Correlating photovoltaic properties of PTB7-Th:PC71BM blend to photophysics and microstructure as a function of thermal annealing
Journal article
Jagadamma, Lethy Krishnan, Sajjad, Muhammad T, Savikhin, Victoria, Toney, Michael F, Samuel, Ifor DW and Sajjad, T (2017). Correlating photovoltaic properties of PTB7-Th:PC71BM blend to photophysics and microstructure as a function of thermal annealing. Journal of Materials Chemistry A. 5 (28), pp. 14646-14657. https://doi.org/10.1039/C7TA03144K
Authors | Jagadamma, Lethy Krishnan, Sajjad, Muhammad T, Savikhin, Victoria, Toney, Michael F, Samuel, Ifor DW and Sajjad, T |
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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 ex situ 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 the power conversion efficiency of PTB7-Th:PC71BM blends upon thermal annealing at 150 °C 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 a non-fullerene acceptor ITIC, for which power conversion efficiency dropped only by 9% upon thermal annealing at 150 °C. |
Year | 2017 |
Journal | Journal of Materials Chemistry A |
Journal citation | 5 (28), pp. 14646-14657 |
Publisher | Royal Society of Chemistry (RSC) |
ISSN | 2050-7488 |
Digital Object Identifier (DOI) | https://doi.org/10.1039/C7TA03144K |
Publication dates | |
08 Jun 2017 | |
Online | 08 Jun 2017 |
Publication process dates | |
Accepted | 04 Jun 2017 |
Deposited | 05 Feb 2020 |
Accepted author manuscript | License File Access Level Open |
https://openresearch.lsbu.ac.uk/item/88z7x
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Accepted author manuscript
KrishnanJagadamma_2017_JMCA_Photophysics_AAM.pdf | ||
License: CC BY 4.0 | ||
File access level: Open |
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