observed which is independent of applied electric field above 12 V/μm and indicates nearly barrier-less pair dissociation at room temperature on a picosecond time scale. High efficiency of pair dissociation in this material is achieved by a combination of high electron mobility in fullerene clusters and hole delocalization along the polymer chain which increases by 30% during dissociation. Our results suggest a predominantly diffusive charge pair dissociation mechanism which requires persistent mobility of both carriers and preferably some delocalization of at least one of them.

AB - Broadband transient absorption spectroscopy is combined with ultrafast carrier drift measurements to study dissociation of photogenerated charge pairs in efficient photovoltaic blends of the electron donating polymer PTB7 with the acceptor PC71BM. A high ensemble-average mobility sum of electrons and holes is observed which is independent of applied electric field above 12 V/μm and indicates nearly barrier-less pair dissociation at room temperature on a picosecond time scale. High efficiency of pair dissociation in this material is achieved by a combination of high electron mobility in fullerene clusters and hole delocalization along the polymer chain which increases by 30% during dissociation. Our results suggest a predominantly diffusive charge pair dissociation mechanism which requires persistent mobility of both carriers and preferably some delocalization of at least one of them.

U2 - 10.1021/acs.jpcc.7b04868

DO - 10.1021/acs.jpcc.7b04868

M3 - Article

SN - 1932-7447

VL - 121

SP - 14060

EP - 14065

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

IS - 26

ER -

Barrierless slow dissociation of photogenerated charge pairs in high-performance polymer-fullerene solar cells

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Projects

Equipment Account: Characterisation and Manipulation of Advanced Functional Materials and their Interfaces at the Nanoscale

ERC Advanced Grant EXCITON: EU FP7 ERC Advanced Grant 2012 EXCITON

The Influence of Excited State Physics: The influence of Excited State Physics in Conjugated Polymer Devices

Datasets

Barrierless Slow Dissociation of Photogenerated Charge Pairs in High-Performance Polymer-Fullerene Solar Cells (dataset)

Cite this