Controlling Energy Levels and Blend Morphology for All-Polymer Solar Cells via Fluorination of a Naphthalene Diimide-Based Copolymer Acceptor

Mohammad Afsar Uddin, Youngkwon Kim, Robert Younts, Wonho Lee, Bhoj Gautam, Joonhyeong Choi, Cheng Wang, Kenan Gundogdu, Bumjoon J. Kim, Han Young Woo

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Abstract

We investigate the photovoltaic properties and charge dynamics of all polymer solar cells (all-PSCs) based on poly[(N,N'-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl)-alt-5,5′-(2,2′-bithiophene)] (P(NDI2OD-T2)) and its fluorinated analogue, poly[(N,N'-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl)-alt-5,5′-(3,3′-difluoro-2,2′-bithiophene)] (P(NDI2OD-T2F)), as the acceptor polymer and poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene-alt-5-octyl-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione] (PBDTTTPD) as the donor polymer. The PBDTTTPD:P(NDI2OD-T2)-based device has a high open-circuit voltage (VOC) of 1.03 V but suffers from low power conversion efficiency (PCE) of 2.02% with a short-circuit current density (JSC) and fill factor (FF) of 4.45 mA cm-2 and 0.44, respectively. In a stark contrast, the PCE of PBDTTTPD:P(NDI2OD-T2F)-based PSC dramatically increases to 6.09% (VOC = 1.00 V, JSC = 11.68 mA cm-2, and FF = 0.52). These results are attributed to the fluorination, which removes the energetic barrier for hole transfer and promotes the formation of the donor/acceptor blend morphology with suppressed phase separation and enhanced intermixed phases. The detailed charge dynamics examined by femtosecond transient absorption spectroscopy suggests the significantly increased hole transfer efficiency and larger populations of long-lived polarons for PBDTTTPD:P(NDI2OD-T2F).

Original languageEnglish
Pages (from-to)6374-6383
Number of pages10
JournalMacromolecules
Volume49
Issue number17
DOIs
Publication statusPublished - 2016 Sep 13

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Fluorination
Naphthalene
Volatile organic compounds
Electron energy levels
Conversion efficiency
Polymers
Copolymers
Polarons
Pyrroles
Open circuit voltage
Absorption spectroscopy
Phase separation
Short circuit currents
Current density
Polymer solar cells
naphthalenediimide
naphthalene

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

Cite this

Controlling Energy Levels and Blend Morphology for All-Polymer Solar Cells via Fluorination of a Naphthalene Diimide-Based Copolymer Acceptor. / Uddin, Mohammad Afsar; Kim, Youngkwon; Younts, Robert; Lee, Wonho; Gautam, Bhoj; Choi, Joonhyeong; Wang, Cheng; Gundogdu, Kenan; Kim, Bumjoon J.; Woo, Han Young.

In: Macromolecules, Vol. 49, No. 17, 13.09.2016, p. 6374-6383.

Research output: Contribution to journalArticle

Uddin, Mohammad Afsar ; Kim, Youngkwon ; Younts, Robert ; Lee, Wonho ; Gautam, Bhoj ; Choi, Joonhyeong ; Wang, Cheng ; Gundogdu, Kenan ; Kim, Bumjoon J. ; Woo, Han Young. / Controlling Energy Levels and Blend Morphology for All-Polymer Solar Cells via Fluorination of a Naphthalene Diimide-Based Copolymer Acceptor. In: Macromolecules. 2016 ; Vol. 49, No. 17. pp. 6374-6383.
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abstract = "We investigate the photovoltaic properties and charge dynamics of all polymer solar cells (all-PSCs) based on poly[(N,N'-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl)-alt-5,5′-(2,2′-bithiophene)] (P(NDI2OD-T2)) and its fluorinated analogue, poly[(N,N'-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl)-alt-5,5′-(3,3′-difluoro-2,2′-bithiophene)] (P(NDI2OD-T2F)), as the acceptor polymer and poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene-alt-5-octyl-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione] (PBDTTTPD) as the donor polymer. The PBDTTTPD:P(NDI2OD-T2)-based device has a high open-circuit voltage (VOC) of 1.03 V but suffers from low power conversion efficiency (PCE) of 2.02{\%} with a short-circuit current density (JSC) and fill factor (FF) of 4.45 mA cm-2 and 0.44, respectively. In a stark contrast, the PCE of PBDTTTPD:P(NDI2OD-T2F)-based PSC dramatically increases to 6.09{\%} (VOC = 1.00 V, JSC = 11.68 mA cm-2, and FF = 0.52). These results are attributed to the fluorination, which removes the energetic barrier for hole transfer and promotes the formation of the donor/acceptor blend morphology with suppressed phase separation and enhanced intermixed phases. The detailed charge dynamics examined by femtosecond transient absorption spectroscopy suggests the significantly increased hole transfer efficiency and larger populations of long-lived polarons for PBDTTTPD:P(NDI2OD-T2F).",
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T1 - Controlling Energy Levels and Blend Morphology for All-Polymer Solar Cells via Fluorination of a Naphthalene Diimide-Based Copolymer Acceptor

AU - Uddin, Mohammad Afsar

AU - Kim, Youngkwon

AU - Younts, Robert

AU - Lee, Wonho

AU - Gautam, Bhoj

AU - Choi, Joonhyeong

AU - Wang, Cheng

AU - Gundogdu, Kenan

AU - Kim, Bumjoon J.

AU - Woo, Han Young

PY - 2016/9/13

Y1 - 2016/9/13

N2 - We investigate the photovoltaic properties and charge dynamics of all polymer solar cells (all-PSCs) based on poly[(N,N'-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl)-alt-5,5′-(2,2′-bithiophene)] (P(NDI2OD-T2)) and its fluorinated analogue, poly[(N,N'-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl)-alt-5,5′-(3,3′-difluoro-2,2′-bithiophene)] (P(NDI2OD-T2F)), as the acceptor polymer and poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene-alt-5-octyl-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione] (PBDTTTPD) as the donor polymer. The PBDTTTPD:P(NDI2OD-T2)-based device has a high open-circuit voltage (VOC) of 1.03 V but suffers from low power conversion efficiency (PCE) of 2.02% with a short-circuit current density (JSC) and fill factor (FF) of 4.45 mA cm-2 and 0.44, respectively. In a stark contrast, the PCE of PBDTTTPD:P(NDI2OD-T2F)-based PSC dramatically increases to 6.09% (VOC = 1.00 V, JSC = 11.68 mA cm-2, and FF = 0.52). These results are attributed to the fluorination, which removes the energetic barrier for hole transfer and promotes the formation of the donor/acceptor blend morphology with suppressed phase separation and enhanced intermixed phases. The detailed charge dynamics examined by femtosecond transient absorption spectroscopy suggests the significantly increased hole transfer efficiency and larger populations of long-lived polarons for PBDTTTPD:P(NDI2OD-T2F).

AB - We investigate the photovoltaic properties and charge dynamics of all polymer solar cells (all-PSCs) based on poly[(N,N'-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl)-alt-5,5′-(2,2′-bithiophene)] (P(NDI2OD-T2)) and its fluorinated analogue, poly[(N,N'-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl)-alt-5,5′-(3,3′-difluoro-2,2′-bithiophene)] (P(NDI2OD-T2F)), as the acceptor polymer and poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene-alt-5-octyl-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione] (PBDTTTPD) as the donor polymer. The PBDTTTPD:P(NDI2OD-T2)-based device has a high open-circuit voltage (VOC) of 1.03 V but suffers from low power conversion efficiency (PCE) of 2.02% with a short-circuit current density (JSC) and fill factor (FF) of 4.45 mA cm-2 and 0.44, respectively. In a stark contrast, the PCE of PBDTTTPD:P(NDI2OD-T2F)-based PSC dramatically increases to 6.09% (VOC = 1.00 V, JSC = 11.68 mA cm-2, and FF = 0.52). These results are attributed to the fluorination, which removes the energetic barrier for hole transfer and promotes the formation of the donor/acceptor blend morphology with suppressed phase separation and enhanced intermixed phases. The detailed charge dynamics examined by femtosecond transient absorption spectroscopy suggests the significantly increased hole transfer efficiency and larger populations of long-lived polarons for PBDTTTPD:P(NDI2OD-T2F).

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