skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Preferential Charge Generation at Aggregate Sites in Narrow Band Gap Infrared Photoresponsive Polymer Semiconductors

Abstract

Infrared organic photodetector materials are investigated using transient absorption spectroscopy, demonstrating that ultrafast charge generation assisted by polymer aggregation is essential to compensate for the energy gap law, which dictates that excited state lifetimes decrease as the band gap narrows. Short sub–picosecond singlet exciton lifetimes are measured in a structurally related series of infrared–absorbing copolymers that consist of alternating cyclopentadithiophene electron–rich “push” units and strong electron–deficient “pull” units, including benzothiadiazole, benzoselenadiazole, pyridalselenadiazole, or thiadiazoloquinoxaline. While the ultrafast lifetimes of excitons localized on individual polymer chains suggest that charge carrier generation will be inefficient, high detectivity for polymer:PC71BM infrared photodetectors is measured in the 0.6 < λ < 1.5 µm range. The photophysical processes leading to charge generation are investigated by performing a global analysis on transient absorption data of blended polymer:PC71BM films. In these blends, charge carriers form primarily at polymer aggregate sites on the ultrafast time scale (within our instrument response), leaving quickly decaying single–chain excitons unquenched. Lastly, the results have important implications for the further development of organic infrared optoelectronic devices, where targeting processes such as excited state delocalization over aggregates may be necessary to mitigate losses to ultrafast exciton decay as materials with even lower band gapsmore » are developed.« less

Authors:
 [1]; ORCiD logo [2];  [2];  [3]; ORCiD logo [4];  [4];  [3];  [1]; ORCiD logo [2]; ORCiD logo [5]
  1. Univ. of Washington, Seattle, WA (United States)
  2. Univ. of Southern Mississippi, Hattiesburg, MS (United States)
  3. Univ. of California, Riverside, CA (United States)
  4. Univ. of California San Diego, La Jolla, CA (United States)
  5. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1454810
Alternate Identifier(s):
OSTI ID: 1420339
Report Number(s):
BNL-205769-2018-JAAM
Journal ID: ISSN 2195-1071
Grant/Contract Number:  
SC0012704; SC0016269
Resource Type:
Accepted Manuscript
Journal Name:
Advanced Optical Materials
Additional Journal Information:
Journal Volume: 6; Journal Issue: 7; Journal ID: ISSN 2195-1071
Publisher:
Wiley
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; organic electronics; ultrafast spectroscopy; delocalization; push-pull; bulk heterojunction

Citation Formats

Sulas, Dana B., London, Alexander E., Huang, Lifeng, Xu, Lihua, Wu, Zhenghui, Ng, Tse Nga, Wong, Bryan M., Schlenker, Cody W., Azoulay, Jason D., and Sfeir, Matthew Y. Preferential Charge Generation at Aggregate Sites in Narrow Band Gap Infrared Photoresponsive Polymer Semiconductors. United States: N. p., 2018. Web. doi:10.1002/adom.201701138.
Sulas, Dana B., London, Alexander E., Huang, Lifeng, Xu, Lihua, Wu, Zhenghui, Ng, Tse Nga, Wong, Bryan M., Schlenker, Cody W., Azoulay, Jason D., & Sfeir, Matthew Y. Preferential Charge Generation at Aggregate Sites in Narrow Band Gap Infrared Photoresponsive Polymer Semiconductors. United States. doi:10.1002/adom.201701138.
Sulas, Dana B., London, Alexander E., Huang, Lifeng, Xu, Lihua, Wu, Zhenghui, Ng, Tse Nga, Wong, Bryan M., Schlenker, Cody W., Azoulay, Jason D., and Sfeir, Matthew Y. Tue . "Preferential Charge Generation at Aggregate Sites in Narrow Band Gap Infrared Photoresponsive Polymer Semiconductors". United States. doi:10.1002/adom.201701138. https://www.osti.gov/servlets/purl/1454810.
@article{osti_1454810,
title = {Preferential Charge Generation at Aggregate Sites in Narrow Band Gap Infrared Photoresponsive Polymer Semiconductors},
author = {Sulas, Dana B. and London, Alexander E. and Huang, Lifeng and Xu, Lihua and Wu, Zhenghui and Ng, Tse Nga and Wong, Bryan M. and Schlenker, Cody W. and Azoulay, Jason D. and Sfeir, Matthew Y.},
abstractNote = {Infrared organic photodetector materials are investigated using transient absorption spectroscopy, demonstrating that ultrafast charge generation assisted by polymer aggregation is essential to compensate for the energy gap law, which dictates that excited state lifetimes decrease as the band gap narrows. Short sub–picosecond singlet exciton lifetimes are measured in a structurally related series of infrared–absorbing copolymers that consist of alternating cyclopentadithiophene electron–rich “push” units and strong electron–deficient “pull” units, including benzothiadiazole, benzoselenadiazole, pyridalselenadiazole, or thiadiazoloquinoxaline. While the ultrafast lifetimes of excitons localized on individual polymer chains suggest that charge carrier generation will be inefficient, high detectivity for polymer:PC71BM infrared photodetectors is measured in the 0.6 < λ < 1.5 µm range. The photophysical processes leading to charge generation are investigated by performing a global analysis on transient absorption data of blended polymer:PC71BM films. In these blends, charge carriers form primarily at polymer aggregate sites on the ultrafast time scale (within our instrument response), leaving quickly decaying single–chain excitons unquenched. Lastly, the results have important implications for the further development of organic infrared optoelectronic devices, where targeting processes such as excited state delocalization over aggregates may be necessary to mitigate losses to ultrafast exciton decay as materials with even lower band gaps are developed.},
doi = {10.1002/adom.201701138},
journal = {Advanced Optical Materials},
number = 7,
volume = 6,
place = {United States},
year = {2018},
month = {2}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 5 works
Citation information provided by
Web of Science

Figures / Tables:

Scheme 1 Scheme 1: Photophysical processes following excitation of electron (purple) – hole (teal) pairs by absorption of light energy (hv). Single polymer chains (top) exhibit ultrafast (~ 1 ps) relaxation to the ground state (S0) from singlet excitons (S1), even in blended films with PC71BM acceptor molecules. Aggregates (bottom) show extendedmore » lifetimes in neat films and exhibit ultrafast polaron formation (P+/-, ~ 0.1 ps) in blended films via charge transfer (CT) with PC71BM.« less

Save / Share:

Works referenced in this record:

Solution-Processable Donor-Acceptor Polymers with Modular Electronic Properties and Very Narrow Bandgaps
journal, June 2014

  • Foster, Michael E.; Zhang, Benjamin A.; Murtagh, Dustin
  • Macromolecular Rapid Communications, Vol. 35, Issue 17
  • DOI: 10.1002/marc.201400228

Visualizing excitations at buried heterojunctions in organic semiconductor blends
journal, February 2017

  • Jakowetz, Andreas C.; Böhm, Marcus L.; Sadhanala, Aditya
  • Nature Materials, Vol. 16, Issue 5
  • DOI: 10.1038/nmat4865

Glotaran : A Java -Based Graphical User Interface for the R Package TIMP
journal, January 2012

  • Snellenburg, Joris J.; Laptenok, Sergey P.; Seger, Ralf
  • Journal of Statistical Software, Vol. 49, Issue 3
  • DOI: 10.18637/jss.v049.i03

Low-Bandgap Near-IR Conjugated Polymers/Molecules for Organic Electronics
journal, August 2015


Solution Phase Exciton Diffusion Dynamics of a Charge-Transfer Copolymer PTB7 and a Homopolymer P3HT
journal, December 2014

  • Cho, Sung; Rolczynski, Brian S.; Xu, Tao
  • The Journal of Physical Chemistry B, Vol. 119, Issue 24
  • DOI: 10.1021/jp5111345

The Role of Driving Energy and Delocalized States for Charge Separation in Organic Semiconductors
journal, February 2012


Organic narrowband near-infrared photodetectors based on intermolecular charge-transfer absorption
journal, June 2017

  • Siegmund, Bernhard; Mischok, Andreas; Benduhn, Johannes
  • Nature Communications, Vol. 8, Issue 1
  • DOI: 10.1038/ncomms15421

Interplay Between Side Chain Pattern, Polymer Aggregation, and Charge Carrier Dynamics in PBDTTPD:PCBM Bulk-Heterojunction Solar Cells
journal, January 2015

  • Dyer-Smith, Clare; Howard, Ian A.; Cabanetos, Clément
  • Advanced Energy Materials, Vol. 5, Issue 9
  • DOI: 10.1002/aenm.201401778

Bimolecular Recombination in Organic Photovoltaics
journal, April 2014


Importance of unpaired electrons in organic electronics
journal, August 2014

  • Yuen, Jonathan D.; Wang, Mingfeng; Fan, Jian
  • Journal of Polymer Science Part A: Polymer Chemistry, Vol. 53, Issue 2
  • DOI: 10.1002/pola.27321

The fate of electron–hole pairs in polymer:fullerene blends for organic photovoltaics
journal, September 2016

  • Causa', Martina; De Jonghe-Risse, Jelissa; Scarongella, Mariateresa
  • Nature Communications, Vol. 7, Issue 1
  • DOI: 10.1038/ncomms12556

High-Detectivity Polymer Photodetectors with Spectral Response from 300 nm to 1450 nm
journal, August 2009


Small-Bandgap Semiconducting Polymers with High Near-Infrared Photoresponse
journal, August 2014

  • Hendriks, Koen H.; Li, Weiwei; Wienk, Martijn M.
  • Journal of the American Chemical Society, Vol. 136, Issue 34
  • DOI: 10.1021/ja506265h

Integrating theory, synthesis, spectroscopy and device efficiency to design and characterize donor materials for organic photovoltaics: a case study including 12 donors
journal, January 2015

  • Oosterhout, S. D.; Kopidakis, N.; Owczarczyk, Z. R.
  • Journal of Materials Chemistry A, Vol. 3, Issue 18
  • DOI: 10.1039/C5TA01153A

A general relationship between disorder, aggregation and charge transport in conjugated polymers
journal, August 2013

  • Noriega, Rodrigo; Rivnay, Jonathan; Vandewal, Koen
  • Nature Materials, Vol. 12, Issue 11
  • DOI: 10.1038/nmat3722

Effects of Exciton Polarity in Charge-Transfer Polymer/PCBM Bulk Heterojunction Films
journal, May 2014

  • Rolczynski, Brian S.; Szarko, Jodi M.; Son, Hae Jung
  • The Journal of Physical Chemistry Letters, Vol. 5, Issue 11
  • DOI: 10.1021/jz5005957

Approaching disorder-free transport in high-mobility conjugated polymers
journal, November 2014

  • Venkateshvaran, Deepak; Nikolka, Mark; Sadhanala, Aditya
  • Nature, Vol. 515, Issue 7527
  • DOI: 10.1038/nature13854

Temperature-Dependent Detectivity of Near-Infrared Organic Bulk Heterojunction Photodiodes
journal, January 2017

  • Wu, Zhenghui; Yao, Weichuan; London, Alexander E.
  • ACS Applied Materials & Interfaces, Vol. 9, Issue 2
  • DOI: 10.1021/acsami.6b12162

The energy gap law for radiationless transitions in large molecules
journal, February 1970


Donor–acceptor polymers with tunable infrared photoresponse
journal, January 2017

  • London, Alexander E.; Huang, Lifeng; Zhang, Benjamin A.
  • Polymer Chemistry, Vol. 8, Issue 19
  • DOI: 10.1039/C7PY00241F

Effect of chiral 2-ethylhexyl side chains on chiroptical properties of the narrow bandgap conjugated polymers PCPDTBT and PCDTPT
journal, January 2016

  • Fronk, Stephanie L.; Wang, Ming; Ford, Michael
  • Chemical Science, Vol. 7, Issue 8
  • DOI: 10.1039/C6SC00908E

An Optimal Driving Force for Converting Excitons into Free Carriers in Excitonic Solar Cells
journal, April 2012

  • Coffey, David C.; Larson, Bryon W.; Hains, Alexander W.
  • The Journal of Physical Chemistry C, Vol. 116, Issue 16
  • DOI: 10.1021/jp302275z

The Energy Gap Law for Triplet States in Pt-Containing Conjugated Polymers and Monomers
journal, September 2001

  • Wilson, Joanne S.; Chawdhury, Nazia; Al-Mandhary, Muna R. A.
  • Journal of the American Chemical Society, Vol. 123, Issue 38
  • DOI: 10.1021/ja010986s

Exciton delocalization incorporated drift-diffusion model for bulk-heterojunction organic solar cells
journal, December 2016

  • Wang, Zi Shuai; Sha, Wei E. I.; Choy, Wallace C. H.
  • Journal of Applied Physics, Vol. 120, Issue 21
  • DOI: 10.1063/1.4970958

Quantitative Bimolecular Recombination in Organic Photovoltaics through Triplet Exciton Formation
journal, February 2014

  • Chow, Philip C. Y.; Gélinas, Simon; Rao, Akshay
  • Journal of the American Chemical Society, Vol. 136, Issue 9
  • DOI: 10.1021/ja410092n

Mesoscopic quantum emitters from deterministic aggregates of conjugated polymers
journal, September 2015

  • Stangl, Thomas; Wilhelm, Philipp; Remmerssen, Klaas
  • Proceedings of the National Academy of Sciences, Vol. 112, Issue 41
  • DOI: 10.1073/pnas.1512582112

Fast Singlet Exciton Decay in Push–Pull Molecules Containing Oxidized Thiophenes
journal, December 2014

  • Busby, Erik; Xia, Jianlong; Low, Jonathan Z.
  • The Journal of Physical Chemistry B, Vol. 119, Issue 24
  • DOI: 10.1021/jp511704r

High-Hole-Mobility Field-Effect Transistors Based on Co- Benzobisthiadiazole-Quaterthiophene
journal, September 2012


On the relation between radiative and nonradiative transitions in molecules
journal, April 1971


Nonequilibrium Charge Dynamics in Organic Solar Cells
journal, March 2014

  • Howard, Ian A.; Etzold, Fabian; Laquai, Frédéric
  • Advanced Energy Materials, Vol. 4, Issue 9
  • DOI: 10.1002/aenm.201301743

Aggregation and morphology control enables multiple cases of high-efficiency polymer solar cells
journal, November 2014

  • Liu, Yuhang; Zhao, Jingbo; Li, Zhengke
  • Nature Communications, Vol. 5, Issue 1
  • DOI: 10.1038/ncomms6293

Ultrafast Exciton Dissociation Followed by Nongeminate Charge Recombination in PCDTBT:PCBM Photovoltaic Blends
journal, June 2011

  • Etzold, Fabian; Howard, Ian A.; Mauer, Ralf
  • Journal of the American Chemical Society, Vol. 133, Issue 24
  • DOI: 10.1021/ja201837e

Thiadizoloquinoxaline-Based Low-Bandgap Conjugated Polymers as Ambipolar Semiconductors for Organic Field Effect Transistors
journal, October 2014

  • An, Cunbin; Li, Mengmeng; Marszalek, Tomasz
  • Chemistry of Materials, Vol. 26, Issue 20
  • DOI: 10.1021/cm502563t

Ultrafast Singlet Fission in a Push–Pull Low-Bandgap Polymer Film
journal, December 2015

  • Kasai, Yukitomo; Tamai, Yasunari; Ohkita, Hideo
  • Journal of the American Chemical Society, Vol. 137, Issue 51
  • DOI: 10.1021/jacs.5b09361

Charge Photogeneration in Neat Conjugated Polymers
journal, September 2013

  • Reid, Obadiah G.; Pensack, Ryan D.; Song, Yin
  • Chemistry of Materials, Vol. 26, Issue 1
  • DOI: 10.1021/cm4027144

Effect of Systematically Tuning Conjugated Donor Polymer Lowest Unoccupied Molecular Orbital Levels via Cyano Substitution on Organic Photovoltaic Device Performance
journal, July 2016


Polymer aggregation control in polymer–fullerene bulk heterojunctions adapted from solution
journal, January 2015

  • Kästner, Christian; Egbe, Daniel A. M.; Hoppe, Harald
  • Journal of Materials Chemistry A, Vol. 3, Issue 1
  • DOI: 10.1039/C4TA04736B

High-Performance Ambipolar Transistors and Inverters from an Ultralow Bandgap Polymer
journal, March 2012

  • Fan, Jian; Yuen, Jonathan D.; Wang, Mingfeng
  • Advanced Materials, Vol. 24, Issue 16
  • DOI: 10.1002/adma.201103836

On the Energetic Dependence of Charge Separation in Low-Band-Gap Polymer/Fullerene Blends
journal, October 2012

  • Dimitrov, Stoichko D.; Bakulin, Artem A.; Nielsen, Christian B.
  • Journal of the American Chemical Society, Vol. 134, Issue 44
  • DOI: 10.1021/ja308177d

Radiationless Transitions in Polyatomic Molecules. I. Calculation of Franck—Condon Factors
journal, January 1967

  • Siebrand, W.
  • The Journal of Chemical Physics, Vol. 46, Issue 2
  • DOI: 10.1063/1.1840685

Electronic Excitation Transfer and Relaxation
journal, March 1963

  • Robinson, G. W.; Frosch, R. P.
  • The Journal of Chemical Physics, Vol. 38, Issue 5
  • DOI: 10.1063/1.1733823

A design strategy for intramolecular singlet fission mediated by charge-transfer states in donor–acceptor organic materials
journal, January 2015

  • Busby, Erik; Xia, Jianlong; Wu, Qin
  • Nature Materials, Vol. 14, Issue 4
  • DOI: 10.1038/nmat4175

Photoinduced Charge Generation in a Molecular Bulk Heterojunction Material
journal, November 2012

  • Kaake, Loren G.; Jasieniak, Jacek J.; Bakus, Ronald C.
  • Journal of the American Chemical Society, Vol. 134, Issue 48
  • DOI: 10.1021/ja308949m

Exciton Diffusion in Conjugated Polymers: From Fundamental Understanding to Improvement in Photovoltaic Conversion Efficiency
journal, August 2015

  • Tamai, Yasunari; Ohkita, Hideo; Benten, Hiroaki
  • The Journal of Physical Chemistry Letters, Vol. 6, Issue 17
  • DOI: 10.1021/acs.jpclett.5b01147

25th Anniversary Article: Recent Advances in n-Type and Ambipolar Organic Field-Effect Transistors
journal, August 2013


What Controls the Rate of Ultrafast Charge Transfer and Charge Separation Efficiency in Organic Photovoltaic Blends
journal, September 2016

  • Jakowetz, Andreas C.; Böhm, Marcus L.; Zhang, Jiangbin
  • Journal of the American Chemical Society, Vol. 138, Issue 36
  • DOI: 10.1021/jacs.6b05131

Infrared detectors: an overview
journal, June 2002


Hot exciton dissociation in polymer solar cells
journal, December 2012

  • Grancini, G.; Maiuri, M.; Fazzi, D.
  • Nature Materials, Vol. 12, Issue 1
  • DOI: 10.1038/nmat3502

Very Low Band Gap Thiadiazoloquinoxaline Donor–Acceptor Polymers as Multi-tool Conjugated Polymers
journal, January 2014

  • Steckler, Timothy T.; Henriksson, Patrik; Mollinger, Sonya
  • Journal of the American Chemical Society, Vol. 136, Issue 4
  • DOI: 10.1021/ja410527n

Tailored exciton diffusion in organic photovoltaic cells for enhanced power conversion efficiency
journal, November 2012

  • Menke, S. Matthew; Luhman, Wade A.; Holmes, Russell J.
  • Nature Materials, Vol. 12, Issue 2
  • DOI: 10.1038/nmat3467

Efficiency enhancement in low-bandgap polymer solar cells by processing with alkane dithiols
journal, May 2007

  • Peet, J.; Kim, J. Y.; Coates, N. E.
  • Nature Materials, Vol. 6, Issue 7, p. 497-500
  • DOI: 10.1038/nmat1928

“Hot or cold”: how do charge transfer states at the donor–acceptor interface of an organic solar cell dissociate?
journal, January 2015

  • Bässler, Heinz; Köhler, Anna
  • Physical Chemistry Chemical Physics, Vol. 17, Issue 43
  • DOI: 10.1039/C5CP04110D

Revealing structure formation in PCPDTBT by optical spectroscopy
journal, July 2015

  • Scharsich, Christina; Fischer, Florian S. U.; Wilma, Kevin
  • Journal of Polymer Science Part B: Polymer Physics, Vol. 53, Issue 20
  • DOI: 10.1002/polb.23780

Benzotrithiophene polymers with tuneable bandgap for photovoltaic applications
journal, January 2014

  • Bian, Linyin; Miao, Jingsheng; Hai, Jiefeng
  • RSC Adv., Vol. 4, Issue 96
  • DOI: 10.1039/C4RA07644C

Intermolecular Interactions Determine Exciton Lifetimes in Neat Films and Solid State Solutions of Metal-Free Phthalocyanine
journal, November 2015

  • Caplins, Benjamin W.; Mullenbach, Tyler K.; Holmes, Russell J.
  • The Journal of Physical Chemistry C, Vol. 119, Issue 49
  • DOI: 10.1021/acs.jpcc.5b09817

Trap-Limited Exciton Diffusion in Organic Semiconductors
journal, December 2013

  • Mikhnenko, Oleksandr V.; Kuik, Martijn; Lin, Jason
  • Advanced Materials, Vol. 26, Issue 12
  • DOI: 10.1002/adma.201304162

Strong acceptors in donor–acceptor polymers for high performance thin film transistors
journal, January 2013

  • Yuen, Jonathan D.; Wudl, Fred
  • Energy & Environmental Science, Vol. 6, Issue 2
  • DOI: 10.1039/c2ee23505f

Quantifying the Relationship between the Maximum Achievable Voltage and Current Levels in Low-Bandgap Polymer Photovoltaics
journal, November 2013

  • Rodovsky, Deanna B.; Peet, Jeff; Shao, Nan
  • The Journal of Physical Chemistry C, Vol. 117, Issue 49
  • DOI: 10.1021/jp410234u

Ultrafast Intramolecular Exciton Splitting Dynamics in Isolated Low-Band-Gap Polymers and Their Implications in Photovoltaic Materials Design
journal, February 2012

  • Rolczynski, Brian S.; Szarko, Jodi M.; Son, Hae Jung
  • Journal of the American Chemical Society, Vol. 134, Issue 9
  • DOI: 10.1021/ja209003y

Atomistic Band Gap Engineering in Donor–Acceptor Polymers
journal, December 2011

  • Gibson, Gregory L.; McCormick, Theresa M.; Seferos, Dwight S.
  • Journal of the American Chemical Society, Vol. 134, Issue 1
  • DOI: 10.1021/ja208917m

Ultrafast electron and hole transfer in bulk heterojunctions of low-bandgap polymers
journal, January 2016

  • Kozlov, Oleg V.; Pavelyev, Vlad G.; de Gier, Hilde D.
  • Organic Photonics and Photovoltaics, Vol. 4, Issue 1
  • DOI: 10.1515/oph-2016-0003

Exciton Localization in Extended π-Electron Systems: Comparison of Linear and Cyclic Structures
journal, July 2015

  • Thiessen, Alexander; Würsch, Dominik; Jester, Stefan-S.
  • The Journal of Physical Chemistry B, Vol. 119, Issue 30
  • DOI: 10.1021/acs.jpcb.5b02091

Singlet Exciton Lifetimes in Conjugated Polymer Films for Organic Solar Cells
journal, January 2016

  • Dimitrov, Stoichko; Schroeder, Bob; Nielsen, Christian
  • Polymers, Vol. 8, Issue 1
  • DOI: 10.3390/polym8010014

    Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.