Skip to main content
Log in

A GIWAXS study of crystallization in annealed conjugated polymers presenting technological interest for organic solar cell applications

  • Published:
Journal of Materials Science: Materials in Electronics Aims and scope Submit manuscript

Abstract

Thermal annealing represents an important stage for the fabrication of active layers for organic solar cells. The crystalline organization improves charge carrier mobility and induces the proper morphology of the electron donor and electron acceptor. In this work, the optimal annealing time for maximization of crystalline volume fraction and the crystallization mechanisms of conjugated polymer films synthesized in our group for solar cell application has been determined by grazing incidence wide-angle X-ray scattering (GIWAXS). By following the evolution of the diffraction peak position, the peak area, and the full width at half maximum (FWHM), it was possible to determine the proper annealing time and to identify the stages corresponding to crystallites formation and growth for poly(butyl octyl benzodithiophene-co-benzothiadiazole) (PBOBDTBTD), poly(butyl octyl benzodithiophene-co-thiophene) (PBOBDTTh), and two different poly(3-hexylthiophene), one of lower molar mass synthesized through Kumada mechanism (P3HTA) and other of higher molar mass through Grimm mechanism (P3HTB). The results show that annealing time increases with polymer backbone rigidity, around 1200 s, 800 s, and 400 s for PBOBDTBTD, PBOBDTTh, and P3HT, respectively. Thus, crystallization in PBOBDTBTD and P3HT mainly occurs through several stages of crystallite formation. In contrast, crystallite growth is significant in PBOBDTTh, promoted both by the flexibility of the polymer chain and the symmetry of the structural unit position in the backbone. For all polymers, an unexpected increase of interplanar distance during crystallites formation and growth has been detected. We attribute this behavior to the confinement of the chains in thin films, which may inhibit the interdigitation effect usually observed in bulk polymer and associated with increased packing between side chains, diminishing the average distance among conjugated backbones. Such inhibition seems to be more pronounced for PBOBDTBTD due to the greater rigidity of the polymer backbone, and less intense for PBOBDTTh, due to the higher molar mass of this polymer than P3HT.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8

Similar content being viewed by others

References

  1. A. Anctil, E. Lee, R.R. Lunt, Net energy and cost benefit of transparent organic solar cells in building-integrated applications. Appl. Ener. 261, 114429 (2020)

    Article  Google Scholar 

  2. L.K. Jagadamma, M.T. Sajjad, V. Savikhin, M.F. Toney, I.D.W. Samuel, Correlating photovoltaic properties of a PTB7-Th:PC71BM blend to photophysics and microstructure as a function of thermal annealing. J. Mater. Chem. A 5, 14646 (2017)

    Article  Google Scholar 

  3. J.L. Wang, K.K. Liu, J. Yan, Z. Wu, F. Liu, F. Xiao, Z.F. Chang, H.B. Wu, Y. Cao, T.P. Russell, Series of multifluorine substituted oligomers for organic solar cells with efficiency over 9% and fill factor of 0.77 by combination thermal and solvent vapor annealing. J. Am. Chem. Soc. 138, 7687 (2016)

    Article  CAS  Google Scholar 

  4. C.H. To, A. Ng, Q. Dong, A.B. Djurišić, J.A. Zapien, W.K. Chan, C. Surya, Effect of PTB7 properties on the performance of PTB7:PC71BM solar cells. ACS Appl. Mater. Inter. 7, 13198 (2015)

    Article  CAS  Google Scholar 

  5. H. Sirringhaus, P. Brown, P. Friend, M. Nielsen, K. Bechgaard, A.J.H. Spiering, Two-dimensional charge transport in conjugated polymers. Nature 401, 685 (1999)

    Article  CAS  Google Scholar 

  6. K.R. Amundson, B.J. Sapjeta, A.J. Lovinger, Z. Bao, An in-plane anisotropic organic semiconductor based upon poly(3-hexyl thiophene). Thin Solid Films 414, 143 (2002)

    Article  CAS  Google Scholar 

  7. B. Fluegel, Y. Zhang, A. Mascarenhas, X. Huang, J. Li, Electronic properties of hybrid organic-inorganic semiconductors. Phys. Rev. B – Conden. Matt. Mater. Phys. 70, 2 (2004)

    Google Scholar 

  8. J.J.R. Arias, L. Crociani, I.T. Soares, I.C. Mota, B.P.S. Santos, R. Valaski, M.D.F.V. Marques, Synthesis of conjugated polymers with directly coupled 2-butyloctyloxybenzodithiophene and benzothiadazole units for application as active layers in organic solar cells. React. Func. Polym. 144, 104355 (2019)

    Article  CAS  Google Scholar 

  9. M. Aryal, K. Trivedi, W. Hu, Nano-confinement induced chain alignment in ordered P3HT nanostructures defined by nanoimprint lithography. ACS Nano 3, 3085 (2009)

    Article  CAS  Google Scholar 

  10. C. Shen, Y.H. Lee, Y.P. Lee, C.J. Chiang, F.K. Wei, C.H. Wu, K.C. Kau, H.W. Liu, C.C. Hsieh, L. Wang, C.A. Dai, Self-organization and phase transformation of all π-conjugated diblock copolymers and its applications in organic solar cells. React. Funct. Polym. 108, 94 (2016)

    Article  CAS  Google Scholar 

  11. S.C. Chang, Y.J. Hsiao, T.S. Li, Selecting annealing temperature of P3HT/PCBM incorporated with nano-diamonds using thermal desorption spectroscopy. Int. J. Electrochem. Sci. 10, 1658 (2015)

    Google Scholar 

  12. D.M. González, C.J. Schaffer, S. Pröller, J. Schlipf, L. Song, S. Bernstorff, E.M. Herzig, P. Müller-Buschbaum, Codependence between crystalline and photovoltage evolutions in P3HT:PCBM solar cells probed with in-operando GIWAXS. ACS Appl. Mater. Inter. 9, 3282 (2017)

    Article  CAS  Google Scholar 

  13. C.D. Liman, S. Choi, D.W. Breiby, J.E. Cochran, M.F. Toney, E.J. Kramer, M.L. Chabinyc, Two-dimensional GIWAXS reveals a transient crystal phase in solution-processed thermally converted tetrabenzoporphyrin. J. Phys. Chem. B 117, 14557 (2013)

    Article  CAS  Google Scholar 

  14. M. Jeffries-El, G. Sauvé, R.D. McCullough, Facile synthesis of end-functionalized regioregular poly(3-alkylthiophene)s via modified Grignard metathesis reaction. Macromolecules 38, 10346 (2005)

    Article  CAS  Google Scholar 

  15. B.P.S. Santos, J.J.R. Arias, M.F.V. Marques, J.G.M. Furtado, L.A. Silva, R.A. Simão, Synthesis and characterization of poly(3-Hexylthiophene) for organic solar cells. Macromol. Symp. 383, 1 (2019)

    Google Scholar 

  16. P. Müller-Buschbaum, The active layer morphology of organic solar cells probed with grazing incidence scattering techniques. Adv. Mater. 26, 7692 (2014)

    Article  CAS  Google Scholar 

  17. Hammersley AP (1997) ESRF Internal Report, ESRF97HA02T, FIT2D: An Introduction and Overview.

  18. Hammersley AP (1998) ESRF Internal Report, ESRF98HA01T, FIT2D V9.129 Reference Manual 3.1.

  19. M.A. Ruderer, S.M. Prams, M. Rawolle, Q. Zhong, J. Perlich, S.V. Roth, P. Müller-Buschbaum, Influence of annealing and blending of photoactive polymers on their crystalline structure. J. Phys. Chem. B 114, 15451 (2010)

    Article  CAS  Google Scholar 

  20. S. Londono-Restrepo, R. Jeronimo-Cruz, B. Millan-Malo, E. Rivera-Munoz, M. Rodriguez-Garcia, Effect of the nano crystal size on the X-ray diffraction patterns of biogenic hydroxyapatite from human, bovine, and porcine bones. Sci. Rep. 9, 5915 (2019)

    Article  CAS  Google Scholar 

  21. J. Rubio Arias, I.C. Mota, M.F.V. Marques, Synthesis of thiophene-benzodithiophene wide bandgap polymer and GIWAXS evaluation of thermal annealing with potential for application in ternary polymer solar cells. Polym. Adv. Technol. 32(1507), 1517 (2020)

    Google Scholar 

  22. K.Y. Wu, C.C. Chiu, W.T. Chuang, C.L. Wang, C.S. Hsu, The backbone rigidity and its influence on the morphology and charge mobility of FBT based conjugated polymers. Polym. Chem. 6, 1309 (2015)

    Article  CAS  Google Scholar 

  23. M. Moroni, J. Le Moigne, T.A. Pham, J.Y. Bigot, Rigid rod conjugated polymers for nonlinear optics. 3. Intramolecular H bond effects on poly(phenyleneethynylene) chains. Macromolecules 30, 1964 (1997)

    Article  CAS  Google Scholar 

  24. M. Aldissi, Effect of chain rigidity on conductivity of conjugated polymers. Synth. Met. 17, 235 (1987)

    Article  CAS  Google Scholar 

  25. S. Debnath, S. Chithiravel, S. Sharma, A. Bedi, K. Krishnamoorthy, S.S. Zade, Selenium-containing fused bicyclic heterocycle diselenolodiselenole: field effect transistor study and structure-property relationship. ACS Appl. Mater. Interfaces. 8, 18222 (2016)

    Article  CAS  Google Scholar 

  26. K.S. Ahn, H. Jo, J.B. Kim, I. Seo, H.H. Lee, D.R. Lee, Structural transition and interdigitation of alkyl side chains in the conjugated polymer poly (3-hexylthiophene) and their effects on the device performance of the associated organic field-effect transistor. ACS Appl. Mater. Interfaces. 12(1), 1142–1150 (2019)

    Article  CAS  Google Scholar 

  27. J.J.R. Arias, M.D.F.V. Marques, Performance of poly(3-hexylthiophene) in bulk heterojunction solar cells: Influence of polymer size and size distribution. React. Funct. Polym. 113, 58 (2017)

    Article  CAS  Google Scholar 

  28. K.M. Knoblock, C.J. Silvestri, D.M. Collard, Stacked conjugated oligomers as molecular models to examine interchain interactions in conjugated materials. J. Am. Chem. Soc. 128, 13680 (2006)

    Article  CAS  Google Scholar 

  29. D.A.M. Egbe, S. Türk, S. Rathgeber, F. Kühnlenz, R. Jadhav, A. Wild, E. Birckner, G. Adam, A. Pivrikas, V. Cimrova, G. Knör, N.S. Sariciftci, H. Hoppe, Anthracene based conjugated polymers: Correlation between π-π- Stacking ability, photophysical properties, charge carrier mobility, and photovoltaic performance. Macromolecule 43, 1261 (2010)

    Article  CAS  Google Scholar 

  30. J.H. Dou, Y.Q. Zheng, T. Lei, S.D. Zhang, Z. Wang, W.B. Zhang, J.Y. Wang, J. Pei, Systematic investigation of side-chain branching position effect on electron carrier mobility in conjugated polymers. Adv. Func. Mater. 24, 6270 (2014)

    Article  CAS  Google Scholar 

  31. P. Keg, A. Lohani, D. Fichou, Y.M. Lam, Y. Wu, B.S. Ong, S.G. Mhaisalkar, Direct observation of alkyl chain interdigitation in conjugated polyquarterthiophene self-organized on graphite surfaces. Macromol. Rapid Commun. 29, 1197 (2008)

    Article  CAS  Google Scholar 

  32. B.G. Kim, E.J. Jeong, J.W. Chung, S. Seo, B. Koo, J. Kim, A molecular design principle of lyotropic liquid-crystalline conjugated polymers with directed alignment capability for plastic electronics. Nat. Mater. 12, 659 (2013)

    Article  CAS  Google Scholar 

  33. Y. Olivier, D. Niedzialek, V. Lemaur, W. Pisula, K. Müllen, U. Koldemir, J.R. Reynolds, R. Lazzaroni, J. Cornil, D. Beljonne, 25th anniversary article: High-mobility hole and electron transport conjugated polymers: How structure defines function. Adv. Mater. 26, 2119 (2014)

    Article  CAS  Google Scholar 

  34. L. Xu, Y. Liu, S. Lei, Self Assembly of conjugated oligomers and polymers at the interface: structure and properties. Nanoscale 4, 4399 (2010)

    Article  CAS  Google Scholar 

  35. Y. Pan, J. Huang, D. Gao, Z. Chen, W. Zhang, G. Yu, An insight into the role of side chains in the microstructure and carrier mobility of high-performance conjugated polymers. Polym. Chem. 12(16), 2471–2480 (2021)

    Article  CAS  Google Scholar 

  36. Y.W. Huang, Y.C. Lin, H.C. Yen, C.K. Chen, W.Y. Lee, W.C. Chen, C.C. Chueh, High mobility preservation of near amorphous conjugated polymers in the stretched states enabled by biaxially-extended conjugated side-chain design. Chem. Mater. 32(17), 7370–7382 (2020)

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This research used resources of the Brazilian Synchrotron Light Laboratory (LNLS), an open national facility operated by the Brazilian Center for Research in Energy and Materials (CNPEM), supported by the Brazilian Ministry of Science, Technology, Innovations, and Communications (MCTIC). The XRD2 beamline staff is acknowledged for their assistance during the experiments, especially Dr. Antonio Gasperini, who made possible data reduction. We also thank the funding agency FAPERJ for the financial support.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Maria de Fatima Vieira Marques.

Ethics declarations

Conflict of interest

The authors declare no conflict of interest.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Rubio Arias, J.J., Custodio Mota, I., Schmidt Albuquerque, L. et al. A GIWAXS study of crystallization in annealed conjugated polymers presenting technological interest for organic solar cell applications. J Mater Sci: Mater Electron 33, 1838–1850 (2022). https://doi.org/10.1007/s10854-021-07383-3

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10854-021-07383-3

Navigation