Correlating photovoltaic properties of PTB7-Th:PC71BM blend to photophysics and microstructure as a function of thermal annealing

Lethy Krishnan Jagadamma; Muhammad Tariq Sajjad; Victoria  Savikhin; Michael  Toney; Ifor D. W. Samuel

doi:10.1039/C7TA03144K

Correlating photovoltaic properties of PTB7-Th:PC71BM blend to photophysics and microstructure as a function of thermal annealing

Lethy Krishnan Jagadamma, Muhammad Tariq Sajjad, Victoria Savikhin , Michael Toney, Ifor D. W. Samuel

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

Abstract

Selective optimisation of light harvesting materials and interface properties has brought breakthroughs in power conversion efficiency (11-12 %) of organic photovoltaics (OPVs). However to translate this promising efficiency to economically viable applications, long term stability is a fundamental requirement. A number of degradation pathways, both extrinsic and intrinsic, reduce the long term stability of OPVs. Here, the photovoltaic properties of a highly efficient bulk heterojunction PTB7-Th:PC71BM blend were investigated as a function of thermal annealing. The changes in charge generation, separation, and transport due to thermal annealing were measured and related to changes in the microstructure and photovoltaic performance. A 30 % drop in power conversion efficiency of PTB7-Th:PC71BM blends upon thermal annealing at 150 oC was identified as mainly due to morphological instability induced by strong phase separation of donor and acceptor molecules of the blend films. Based on the insight gained from these investigations, enhanced thermal stability was demonstrated by replacing the PC71BM fullerene acceptor with the non-fullerene acceptor ITIC, for which power conversion efficiency dropped only by 9 % upon thermal annealing at 150 oC.

Original language	English
Pages (from-to)	14646-14657
Number of pages	12
Journal	Journal of Materials Chemistry A
Volume	5
Issue number	28
Early online date	8 Jun 2017
DOIs	https://doi.org/10.1039/C7TA03144K
Publication status	Published - 28 Jul 2017

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© 2017, Royal Society of Chemistry. 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.rsc.org / https://doi.org/10.1039/C7TA03144K
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Self-Assembled Organic Photovoltaic mat: Self-assembled organic photovoltaic materials
Samuel, I. D. W. (PI)
EPSRC
17/03/14 → 16/03/17
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Lethy Krishnan Jagadamma
- lkj2st-andrews.acuk
Person: Academic, Academic - Research

Correlating photovoltaic properties of PTB7-Th:PC71BM blend to photophysics and microstructure as a function of thermal annealing (dataset)
Krishnan Jagadamma, L. (Creator), Sajjad, M. T. (Creator), Savikhin, V. (Creator), Toney, M. F. (Creator) & Samuel, I. D. W. (Creator), University of St Andrews, 17 Jul 2017
DOI: 10.17630/eadf56f3-8c70-47da-ac6d-67f2d78b3f74
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title = "Correlating photovoltaic properties of PTB7-Th:PC71BM blend to photophysics and microstructure as a function of thermal annealing",

abstract = "Selective optimisation of light harvesting materials and interface properties has brought breakthroughs in power conversion efficiency (11-12 %) of organic photovoltaics (OPVs). However to translate this promising efficiency to economically viable applications, long term stability is a fundamental requirement. A number of degradation pathways, both extrinsic and intrinsic, reduce the long term stability of OPVs. Here, the photovoltaic properties of a highly efficient bulk heterojunction PTB7-Th:PC71BM blend were investigated as a function of thermal annealing. The changes in charge generation, separation, and transport due to thermal annealing were measured and related to changes in the microstructure and photovoltaic performance. A 30 % drop in power conversion efficiency of PTB7-Th:PC71BM blends upon thermal annealing at 150 oC was identified as mainly due to morphological instability induced by strong phase separation of donor and acceptor molecules of the blend films. Based on the insight gained from these investigations, enhanced thermal stability was demonstrated by replacing the PC71BM fullerene acceptor with the non-fullerene acceptor ITIC, for which power conversion efficiency dropped only by 9 % upon thermal annealing at 150 oC.",

author = "{Krishnan Jagadamma}, Lethy and Sajjad, {Muhammad Tariq} and Victoria Savikhin and Michael Toney and Samuel, {Ifor D. W.}",

note = "We acknowledge support from EPSRC (grant number EP/L012294/1) and the European Research Council (grant number 321305). I.D.W.S. also acknowledges a Royal Society Wolfson Research Merit Award. VS acknowledges support from the Office of Naval Research NDSEG fellowship. Research data supporting this paper is available at doi http://dx.doi.org/10.17630/eadf56f3-8c70-47da-ac6d-67f2d78b3f74",

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AU - Krishnan Jagadamma, Lethy

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AU - Savikhin , Victoria

AU - Toney, Michael

AU - Samuel, Ifor D. W.

N1 - We acknowledge support from EPSRC (grant number EP/L012294/1) and the European Research Council (grant number 321305). I.D.W.S. also acknowledges a Royal Society Wolfson Research Merit Award. VS acknowledges support from the Office of Naval Research NDSEG fellowship. Research data supporting this paper is available at doi http://dx.doi.org/10.17630/eadf56f3-8c70-47da-ac6d-67f2d78b3f74

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N2 - Selective optimisation of light harvesting materials and interface properties has brought breakthroughs in power conversion efficiency (11-12 %) of organic photovoltaics (OPVs). However to translate this promising efficiency to economically viable applications, long term stability is a fundamental requirement. A number of degradation pathways, both extrinsic and intrinsic, reduce the long term stability of OPVs. Here, the photovoltaic properties of a highly efficient bulk heterojunction PTB7-Th:PC71BM blend were investigated as a function of thermal annealing. The changes in charge generation, separation, and transport due to thermal annealing were measured and related to changes in the microstructure and photovoltaic performance. A 30 % drop in power conversion efficiency of PTB7-Th:PC71BM blends upon thermal annealing at 150 oC was identified as mainly due to morphological instability induced by strong phase separation of donor and acceptor molecules of the blend films. Based on the insight gained from these investigations, enhanced thermal stability was demonstrated by replacing the PC71BM fullerene acceptor with the non-fullerene acceptor ITIC, for which power conversion efficiency dropped only by 9 % upon thermal annealing at 150 oC.

AB - Selective optimisation of light harvesting materials and interface properties has brought breakthroughs in power conversion efficiency (11-12 %) of organic photovoltaics (OPVs). However to translate this promising efficiency to economically viable applications, long term stability is a fundamental requirement. A number of degradation pathways, both extrinsic and intrinsic, reduce the long term stability of OPVs. Here, the photovoltaic properties of a highly efficient bulk heterojunction PTB7-Th:PC71BM blend were investigated as a function of thermal annealing. The changes in charge generation, separation, and transport due to thermal annealing were measured and related to changes in the microstructure and photovoltaic performance. A 30 % drop in power conversion efficiency of PTB7-Th:PC71BM blends upon thermal annealing at 150 oC was identified as mainly due to morphological instability induced by strong phase separation of donor and acceptor molecules of the blend films. Based on the insight gained from these investigations, enhanced thermal stability was demonstrated by replacing the PC71BM fullerene acceptor with the non-fullerene acceptor ITIC, for which power conversion efficiency dropped only by 9 % upon thermal annealing at 150 oC.

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Correlating photovoltaic properties of PTB7-Th:PC71BM blend to photophysics and microstructure as a function of thermal annealing

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Correlating photovoltaic properties of PTB7-Th:PC71BM blend to photophysics and microstructure as a function of thermal annealing (dataset)

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