Peculiarity of two thermodynamically-stable morphologies and their impact on the efficiency of small molecule bulk heterojunction solar cells
Abstract
Structural characteristics of the active layers in organic photovoltaic (OPV) devices play a critical role in charge generation, separation and transport. Here we report on morphology and structural control of p-DTS(FBTTh2)2:PC71BM films by means of thermal annealing and 1,8-diiodooctane (DIO) solvent additive processing, and correlate it to the device performance. By combining surface imaging with nanoscale depth-sensitive neutron reflectometry (NR) and X-ray diffraction, three-dimensional morphologies of the films are reconstituted with information extending length scales from nanometers to microns. DIO promotes the formation of a well-mixed donor-acceptor vertical phase morphology with a large population of small p-DTS(FBTTh2)2 nanocrystals arranged in an elongated domain network of the film, thereby enhancing the device performance. In contrast, films without DIO exhibit three-sublayer vertical phase morphology with phase separation in agglomerated domains. Our findings are supported by thermodynamic description based on the Flory-Huggins theory with quantitative evaluation of pairwise interaction parameters that explain the morphological changes resulting from thermal and solvent treatments. Our study reveals that vertical phase morphology of small-molecule based OPVs is significantly different from polymer-based systems. In conclusion, the significant enhancement of morphology and information obtained from theoretical modeling may aid in developing an optimized morphology to enhance device performance formore »
- Authors:
-
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Univ. of Tennessee, Knoxville, TN (United States)
- UNSW Australia, Sydney, NSW (Australia)
- Publication Date:
- Research Org.:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
- Sponsoring Org.:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- OSTI Identifier:
- 1259703
- Alternate Identifier(s):
- OSTI ID: 1333656
- Grant/Contract Number:
- AC05-00OR22725
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Scientific Reports
- Additional Journal Information:
- Journal Volume: 5; Journal ID: ISSN 2045-2322
- Publisher:
- Nature Publishing Group
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 14 SOLAR ENERGY; nanoscale materials; solar cells; 36 MATERIALS SCIENCE
Citation Formats
Herath, Nuradhika, Das, Sanjib, Keum, Jong K., Zhu, Jiahua, Kumar, Rajeev, Ivanov, Ilia N., Sumpter, Bobby G., Browning, James F., Xiao, Kai, Gu, Gong, Joshi, Pooran, Smith, Sean, and Lauter, Valeria. Peculiarity of two thermodynamically-stable morphologies and their impact on the efficiency of small molecule bulk heterojunction solar cells. United States: N. p., 2015.
Web. doi:10.1038/srep13407.
Herath, Nuradhika, Das, Sanjib, Keum, Jong K., Zhu, Jiahua, Kumar, Rajeev, Ivanov, Ilia N., Sumpter, Bobby G., Browning, James F., Xiao, Kai, Gu, Gong, Joshi, Pooran, Smith, Sean, & Lauter, Valeria. Peculiarity of two thermodynamically-stable morphologies and their impact on the efficiency of small molecule bulk heterojunction solar cells. United States. https://doi.org/10.1038/srep13407
Herath, Nuradhika, Das, Sanjib, Keum, Jong K., Zhu, Jiahua, Kumar, Rajeev, Ivanov, Ilia N., Sumpter, Bobby G., Browning, James F., Xiao, Kai, Gu, Gong, Joshi, Pooran, Smith, Sean, and Lauter, Valeria. Fri .
"Peculiarity of two thermodynamically-stable morphologies and their impact on the efficiency of small molecule bulk heterojunction solar cells". United States. https://doi.org/10.1038/srep13407. https://www.osti.gov/servlets/purl/1259703.
@article{osti_1259703,
title = {Peculiarity of two thermodynamically-stable morphologies and their impact on the efficiency of small molecule bulk heterojunction solar cells},
author = {Herath, Nuradhika and Das, Sanjib and Keum, Jong K. and Zhu, Jiahua and Kumar, Rajeev and Ivanov, Ilia N. and Sumpter, Bobby G. and Browning, James F. and Xiao, Kai and Gu, Gong and Joshi, Pooran and Smith, Sean and Lauter, Valeria},
abstractNote = {Structural characteristics of the active layers in organic photovoltaic (OPV) devices play a critical role in charge generation, separation and transport. Here we report on morphology and structural control of p-DTS(FBTTh2)2:PC71BM films by means of thermal annealing and 1,8-diiodooctane (DIO) solvent additive processing, and correlate it to the device performance. By combining surface imaging with nanoscale depth-sensitive neutron reflectometry (NR) and X-ray diffraction, three-dimensional morphologies of the films are reconstituted with information extending length scales from nanometers to microns. DIO promotes the formation of a well-mixed donor-acceptor vertical phase morphology with a large population of small p-DTS(FBTTh2)2 nanocrystals arranged in an elongated domain network of the film, thereby enhancing the device performance. In contrast, films without DIO exhibit three-sublayer vertical phase morphology with phase separation in agglomerated domains. Our findings are supported by thermodynamic description based on the Flory-Huggins theory with quantitative evaluation of pairwise interaction parameters that explain the morphological changes resulting from thermal and solvent treatments. Our study reveals that vertical phase morphology of small-molecule based OPVs is significantly different from polymer-based systems. In conclusion, the significant enhancement of morphology and information obtained from theoretical modeling may aid in developing an optimized morphology to enhance device performance for OPVs.},
doi = {10.1038/srep13407},
journal = {Scientific Reports},
number = ,
volume = 5,
place = {United States},
year = {Fri Aug 28 00:00:00 EDT 2015},
month = {Fri Aug 28 00:00:00 EDT 2015}
}
Web of Science
Works referenced in this record:
Polymer Photovoltaic Cells: Enhanced Efficiencies via a Network of Internal Donor-Acceptor Heterojunctions
journal, December 1995
- Yu, G.; Gao, J.; Hummelen, J. C.
- Science, Vol. 270, Issue 5243, p. 1789-1791
Charge Transport in Organic Semiconductors
journal, April 2007
- Coropceanu, Veaceslav; Cornil, Jérôme; da Silva Filho, Demetrio A.
- Chemical Reviews, Vol. 107, Issue 4
Polymer-Fullerene Bulk-Heterojunction Solar Cells
journal, August 2010
- Brabec, Christoph J.; Gowrisanker, Srinivas; Halls, Jonathan J. M.
- Advanced Materials, Vol. 22, Issue 34
Thermally Stable, Efficient Polymer Solar Cells with Nanoscale Control of the Interpenetrating Network Morphology
journal, October 2005
- Ma, W.; Yang, C.; Gong, X.
- Advanced Functional Materials, Vol. 15, Issue 10, p. 1617-1622
“Plastic” Solar Cells: Self-Assembly of Bulk Heterojunction Nanomaterials by Spontaneous Phase Separation
journal, November 2009
- Peet, Jeffrey; Heeger, Alan J.; Bazan, Guillermo C.
- Accounts of Chemical Research, Vol. 42, Issue 11
Roles of thermally-induced vertical phase segregation and crystallization on the photovoltaic performance of bulk heterojunction inverted polymer solar cells
journal, January 2011
- Cheun, Hyeunseok; Berrigan, John D.; Zhou, Yinhua
- Energy & Environmental Science, Vol. 4, Issue 9
Annealing effects on the photovoltaic performance of all-conjugated poly(3-alkylthiophene) diblock copolymer-based bulk heterojunction solar cells
journal, January 2011
- He, Ming; Han, Wei; Ge, Jing
- Nanoscale, Vol. 3, Issue 8
Understanding the Role of Thermal Processing in High Performance Solution Processed Small Molecule Bulk Heterojunction Solar Cells
journal, October 2012
- Leong, Wei Lin; Welch, Gregory C.; Seifter, Jason
- Advanced Energy Materials, Vol. 3, Issue 3
Morphology of polymer-based bulk heterojunction films for organic photovoltaics
journal, January 2011
- Ruderer, Matthias A.; Müller-Buschbaum, Peter
- Soft Matter, Vol. 7, Issue 12
Film Morphology of High Efficiency Solution-Processed Small-Molecule Solar Cells
journal, May 2013
- Love, John A.; Proctor, Christopher M.; Liu, Jianhua
- Advanced Functional Materials, Vol. 23, Issue 40
Solvent Additive Effects on Small Molecule Crystallization in Bulk Heterojunction Solar Cells Probed During Spin Casting
journal, September 2013
- Perez, Louis A.; Chou, Kang Wei; Love, John A.
- Advanced Materials, Vol. 25, Issue 44
Additives for morphology control in high-efficiency organic solar cells
journal, September 2013
- Liao, Hsueh-Chung; Ho, Chun-Chih; Chang, Chun-Yu
- Materials Today, Vol. 16, Issue 9
Toward High-Performance Polymer Solar Cells: The Importance of Morphology Control
journal, March 2007
- Yang, Xiaoniu; Loos, Joachim
- Macromolecules, Vol. 40, Issue 5, p. 1353-1362
Drastic Control of Texture in a High Performance n-Type Polymeric Semiconductor and Implications for Charge Transport
journal, July 2011
- Rivnay, Jonathan; Steyrleuthner, Robert; Jimison, Leslie H.
- Macromolecules, Vol. 44, Issue 13
Exciton diffusion length in narrow bandgap polymers
journal, January 2012
- Mikhnenko, Oleksandr V.; Azimi, Hamed; Scharber, Markus
- Energy & Environmental Science, Vol. 5, Issue 5
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
Fluorine Substituted Conjugated Polymer of Medium Band Gap Yields 7% Efficiency in Polymer−Fullerene Solar Cells
journal, March 2011
- Price, Samuel C.; Stuart, Andrew C.; Yang, Liqiang
- Journal of the American Chemical Society, Vol. 133, Issue 12
Small Molecule Solution-Processed Bulk Heterojunction Solar Cells †
journal, February 2011
- Walker, Bright; Kim, Chunki; Nguyen, Thuc-Quyen
- Chemistry of Materials, Vol. 23, Issue 3
Small Molecule Organic Semiconductors on the Move: Promises for Future Solar Energy Technology
journal, February 2012
- Mishra, Amaresh; Bäuerle, Peter
- Angewandte Chemie International Edition, Vol. 51, Issue 9
Solution-processed small-molecule solar cells with 6.7% efficiency
journal, November 2011
- Sun, Yanming; Welch, Gregory C.; Leong, Wei Lin
- Nature Materials, Vol. 11, Issue 1, p. 44-48
Small Molecules Based on Benzo[1,2-b:4,5-b′]dithiophene Unit for High-Performance Solution-Processed Organic Solar Cells
journal, September 2012
- Zhou, Jiaoyan; Wan, Xiangjian; Liu, Yongsheng
- Journal of the American Chemical Society, Vol. 134, Issue 39
Donor-acceptor small molecule with coplanar and rigid π-bridge for efficient organic solar cells
journal, February 2013
- Chi, Liang-Chen; Chen, Hsiao-Fan; Hung, Wen-Yi
- Solar Energy Materials and Solar Cells, Vol. 109
Efficient small molecule bulk heterojunction solar cells with high fill factors via introduction of π-stacking moieties as end group
journal, January 2013
- He, Guangrui; Li, Zhi; Wan, Xiangjian
- J. Mater. Chem. A, Vol. 1, Issue 5
Small molecule semiconductors for high-efficiency organic photovoltaics
journal, January 2012
- Lin, Yuze; Li, Yongfang; Zhan, Xiaowei
- Chemical Society Reviews, Vol. 41, Issue 11
Unambiguous determination of molecular packing in crystalline donor domains of small molecule solution processed solar cell devices using routine X-ray diffraction techniques
journal, January 2014
- Viterisi, Aurélien; Montcada, Núria F.; Kumar, Challuri Vijay
- Journal of Materials Chemistry A, Vol. 2, Issue 10
An All-Small-Molecule Organic Solar Cell with High Efficiency Nonfullerene Acceptor
journal, February 2015
- Kwon, Oh Kyu; Park, Jung-Hwa; Kim, Dong Won
- Advanced Materials, Vol. 27, Issue 11
Intensity Dependence of Current–Voltage Characteristics and Recombination in High-Efficiency Solution-Processed Small-Molecule Solar Cells
journal, April 2013
- Kyaw, Aung Ko Ko; Wang, Dong Hwan; Gupta, Vinay
- ACS Nano, Vol. 7, Issue 5
Solution-Processed and High-Performance Organic Solar Cells Using Small Molecules with a Benzodithiophene Unit
journal, May 2013
- Zhou, Jiaoyan; Zuo, Yi; Wan, Xiangjian
- Journal of the American Chemical Society, Vol. 135, Issue 23
Importance of Domain Purity and Molecular Packing in Efficient Solution-Processed Small-Molecule Solar Cells
journal, December 2014
- Mukherjee, Subhrangsu; Proctor, Christopher M.; Tumbleston, John R.
- Advanced Materials, Vol. 27, Issue 6
Quantification of Nano- and Mesoscale Phase Separation and Relation to Donor and Acceptor Quantum Efficiency, J sc , and FF in Polymer:Fullerene Solar Cells
journal, March 2014
- Ma, Wei; Tumbleston, John R.; Ye, Long
- Advanced Materials, Vol. 26, Issue 25
Characterization of the Polymer Energy Landscape in Polymer:Fullerene Bulk Heterojunctions with Pure and Mixed Phases
journal, August 2014
- Sweetnam, Sean; Graham, Kenneth R.; Ngongang Ndjawa, Guy O.
- Journal of the American Chemical Society, Vol. 136, Issue 40
High mobility n-channel organic field-effect transistors based on soluble C60 and C70 fullerene derivatives
journal, July 2008
- Wöbkenberg, Paul H.; Bradley, Donal D. C.; Kronholm, David
- Synthetic Metals, Vol. 158, Issue 11
Phase-sensitive neutron reflectometry measurements applied in the study of photovoltaic films
journal, August 2010
- Kiel, J. W.; Mackay, M. E.; Kirby, B. J.
- The Journal of Chemical Physics, Vol. 133, Issue 7
The Nanoscale Morphology of a PCDTBT:PCBM Photovoltaic Blend
journal, April 2011
- Staniec, Paul A.; Parnell, Andrew J.; Dunbar, Alan D. F.
- Advanced Energy Materials, Vol. 1, Issue 4
PS-b-P3HT Copolymers as P3HT/PCBM Interfacial Compatibilizers for High Efficiency Photovoltaics
journal, November 2011
- Sun, Zhenzhong; Xiao, Kai; Keum, Jong Kahk
- Advanced Materials, Vol. 23, Issue 46
Morphological origin for the stratification of P3HT:PCBM blend film studied by neutron reflectometry
journal, November 2013
- Keum, Jong Kahk; Browning, James F.; Xiao, Kai
- Applied Physics Letters, Vol. 103, Issue 22
The isotopic effects of deuteration on optoelectronic properties of conducting polymers
journal, January 2014
- Shao, Ming; Keum, Jong; Chen, Jihua
- Nature Communications, Vol. 5, Issue 1
Nanoparticle concentration profile in polymer-based solar cells
journal, January 2010
- Kiel, Jonathan W.; Kirby, Brian J.; Majkrzak, Charles F.
- Soft Matter, Vol. 6, Issue 3, p. 641-646
Polymer-Fullerene Miscibility: A Metric for Screening New Materials for High-Performance Organic Solar Cells
journal, September 2012
- Treat, Neil D.; Varotto, Alessandro; Takacs, Christopher J.
- Journal of the American Chemical Society, Vol. 134, Issue 38
Surface Studies of Solids by Total Reflection of X-Rays
journal, July 1954
- Parratt, L. G.
- Physical Review, Vol. 95, Issue 2
The Effect of additive on performance and shelf-stability of HSX-1/PCBM photovoltaic devices
journal, September 2011
- Li, Weiwei; Zhou, Yi; Viktor Andersson, B.
- Organic Electronics, Vol. 12, Issue 9
The Spectral Signatures of Frenkel Polarons in H- and J-Aggregates
journal, March 2010
- Spano, Frank C.
- Accounts of Chemical Research, Vol. 43, Issue 3
Reciprocity relation between photovoltaic quantum efficiency and electroluminescent emission of solar cells
journal, August 2007
- Rau, Uwe
- Physical Review B, Vol. 76, Issue 8
New insights into the dynamics and morphology of P3HT:PCBM active layers in bulk heterojunctions
journal, January 2013
- Carrillo, Jan-Michael Y.; Kumar, Rajeev; Goswami, Monojoy
- Physical Chemistry Chemical Physics, Vol. 15, Issue 41
Film Morphology of High Efficiency Solution-Processed Small-Molecule Solar Cells
journal, May 2013
- Love, John A.; Proctor, Christopher M.; Liu, Jianhua
- Advanced Functional Materials, Vol. 23, Issue 40
Polymer-Fullerene Bulk-Heterojunction Solar Cells
journal, August 2010
- Brabec, Christoph J.; Gowrisanker, Srinivas; Halls, Jonathan J. M.
- Advanced Materials, Vol. 22, Issue 34
Quantification of Nano- and Mesoscale Phase Separation and Relation to Donor and Acceptor Quantum Efficiency, J sc , and FF in Polymer:Fullerene Solar Cells
journal, March 2014
- Ma, Wei; Tumbleston, John R.; Ye, Long
- Advanced Materials, Vol. 26, Issue 25
Importance of Domain Purity and Molecular Packing in Efficient Solution-Processed Small-Molecule Solar Cells
journal, December 2014
- Mukherjee, Subhrangsu; Proctor, Christopher M.; Tumbleston, John R.
- Advanced Materials, Vol. 27, Issue 6
The Nanoscale Morphology of a PCDTBT:PCBM Photovoltaic Blend
journal, April 2011
- Staniec, Paul A.; Parnell, Andrew J.; Dunbar, Alan D. F.
- Advanced Energy Materials, Vol. 1, Issue 4
Understanding the Role of Thermal Processing in High Performance Solution Processed Small Molecule Bulk Heterojunction Solar Cells
journal, October 2012
- Leong, Wei Lin; Welch, Gregory C.; Seifter, Jason
- Advanced Energy Materials, Vol. 3, Issue 3
Small Molecule Organic Semiconductors on the Move: Promises for Future Solar Energy Technology
journal, February 2012
- Mishra, Amaresh; Bäuerle, Peter
- Angewandte Chemie International Edition, Vol. 51, Issue 9
Charge Transport in Organic Semiconductors
journal, July 2007
- Coropceanu, Veaceslav; Cornil, Jerome; da Silva Filho, Demetrio A.
- ChemInform, Vol. 38, Issue 29
Additives for morphology control in high-efficiency organic solar cells
journal, September 2013
- Liao, Hsueh-Chung; Ho, Chun-Chih; Chang, Chun-Yu
- Materials Today, Vol. 16, Issue 9
“Plastic” Solar Cells: Self-Assembly of Bulk Heterojunction Nanomaterials by Spontaneous Phase Separation
journal, November 2009
- Peet, Jeffrey; Heeger, Alan J.; Bazan, Guillermo C.
- Accounts of Chemical Research, Vol. 42, Issue 11
Small Molecule Solution-Processed Bulk Heterojunction Solar Cells †
journal, February 2011
- Walker, Bright; Kim, Chunki; Nguyen, Thuc-Quyen
- Chemistry of Materials, Vol. 23, Issue 3
Fluorine Substituted Conjugated Polymer of Medium Band Gap Yields 7% Efficiency in Polymer−Fullerene Solar Cells
journal, March 2011
- Price, Samuel C.; Stuart, Andrew C.; Yang, Liqiang
- Journal of the American Chemical Society, Vol. 133, Issue 12
Polymer-Fullerene Miscibility: A Metric for Screening New Materials for High-Performance Organic Solar Cells
journal, September 2012
- Treat, Neil D.; Varotto, Alessandro; Takacs, Christopher J.
- Journal of the American Chemical Society, Vol. 134, Issue 38
Small Molecules Based on Benzo[1,2-b:4,5-b′]dithiophene Unit for High-Performance Solution-Processed Organic Solar Cells
journal, September 2012
- Zhou, Jiaoyan; Wan, Xiangjian; Liu, Yongsheng
- Journal of the American Chemical Society, Vol. 134, Issue 39
Solution-Processed and High-Performance Organic Solar Cells Using Small Molecules with a Benzodithiophene Unit
journal, May 2013
- Zhou, Jiaoyan; Zuo, Yi; Wan, Xiangjian
- Journal of the American Chemical Society, Vol. 135, Issue 23
Characterization of the Polymer Energy Landscape in Polymer:Fullerene Bulk Heterojunctions with Pure and Mixed Phases
journal, August 2014
- Sweetnam, Sean; Graham, Kenneth R.; Ngongang Ndjawa, Guy O.
- Journal of the American Chemical Society, Vol. 136, Issue 40
Toward High-Performance Polymer Solar Cells: The Importance of Morphology Control
journal, March 2007
- Yang, Xiaoniu; Loos, Joachim
- Macromolecules, Vol. 40, Issue 5, p. 1353-1362
Drastic Control of Texture in a High Performance n-Type Polymeric Semiconductor and Implications for Charge Transport
journal, July 2011
- Rivnay, Jonathan; Steyrleuthner, Robert; Jimison, Leslie H.
- Macromolecules, Vol. 44, Issue 13
The isotopic effects of deuteration on optoelectronic properties of conducting polymers
journal, January 2014
- Shao, Ming; Keum, Jong; Chen, Jihua
- Nature Communications, Vol. 5, Issue 1
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
Solution-processed small-molecule solar cells with 6.7% efficiency
journal, November 2011
- Sun, Yanming; Welch, Gregory C.; Leong, Wei Lin
- Nature Materials, Vol. 11, Issue 1, p. 44-48
Morphology of polymer-based bulk heterojunction films for organic photovoltaics
journal, January 2011
- Ruderer, Matthias A.; Müller-Buschbaum, Peter
- Soft Matter, Vol. 7, Issue 12
Roles of thermally-induced vertical phase segregation and crystallization on the photovoltaic performance of bulk heterojunction inverted polymer solar cells
journal, January 2011
- Cheun, Hyeunseok; Berrigan, John D.; Zhou, Yinhua
- Energy & Environmental Science, Vol. 4, Issue 9
Unambiguous determination of molecular packing in crystalline donor domains of small molecule solution processed solar cell devices using routine X-ray diffraction techniques
journal, January 2014
- Viterisi, Aurélien; Montcada, Núria F.; Kumar, Challuri Vijay
- Journal of Materials Chemistry A, Vol. 2, Issue 10
Phase-sensitive neutron reflectometry measurements applied in the study of photovoltaic films
journal, August 2010
- Kiel, J. W.; Mackay, M. E.; Kirby, B. J.
- The Journal of Chemical Physics, Vol. 133, Issue 7
Morphological origin for the stratification of P3HT:PCBM blend film studied by neutron reflectometry
journal, November 2013
- Keum, Jong Kahk; Browning, James F.; Xiao, Kai
- Applied Physics Letters, Vol. 103, Issue 22
Polymer Photovoltaic Cells: Enhanced Efficiencies via a Network of Internal Donor-Acceptor Heterojunctions
journal, December 1995
- Yu, G.; Gao, J.; Hummelen, J. C.
- Science, Vol. 270, Issue 5243, p. 1789-1791
Works referencing / citing this record:
The Impact of Device Polarity on the Performance of Polymer-Fullerene Solar Cells
journal, May 2018
- Li, Mengmeng; Li, Junyu; Di Carlo Rasi, Dario
- Advanced Energy Materials, Vol. 8, Issue 22
Recent applications of synchrotron radiation and neutrons in the study of soft matter
journal, February 2017
- Narayanan, Theyencheri; Wacklin, Hanna; Konovalov, Oleg
- Crystallography Reviews, Vol. 23, Issue 3