Electrode Materials, Thermal Annealing Sequences, and Lateral/Vertical Phase Separation of Polymer Solar Cells from Multiscale Molecular Simulations

Handle URI:
http://hdl.handle.net/10754/598142
Title:
Electrode Materials, Thermal Annealing Sequences, and Lateral/Vertical Phase Separation of Polymer Solar Cells from Multiscale Molecular Simulations
Authors:
Lee, Cheng-Kuang; Wodo, Olga; Ganapathysubramanian, Baskar; Pao, Chun-Wei
Abstract:
© 2014 American Chemical Society. The nanomorphologies of the bulk heterojunction (BHJ) layer of polymer solar cells are extremely sensitive to the electrode materials and thermal annealing conditions. In this work, the correlations of electrode materials, thermal annealing sequences, and resultant BHJ nanomorphological details of P3HT:PCBM BHJ polymer solar cell are studied by a series of large-scale, coarse-grained (CG) molecular simulations of system comprised of PEDOT:PSS/P3HT:PCBM/Al layers. Simulations are performed for various configurations of electrode materials as well as processing temperature. The complex CG molecular data are characterized using a novel extension of our graph-based framework to quantify morphology and establish a link between morphology and processing conditions. Our analysis indicates that vertical phase segregation of P3HT:PCBM blend strongly depends on the electrode material and thermal annealing schedule. A thin P3HT-rich film is formed on the top, regardless of bottom electrode material, when the BHJ layer is exposed to the free surface during thermal annealing. In addition, preferential segregation of P3HT chains and PCBM molecules toward PEDOT:PSS and Al electrodes, respectively, is observed. Detailed morphology analysis indicated that, surprisingly, vertical phase segregation does not affect the connectivity of donor/acceptor domains with respective electrodes. However, the formation of P3HT/PCBM depletion zones next to the P3HT/PCBM-rich zones can be a potential bottleneck for electron/hole transport due to increase in transport pathway length. Analysis in terms of fraction of intra- and interchain charge transports revealed that processing schedule affects the average vertical orientation of polymer chains, which may be crucial for enhanced charge transport, nongeminate recombination, and charge collection. The present study establishes a more detailed link between processing and morphology by combining multiscale molecular simulation framework with an extensive morphology feature analysis, providing a quantitative means for process optimization.
Citation:
Lee C-K, Wodo O, Ganapathysubramanian B, Pao C-W (2014) Electrode Materials, Thermal Annealing Sequences, and Lateral/Vertical Phase Separation of Polymer Solar Cells from Multiscale Molecular Simulations. ACS Applied Materials & Interfaces 6: 20612–20624. Available: http://dx.doi.org/10.1021/am506015r.
Publisher:
American Chemical Society (ACS)
Journal:
ACS Applied Materials & Interfaces
Issue Date:
10-Dec-2014
DOI:
10.1021/am506015r
PubMed ID:
25373018
Type:
Article
ISSN:
1944-8244; 1944-8252
Sponsors:
C.-K.L. and C.-W.P. thank for the Research Center for Applied Science, Academia Sinica, Academia Sinica Thematic project no. AS-103-SS-A02, and the National Science Council of Taiwan (project nos. NSC 99-2112-M-001-004-MY3 and 102-2628-M-001-004-MY3) for financial support, and the National Center for High Performance Computing for computational support. C.-K.L. also is thankful for the support of the talent development program between Academia Sinica of Taiwan ROC and elite American universities and research institutes. O.W. and B.G. thank the National Science Foundation for partial support (NSF CAREER 1149365, NSF 1236839) and computing support via XSEDE (CTS110007). B.G. also thanks KAUST CRG for partial support.
Appears in Collections:
Publications Acknowledging KAUST Support

Full metadata record

DC FieldValue Language
dc.contributor.authorLee, Cheng-Kuangen
dc.contributor.authorWodo, Olgaen
dc.contributor.authorGanapathysubramanian, Baskaren
dc.contributor.authorPao, Chun-Weien
dc.date.accessioned2016-02-25T13:13:28Zen
dc.date.available2016-02-25T13:13:28Zen
dc.date.issued2014-12-10en
dc.identifier.citationLee C-K, Wodo O, Ganapathysubramanian B, Pao C-W (2014) Electrode Materials, Thermal Annealing Sequences, and Lateral/Vertical Phase Separation of Polymer Solar Cells from Multiscale Molecular Simulations. ACS Applied Materials & Interfaces 6: 20612–20624. Available: http://dx.doi.org/10.1021/am506015r.en
dc.identifier.issn1944-8244en
dc.identifier.issn1944-8252en
dc.identifier.pmid25373018en
dc.identifier.doi10.1021/am506015ren
dc.identifier.urihttp://hdl.handle.net/10754/598142en
dc.description.abstract© 2014 American Chemical Society. The nanomorphologies of the bulk heterojunction (BHJ) layer of polymer solar cells are extremely sensitive to the electrode materials and thermal annealing conditions. In this work, the correlations of electrode materials, thermal annealing sequences, and resultant BHJ nanomorphological details of P3HT:PCBM BHJ polymer solar cell are studied by a series of large-scale, coarse-grained (CG) molecular simulations of system comprised of PEDOT:PSS/P3HT:PCBM/Al layers. Simulations are performed for various configurations of electrode materials as well as processing temperature. The complex CG molecular data are characterized using a novel extension of our graph-based framework to quantify morphology and establish a link between morphology and processing conditions. Our analysis indicates that vertical phase segregation of P3HT:PCBM blend strongly depends on the electrode material and thermal annealing schedule. A thin P3HT-rich film is formed on the top, regardless of bottom electrode material, when the BHJ layer is exposed to the free surface during thermal annealing. In addition, preferential segregation of P3HT chains and PCBM molecules toward PEDOT:PSS and Al electrodes, respectively, is observed. Detailed morphology analysis indicated that, surprisingly, vertical phase segregation does not affect the connectivity of donor/acceptor domains with respective electrodes. However, the formation of P3HT/PCBM depletion zones next to the P3HT/PCBM-rich zones can be a potential bottleneck for electron/hole transport due to increase in transport pathway length. Analysis in terms of fraction of intra- and interchain charge transports revealed that processing schedule affects the average vertical orientation of polymer chains, which may be crucial for enhanced charge transport, nongeminate recombination, and charge collection. The present study establishes a more detailed link between processing and morphology by combining multiscale molecular simulation framework with an extensive morphology feature analysis, providing a quantitative means for process optimization.en
dc.description.sponsorshipC.-K.L. and C.-W.P. thank for the Research Center for Applied Science, Academia Sinica, Academia Sinica Thematic project no. AS-103-SS-A02, and the National Science Council of Taiwan (project nos. NSC 99-2112-M-001-004-MY3 and 102-2628-M-001-004-MY3) for financial support, and the National Center for High Performance Computing for computational support. C.-K.L. also is thankful for the support of the talent development program between Academia Sinica of Taiwan ROC and elite American universities and research institutes. O.W. and B.G. thank the National Science Foundation for partial support (NSF CAREER 1149365, NSF 1236839) and computing support via XSEDE (CTS110007). B.G. also thanks KAUST CRG for partial support.en
dc.publisherAmerican Chemical Society (ACS)en
dc.subjectbulk heterojunctionen
dc.subjectcoarse-grained molecular simulationsen
dc.subjectelectron/hole transporten
dc.subjectnanomorphologyen
dc.subjectpolymer solar cellsen
dc.subjectthermal annealingen
dc.subjectvertical phase segregationen
dc.titleElectrode Materials, Thermal Annealing Sequences, and Lateral/Vertical Phase Separation of Polymer Solar Cells from Multiscale Molecular Simulationsen
dc.typeArticleen
dc.identifier.journalACS Applied Materials & Interfacesen
dc.contributor.institutionAcademia Sinica Taiwan, Nankang, Taiwanen
dc.contributor.institutionUC Berkeley, Berkeley, United Statesen
dc.contributor.institutionIowa State University, Ames, United Statesen
dc.contributor.institutionUniversity at Buffalo State University of New York, Buffalo, United Statesen

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