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Title: Closely packed, low reorganization energy $π$-extended postfullerene acceptors for efficient polymer solar cells

Abstract

New organic semiconductors are essential for developing inexpensive, high-efficiency, solution-processable polymer solar cells (PSCs). PSC photoactive layers are typically fabricated by film-casting a donor polymer and a fullerene acceptor blend, with ensuing solvent evaporation and phase separation creating discrete conduits for photogenerated holes and electrons. Until recently, n-type fullerene acceptors dominated the PSC literature; however, indacenodithienothiophene (IDTT)-based acceptors have recently enabled remarkable PSC performance metrics, for reasons that are not entirely obvious. Herein we report two isomeric IDTT-based acceptors 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-benz-(5, 6)indanone))-5,5,11,11-tetrakis(4-nonylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]di-thiophene (ITN-C9) and 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-benz(6,7)indanone))-5,5,11,11-tetrakis(4-nonylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene (ITzN-C9) that shed light on the exceptional IDTT properties vis-à-vis fullerenes. The neat acceptors and blends with fluoropolymer donor poly{[4,8-bis[5-(2- ethylhexyl)-4-fluoro-2-thienyl]benzo[1,2-b:4,5-b′]dithiophene2,6-diyl]-alt-[2,5-thiophenediyl[5,7-bis(2-ethylhexyl)-4,8-dioxo4H,8H-benzo[1,2-c:4,5-c′]dithiophene-1,3-diyl]]} (PBDB-TF) are investigated by optical spectroscopy, cyclic voltammetry, thermogravimetric analysis, differential scanning calorimetry, single-crystal X-ray diffraction, photovoltaic response, space-charge-limited current transport, atomic force microscopy, grazing incidence wide-angle X-ray scattering, and density functional theory-level quantum chemical analysis. The data reveal that ITN-C9 and ITzN-C9 organize such that the lowest unoccupied molecular orbital-rich end groups have intermolecular π−π distances as close as 3.31(1) Å, with electronic coupling integrals as large as 38 meV, and internal reorganization energies as small as 0.133 eV, comparable to or superior to those in fullerenes. ITN-C9 and ITzN-C9 have broad solar-relevant opticalmore » absorption, and, when blended with PBDB-TF, afford devices with power conversion efficiencies near 10%. Performance differences between ITN-C9 and ITzN-C9 are understandable in terms of molecular and electronic structure distinctions via the influences on molecular packing and orientation with respect to the electrode.« less

Authors:
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Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Center for Light Energy Activated Redox Processes (LEAP); Northwestern Univ., Evanston, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); Ministerio de Economia y Competitividad; National Institute of Standards and Technology (NIST); National Science Foundation (NSF)
OSTI Identifier:
1465253
Alternate Identifier(s):
OSTI ID: 1485679
Grant/Contract Number:  
SC0001059; AC02-06CH11357; CTQ2015-66897-P; 70NANB14H012; 1542205
Resource Type:
Journal Article: Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Volume: 115 Journal Issue: 36; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; solar energy; organic photovoltaic; small molecule acceptor; single crystal; molecular modeling

Citation Formats

Swick, Steven M., Zhu, Weigang, Matta, Micaela, Aldrich, Thomas J., Harbuzaru, Alexandra, Lopez Navarrete, J. Teodomiro, Ponce Ortiz, Rocio, Kohlstedt, Kevin L., Schatz, George C., Facchetti, Antonio, Melkonyan, Ferdinand S., and Marks, Tobin J. Closely packed, low reorganization energy $π$-extended postfullerene acceptors for efficient polymer solar cells. United States: N. p., 2018. Web. doi:10.1073/pnas.1807535115.
Swick, Steven M., Zhu, Weigang, Matta, Micaela, Aldrich, Thomas J., Harbuzaru, Alexandra, Lopez Navarrete, J. Teodomiro, Ponce Ortiz, Rocio, Kohlstedt, Kevin L., Schatz, George C., Facchetti, Antonio, Melkonyan, Ferdinand S., & Marks, Tobin J. Closely packed, low reorganization energy $π$-extended postfullerene acceptors for efficient polymer solar cells. United States. doi:10.1073/pnas.1807535115.
Swick, Steven M., Zhu, Weigang, Matta, Micaela, Aldrich, Thomas J., Harbuzaru, Alexandra, Lopez Navarrete, J. Teodomiro, Ponce Ortiz, Rocio, Kohlstedt, Kevin L., Schatz, George C., Facchetti, Antonio, Melkonyan, Ferdinand S., and Marks, Tobin J. Mon . "Closely packed, low reorganization energy $π$-extended postfullerene acceptors for efficient polymer solar cells". United States. doi:10.1073/pnas.1807535115.
@article{osti_1465253,
title = {Closely packed, low reorganization energy $π$-extended postfullerene acceptors for efficient polymer solar cells},
author = {Swick, Steven M. and Zhu, Weigang and Matta, Micaela and Aldrich, Thomas J. and Harbuzaru, Alexandra and Lopez Navarrete, J. Teodomiro and Ponce Ortiz, Rocio and Kohlstedt, Kevin L. and Schatz, George C. and Facchetti, Antonio and Melkonyan, Ferdinand S. and Marks, Tobin J.},
abstractNote = {New organic semiconductors are essential for developing inexpensive, high-efficiency, solution-processable polymer solar cells (PSCs). PSC photoactive layers are typically fabricated by film-casting a donor polymer and a fullerene acceptor blend, with ensuing solvent evaporation and phase separation creating discrete conduits for photogenerated holes and electrons. Until recently, n-type fullerene acceptors dominated the PSC literature; however, indacenodithienothiophene (IDTT)-based acceptors have recently enabled remarkable PSC performance metrics, for reasons that are not entirely obvious. Herein we report two isomeric IDTT-based acceptors 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-benz-(5, 6)indanone))-5,5,11,11-tetrakis(4-nonylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]di-thiophene (ITN-C9) and 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-benz(6,7)indanone))-5,5,11,11-tetrakis(4-nonylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene (ITzN-C9) that shed light on the exceptional IDTT properties vis-à-vis fullerenes. The neat acceptors and blends with fluoropolymer donor poly{[4,8-bis[5-(2- ethylhexyl)-4-fluoro-2-thienyl]benzo[1,2-b:4,5-b′]dithiophene2,6-diyl]-alt-[2,5-thiophenediyl[5,7-bis(2-ethylhexyl)-4,8-dioxo4H,8H-benzo[1,2-c:4,5-c′]dithiophene-1,3-diyl]]} (PBDB-TF) are investigated by optical spectroscopy, cyclic voltammetry, thermogravimetric analysis, differential scanning calorimetry, single-crystal X-ray diffraction, photovoltaic response, space-charge-limited current transport, atomic force microscopy, grazing incidence wide-angle X-ray scattering, and density functional theory-level quantum chemical analysis. The data reveal that ITN-C9 and ITzN-C9 organize such that the lowest unoccupied molecular orbital-rich end groups have intermolecular π−π distances as close as 3.31(1) Å, with electronic coupling integrals as large as 38 meV, and internal reorganization energies as small as 0.133 eV, comparable to or superior to those in fullerenes. ITN-C9 and ITzN-C9 have broad solar-relevant optical absorption, and, when blended with PBDB-TF, afford devices with power conversion efficiencies near 10%. Performance differences between ITN-C9 and ITzN-C9 are understandable in terms of molecular and electronic structure distinctions via the influences on molecular packing and orientation with respect to the electrode.},
doi = {10.1073/pnas.1807535115},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
issn = {0027-8424},
number = 36,
volume = 115,
place = {United States},
year = {2018},
month = {8}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1073/pnas.1807535115

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Works referenced in this record:

Mesoscale molecular network formation in amorphous organic materials
journal, June 2014

  • Savoie, B. M.; Kohlstedt, K. L.; Jackson, N. E.
  • Proceedings of the National Academy of Sciences, Vol. 111, Issue 28
  • DOI: 10.1073/pnas.1409514111

Alkyl Side-Chain Engineering in Wide-Bandgap Copolymers Leading to Power Conversion Efficiencies over 10%
journal, December 2016


Ambipolarity and Dimensionality of Charge Transport in Crystalline Group 14 Phthalocyanines: A Computational Study
journal, January 2018

  • Gali, Sai Manoj; Matta, Micaela; Lessard, Benoît H.
  • The Journal of Physical Chemistry C, Vol. 122, Issue 5
  • DOI: 10.1021/acs.jpcc.7b11588

Fullerene derivative acceptors for high performance polymer solar cells
journal, January 2011

  • He, Youjun; Li, Yongfang
  • Phys. Chem. Chem. Phys., Vol. 13, Issue 6
  • DOI: 10.1039/C0CP01178A

The ORCA program system: The ORCA program system
journal, June 2011

  • Neese, Frank
  • Wiley Interdisciplinary Reviews: Computational Molecular Science, Vol. 2, Issue 1
  • DOI: 10.1002/wcms.81

A General Route to Enhance Polymer Solar Cell Performance using Plasmonic Nanoprisms
journal, March 2014

  • Yao, Kai; Salvador, Michael; Chueh, Chu-Chen
  • Advanced Energy Materials, Vol. 4, Issue 9, Article No. 1400206
  • DOI: 10.1002/aenm.201400206

A Rhodanine Flanked Nonfullerene Acceptor for Solution-Processed Organic Photovoltaics
journal, January 2015

  • Holliday, Sarah; Ashraf, Raja Shahid; Nielsen, Christian B.
  • Journal of the American Chemical Society, Vol. 137, Issue 2
  • DOI: 10.1021/ja5110602

Single-junction polymer solar cells with high efficiency and photovoltage
journal, February 2015


Controlling Conformations of Conjugated Polymers and Small Molecules: The Role of Nonbonding Interactions
journal, May 2013

  • Jackson, Nicholas E.; Savoie, Brett M.; Kohlstedt, Kevin L.
  • Journal of the American Chemical Society, Vol. 135, Issue 28
  • DOI: 10.1021/ja403667s

Side Chain Engineering in Solution-Processable Conjugated Polymers
journal, September 2013

  • Mei, Jianguo; Bao, Zhenan
  • Chemistry of Materials, Vol. 26, Issue 1
  • DOI: 10.1021/cm4020805

Solvent-free phenyl-C61-butyric acid methyl ester (PCBM) from clathrates: insights for organic photovoltaics from crystal structures and molecular dynamics
journal, January 2013

  • Casalegno, Mosè; Zanardi, Stefano; Frigerio, Francesco
  • Chemical Communications, Vol. 49, Issue 40
  • DOI: 10.1039/c3cc40863a

Ultrathin and lightweight organic solar cells with high flexibility
journal, January 2012

  • Kaltenbrunner, Martin; White, Matthew S.; Głowacki, Eric D.
  • Nature Communications, Vol. 3, Issue 1
  • DOI: 10.1038/ncomms1772

High-efficiency and air-stable P3HT-based polymer solar cells with a new non-fullerene acceptor
journal, June 2016

  • Holliday, Sarah; Ashraf, Raja Shahid; Wadsworth, Andrew
  • Nature Communications, Vol. 7, Issue 1
  • DOI: 10.1038/ncomms11585

Relationship between crystal packing and high electron mobility in the single crystal of thienyl-substituted methanofullerene
journal, January 2011

  • Choi, Jung Hei; Honda, Tatsuhiko; Seki, Shu
  • Chemical Communications, Vol. 47, Issue 40
  • DOI: 10.1039/c1cc13228h

Regioisomer effects of [70]fullerene mono-adduct acceptors in bulk heterojunction polymer solar cells
journal, January 2017

  • Umeyama, Tomokazu; Miyata, Tetsushi; Jakowetz, Andreas C.
  • Chemical Science, Vol. 8, Issue 1
  • DOI: 10.1039/C6SC02950G

High-efficiency polymer solar cells with small photon energy loss
journal, December 2015

  • Kawashima, Kazuaki; Tamai, Yasunari; Ohkita, Hideo
  • Nature Communications, Vol. 6, Issue 1
  • DOI: 10.1038/ncomms10085

An Electron Acceptor Challenging Fullerenes for Efficient Polymer Solar Cells
journal, January 2015


Molecular Understanding of Organic Solar Cells: The Challenges
journal, November 2009

  • Brédas, Jean-Luc; Norton, Joseph E.; Cornil, Jérôme
  • Accounts of Chemical Research, Vol. 42, Issue 11
  • DOI: 10.1021/ar900099h

Long, Atomically Precise Donor–Acceptor Cove-Edge Nanoribbons as Electron Acceptors
journal, April 2017

  • Sisto, Thomas J.; Zhong, Yu; Zhang, Boyuan
  • Journal of the American Chemical Society, Vol. 139, Issue 16
  • DOI: 10.1021/jacs.6b13093

Polarization Energies in Oligoacene Semiconductor Crystals
journal, September 2008

  • Norton, Joseph E.; Brédas, Jean-Luc
  • Journal of the American Chemical Society, Vol. 130, Issue 37
  • DOI: 10.1021/ja8017797

Evaluation of the External Reorganization Energy of Polyacenes
journal, February 2010

  • McMahon, David P.; Troisi, Alessandro
  • The Journal of Physical Chemistry Letters, Vol. 1, Issue 6
  • DOI: 10.1021/jz1001049

Recent progress in non-fullerene small molecule acceptors in organic solar cells (OSCs)
journal, January 2017

  • Chen, Wangqiao; Zhang, Qichun
  • Journal of Materials Chemistry C, Vol. 5, Issue 6
  • DOI: 10.1039/C6TC05066B

On the Inapplicability of Electron-Hopping Models for the Organic Semiconductor Phenyl-C61-butyric Acid Methyl Ester (PCBM)
journal, March 2013

  • Gajdos, Fruzsina; Oberhofer, Harald; Dupuis, Michel
  • The Journal of Physical Chemistry Letters, Vol. 4, Issue 6
  • DOI: 10.1021/jz400227c

The Power of Nonconventional Phenyl C–H···N Hydrogen Bonds: Supportive Crystal-Packing Force and Dominant Supramolecular Engineering Force
journal, February 2015

  • Bosch, Eric; Bowling, Nathan P.; Darko, Jeffery
  • Crystal Growth & Design, Vol. 15, Issue 4
  • DOI: 10.1021/cg5014076

Correction to “Inapplicability of Electron-Hopping Models for the Organic Semiconductor Phenyl-C61-butyric Acid Methyl Ester (PCBM)”
journal, July 2014

  • Gajdos, Fruzsina; Oberhofer, Harald; Dupuis, Michel
  • The Journal of Physical Chemistry Letters, Vol. 5, Issue 15
  • DOI: 10.1021/jz5014455

Helical Ribbons for Molecular Electronics
journal, May 2014

  • Zhong, Yu; Kumar, Bharat; Oh, Seokjoon
  • Journal of the American Chemical Society, Vol. 136, Issue 22
  • DOI: 10.1021/ja503533y

Organic and Polymeric Semiconductors Enhanced by Noncovalent Conformational Locks
journal, July 2017


Non-Fullerene Electron Acceptors for Use in Organic Solar Cells
journal, October 2015

  • Nielsen, Christian B.; Holliday, Sarah; Chen, Hung-Yang
  • Accounts of Chemical Research, Vol. 48, Issue 11
  • DOI: 10.1021/acs.accounts.5b00199

A Large-Bandgap Conjugated Polymer for Versatile Photovoltaic Applications with High Performance
journal, July 2015


Three-Bladed Rylene Propellers with Three-Dimensional Network Assembly for Organic Electronics
journal, August 2016

  • Meng, Dong; Fu, Huiting; Xiao, Chengyi
  • Journal of the American Chemical Society, Vol. 138, Issue 32
  • DOI: 10.1021/jacs.6b04368

Non-fullerene acceptors for organic solar cells
journal, February 2018


Influence of Molecular Shape on Solid-State Packing in Disordered PC 61 BM and PC 71 BM Fullerenes
journal, September 2014

  • Williams, Monika; Tummala, Naga Rajesh; Aziz, Saadullah G.
  • The Journal of Physical Chemistry Letters, Vol. 5, Issue 19
  • DOI: 10.1021/jz501559q

An approximate method for calculating transfer integrals based on the ZINDO Hamiltonian
journal, January 2007

  • Kirkpatrick, James
  • International Journal of Quantum Chemistry, Vol. 108, Issue 1
  • DOI: 10.1002/qua.21378

C–H ⋯ N mediated hexagonal network in the crystal structure of the 1 : 1 molecular complex 1,3,5-tricyanobenzene–hexamethylbenzene
journal, January 1993

  • Reddy, D. Shekhar; Goud, B. Satish; Panneerselvam, Kaliyamoorthy
  • J. Chem. Soc., Chem. Commun., Issue 8
  • DOI: 10.1039/C39930000663

Charge Transport in Organic Semiconductors
journal, April 2007

  • Coropceanu, Veaceslav; Cornil, Jérôme; da Silva Filho, Demetrio A.
  • Chemical Reviews, Vol. 107, Issue 4
  • DOI: 10.1021/cr050140x

Molecular Optimization Enables over 13% Efficiency in Organic Solar Cells
journal, May 2017

  • Zhao, Wenchao; Li, Sunsun; Yao, Huifeng
  • Journal of the American Chemical Society, Vol. 139, Issue 21
  • DOI: 10.1021/jacs.7b02677

Static and Dynamic Energetic Disorders in the C 60 , PC 61 BM, C 70 , and PC 71 BM Fullerenes
journal, August 2015

  • Tummala, Naga Rajesh; Zheng, Zilong; Aziz, Saadullah G.
  • The Journal of Physical Chemistry Letters, Vol. 6, Issue 18
  • DOI: 10.1021/acs.jpclett.5b01709

Progress and Challenges in Commercialization of Organic Electronics
journal, July 2008

  • Loo, Yueh-Lin; McCulloch, Iain
  • MRS Bulletin, Vol. 33, Issue 07, p. 653-662
  • DOI: 10.1557/mrs2008.149

A map of high-mobility molecular semiconductors
journal, September 2017

  • Fratini, S.; Ciuchi, S.; Mayou, D.
  • Nature Materials, Vol. 16, Issue 10
  • DOI: 10.1038/nmat4970

Design of a New Small‐Molecule Electron Acceptor Enables Efficient Polymer Solar Cells with High Fill Factor
journal, October 2017


An intermediate neglect of differential overlap technique for spectroscopy: Pyrrole and the azines
journal, January 1973

  • Ridley, J.; Zerner, Michael
  • Theoretica Chimica Acta, Vol. 32, Issue 2
  • DOI: 10.1007/BF00528484

Trends in the electronic and geometric structure of non-fullerene based acceptors for organic solar cells
journal, January 2017

  • Kuzmich, Alina; Padula, Daniele; Ma, Haibo
  • Energy & Environmental Science, Vol. 10, Issue 2
  • DOI: 10.1039/C6EE03654F

Theory of space-charge-limited current enhanced by Frenkel effect
journal, February 1970


Recent Advances in Bulk Heterojunction Polymer Solar Cells
journal, August 2015


Dynamic disorder in molecular semiconductors: Charge transport in two dimensions
journal, January 2011

  • Troisi, Alessandro
  • The Journal of Chemical Physics, Vol. 134, Issue 3
  • DOI: 10.1063/1.3524314

Tandem Solar Cells from Accessible Low Band-Gap Polymers Using an Efficient Interconnecting Layer
journal, December 2015

  • Bag, Santanu; Patel, Romesh J.; Bunha, Ajaykumar
  • ACS Applied Materials & Interfaces, Vol. 8, Issue 1
  • DOI: 10.1021/acsami.5b10170

Comparison of different rate constant expressions for the prediction of charge and energy transport in oligoacenes: Prediction of charge and energy transport in oligoacenes using rate constant expressions
journal, July 2016

  • Stehr, V.; Fink, R. F.; Tafipolski, M.
  • Wiley Interdisciplinary Reviews: Computational Molecular Science, Vol. 6, Issue 6
  • DOI: 10.1002/wcms.1273

Unequal Partnership: Asymmetric Roles of Polymeric Donor and Fullerene Acceptor in Generating Free Charge
journal, February 2014

  • Savoie, Brett M.; Rao, Akshay; Bakulin, Artem A.
  • Journal of the American Chemical Society, Vol. 136, Issue 7
  • DOI: 10.1021/ja411859m

The future of organic photovoltaics
journal, January 2015

  • Mazzio, Katherine A.; Luscombe, Christine K.
  • Chemical Society Reviews, Vol. 44, Issue 1
  • DOI: 10.1039/C4CS00227J

Enhancing Indacenodithiophene Acceptor Crystallinity via Substituent Manipulation Increases Organic Solar Cell Efficiency
journal, November 2017


Theoretical Study of the Organic Photovoltaic Electron Acceptor PCBM: Morphology, Electronic Structure, and Charge Localization
journal, July 2010

  • Cheung, David L.; Troisi, Alessandro
  • The Journal of Physical Chemistry C, Vol. 114, Issue 48
  • DOI: 10.1021/jp1049167

New developments in non-fullerene small molecule acceptors for polymer solar cells
journal, January 2017

  • Liang, Ningning; Jiang, Wei; Hou, Jianhui
  • Materials Chemistry Frontiers, Vol. 1, Issue 7
  • DOI: 10.1039/C6QM00247A

Tailorable PC 71 BM Isomers: Using the Most Prevalent Electron Acceptor to Obtain High-Performance Polymer Solar Cells
journal, November 2016

  • Zhan, Xin-Xing; Zhang, Xin; Dai, Si-Min
  • Chemistry - A European Journal, Vol. 22, Issue 52
  • DOI: 10.1002/chem.201604263

Correlation of crystalline and structural properties of C60 thin films grown at various temperature with charge carrier mobility
journal, May 2007

  • Singh, Th. B.; Sariciftci, N. S.; Yang, H.
  • Applied Physics Letters, Vol. 90, Issue 21
  • DOI: 10.1063/1.2743386

Advanced capabilities for materials modelling with Quantum ESPRESSO
journal, October 2017

  • Giannozzi, P.; Andreussi, O.; Brumme, T.
  • Journal of Physics: Condensed Matter, Vol. 29, Issue 46
  • DOI: 10.1088/1361-648X/aa8f79

A High-Efficiency Organic Solar Cell Enabled by the Strong Intramolecular Electron Push-Pull Effect of the Nonfullerene Acceptor
journal, March 2018


    Works referencing / citing this record:

    Perovskite Solar Fibers: Current Status, Issues and Challenges
    journal, October 2019


    Cyclopenta[ b ]thiopyran and cyclopenta[ b ]selenopyran based heteroarenes: electronic communication between S- and/or Se-fused aromatics
    journal, January 2019

    • Qiao, Yanjun; Lu, Yifan; Chen, Weinan
    • Chemical Communications, Vol. 55, Issue 35
    • DOI: 10.1039/c9cc01761e

    Meta-analysis: the molecular organization of non-fullerene acceptors
    journal, January 2020

    • Mondelli, Pierluigi; Boschetto, Gabriele; Horton, Peter N.
    • Materials Horizons
    • DOI: 10.1039/c9mh01439j