Skip to main content
SpringerLink
Log in

Subtle Effect of Alkyl Substituted π-Bridges on Dibenzo[a,c]phenazine Based Polymer Donors towards Enhanced Photovoltaic Performance

  • Research Article
  • Published:
Chinese Journal of Polymer Science Aims and scope Submit manuscript

Abstract

Selection of the strategically substituted alkyl chains has a significant effect to modulate the physical properties of conjugated polymers, electro-optical characteristics, and active layer morphology of the corresponding polymer solar cells (PSCs). Herein, we systematically synthesized three dibenzo[a,c]phenazine based D-π-A donor polymers named PBP-C0, PBP-C8, and PBP-C6 with different alkyl substitutions on thiophene π-bridges, without alkyl, 2-ethylhexyl and n-hexyl groups, respectively. The absence of the alkyl chain (PBP-C0) on the π-bridge caused poor solubility and unfavorable miscibility with the Y5 acceptor, leading to the lower photovoltaic performance. The bulky alkyl chain of 2-ethylhexyl on the π-bridge group caused the twisting of PBP-C8 conjugated backbone, which limits the charge transport and also compromises the photovoltaic performance. In contrast, the PBP-C6-with flexible linear alkyl chains has almost planar curvature geometry resulting in the small uniform domain size and appropriate phase separation in the blend film morphology. These favorable properties enhanced the exciton generation to dissociation, charge carrier mobility, and also lowered the charge recombination. Among three polymers, PBP-C6-based devices exhibit the best PCE of 11.60%. From these results, thiophene π-bridge alkyl substitution demonstrated an important strategy to adjust energy level, absorption, and phase separation morphology to enhance the photovoltaic performance of the PSCs.

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

Access this article

Log in via an institution

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

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. Li, Y.; Xu, G.; Cui, C.; Li, Y. Flexible and semitransparent organic solar cells. Adv. Energy. Mater. 2018, 8, 1701791.

    Article  CAS  Google Scholar 

  2. Xu, Y.; Yao, H.; Hou, J. Recent advances in fullerene-free polymer solar cells: materials and devices. Chin. J. Chem. 2019, 37, 207–215.

    Article  CAS  Google Scholar 

  3. Chen, J.; Cao, Y. Development of novel conjugated donor polymers for high-efficiency bulk-heterojunction photovoltaic devices. Acc. Chem. Res. 2009, 42, 1709–1718.

    Article  CAS  PubMed  Google Scholar 

  4. Li, Y. Molecular design of photovoltaic materials for polymer solar cells: toward suitable electronic energy levels and broad absorption. Acc. Chem. Res. 2012, 45, 723–733.

    Article  CAS  PubMed  Google Scholar 

  5. Cheng, Y. J.; Yang, S. H.; Hsu, C. S. Synthesis of conjugated polymers for organic solar cell applications. Chem. Rev. 2009, 109, 5868–5923.

    Article  CAS  PubMed  Google Scholar 

  6. Cui, C.; Li, Y. High-performance conjugated polymer donor materials for polymer solar cells with narrow-bandgap nonfullerene acceptors. Energy Environ. Sci. 2019, 12, 3225–3246.

    Article  CAS  Google Scholar 

  7. Li, G.; Zhu, R.; Yang, Y. Polymer solar cells. Nat. Photonics 2012, 6, 153–161.

    Article  CAS  Google Scholar 

  8. Duan, C.; Ding, L. The new era for organic solar cells: polymer donors. Sci. Bull. 2020, 65, 1422–1424.

    Article  CAS  Google Scholar 

  9. Duan, C.; Ding, L. The new era for organic solar cells: polymer acceptors. Sci. Bull. 2020, 65, 1508–1510.

    Article  CAS  Google Scholar 

  10. Bi, P.; Zhang, S.; Wang, J.; Ren, J.; Hou, J. Progress in organic solar cells: materials, physics and device engineering. Chin. J. Chem. 2021, 39, 2607–2625.

    Article  CAS  Google Scholar 

  11. Yuan, J.; Zhang, Y.; Zhou, L.; Zhang, G.; Yip, H. L.; Lau, T. K.; Lu, X.; Zhu, C.; Peng, H.; Johnson, P. A.; Leclerc, M.; Cao, Y.; Ulanski, J.; Li, Y.; Zou, Y. Single-junction organic solar cell with over 15% efficiency using fused-ring acceptor with electron-deficient core. Joule 2019, 3, 1140–1151.

    Article  CAS  Google Scholar 

  12. Zhang, M.; Guo, X.; Ma, W.; Ade, H.; Hou, J. A large-bandgap conjugated polymer for versatile photovoltaic applications with high performance. Adv. Mater. 2015, 27, 4655–4660.

    Article  CAS  PubMed  Google Scholar 

  13. Zhang, Z.; Li, Y.; Cai, G.; Zhang, Y.; Lu, X.; Lin, Y. Selenium heterocyclic electron acceptor with small urbach energy for as-cast high-performance organic solar cells. J. Am. Chem. Soc. 2020, 142, 18741–18745.

    Article  CAS  PubMed  Google Scholar 

  14. Zhang, Y.; Cai, G.; Li, Y.; Zhang, Z.; Li, T.; Zuo, X.; Lu, X.; Lin, Y. An electron acceptor analogue for lowering trap density in organic solar cells. Adv. Mater. 2021, 33, 2008134.

    Article  CAS  Google Scholar 

  15. Jiang, K.; Wei, Q.; Lai, J. Y. L.; Peng, Z.; Kim, H. K.; Yuan, J.; Ye, L.; Ade, H.; Zou, Y.; Yan, H. Alkyl chain tuning of small molecule acceptors for efficient organic solar cells. Joule 2019, 3, 3020–3033.

    Article  CAS  Google Scholar 

  16. Gao, K.; Kan, Y.; Chen, X.; Liu, F.; Kan, B.; Nian, L.; Wan, X.; Chen, Y.; Peng, X.; Russell, T. P.; Cao, Y.; Jen, A. K. Y. Low-bandgap porphyrins for highly efficient organic solar cells: materials, morphology, and applications. Adv. Mater. 2020, 32, 1906129.

    Article  CAS  Google Scholar 

  17. Zhang, M.; Zhu, L.; Zhou, G.; Hao, T.; Qiu, C.; Zhao, Z.; Hu, Q.; Larson, B. W.; Zhu, H.; Ma, Z.; Tang, Z.; Feng, W.; Zhang, Y.; Russell, T. P.; Liu, F. Single-layered organic photovoltaics with double cascading charge transport pathways: 18% efficiencies. Nat. Commun. 2021, 12, 309.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  18. Ma, Q.; Jia, Z.; Meng, L.; Zhang, J.; Zhang, H.; Huang, W.; Yuan, J.; Gao, F.; Wan, Y.; Zhang, Z.; Li, Y. Promoting charge separation resulting in ternary organic solar cells efficiency over 17.5%. Nano Energy 2020, 78, 105272.

    Article  CAS  Google Scholar 

  19. Ma, R.; Liu, T.; Luo, Z.; Guo, Q.; Xiao, Y.; Chen, Y.; Li, X.; Luo, S.; Lu, X.; Zhang, M.; Li, Y.; Yan, H. Improving open-circuit voltage by a chlorinated polymer donor endows binary organic solar cells efficiencies over 17%. Sci. China Chem. 2020, 63, 325–330.

    Article  CAS  Google Scholar 

  20. Firdaus, Y.; Le Corre, V. M.; Karuthedath, S.; Liu, W.; Markina, A.; Huang, W.; Chattopadhyay, S.; Nahid, M. M.; Nugraha, M. I.; Lin, Y.; Seitkhan, A.; Basu, A.; Zhang, W.; McCulloch, I.; Ade, H.; Labram, J.; Laquai, F.; Andrienko, D.; Koster, L. J. A.; Anthopoulos, T. D. Long-range exciton diffusion in molecular non-fullerene acceptors. Nat. Commun. 2020, 11, 5220.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  21. Hou, R.; Li, M.; Ma, X.; Huang, H.; Lu, H.; Jia, Q.; Liu, Y.; Xu, X.; Li, H. B.; Bo, Z. Noncovalently fused-ring electron acceptors with C2v symmetry for regulating the morphology of organic solar cells. ACS Appl. Mater. Interfaces 2020, 12, 46220–46230.

    Article  CAS  PubMed  Google Scholar 

  22. Nian, L.; Kan, Y.; Gao, K.; Zhang, M.; Li, N.; Zhou, G.; Jo, S. B.; Shi, X.; Lin, F.; Rong, Q.; Liu, F.; Zhou, G.; Jen, A. K. Y. Approaching 16% efficiency in all-small-molecule organic solar cells based on ternary strategy with a highly crystalline acceptor. Joule 2020, 4, 2223–2236.

    Article  CAS  Google Scholar 

  23. Liu, Q.; Fang, J.; Wu, J.; Zhu, L.; Guo, X.; Liu, F.; Zhang, M. Tuning aggregation behavior of polymer donor via molecular-weight control for achieving 17.1% efficiency inverted polymer solar cells. Chin. J. Chem. 2021, 39, 1941–1947.

    Article  CAS  Google Scholar 

  24. Chao, P.; Chen, H.; Zhu, Y.; Lai, H.; Mo, D.; Zheng, N.; Chang, X.; Meng, H.; He, F. A benzo[1,2-b:4,5-c′]dithiophene-4,8-dione-based polymer donor achieving an efficiency over 16. Adv. Mater. 2020, 32, 1907059.

    Article  CAS  Google Scholar 

  25. Liu, Q.; Jiang, Y.; Jin, K.; Qin, J.; Xu, J.; Li, W.; Xiong, J.; Liu, J.; Xiao, Z.; Sun, K.; Yang, S.; Zhang, X.; Ding, L. 18% Efficiency organic solar cells. Sci. Bull. 2020, 65, 272–275.

    Article  CAS  Google Scholar 

  26. Zhao, T.; Wang, H.; Pu, M.; Lai, H.; Chen, H.; Zhu, Y.; Zheng, N.; He, F. Tuning the molecular weight of chlorine-substituted polymer donors for small energy loss. Chin. J. Chem. 2021, 39, 1651–1658.

    Article  CAS  Google Scholar 

  27. Zhang, G.; Ning, H.; Chen, H.; Jiang, Q.; Jiang, J.; Han, P.; Dang, L.; Xu, M.; Shao, M.; He, F.; Wu, Q. Naphthalenothiophene imide-based polymer exhibiting over 17% efficiency. Joule 2021, 5, 931–944.

    Article  CAS  Google Scholar 

  28. Zhu, C.; Meng, L.; Zhang, J.; Qin, S.; Lai, W.; Qiu, B.; Yuan, J.; Wan, Y.; Huang, W.; Li, Y. A quinoxaline-based D-A copolymer donor achieving 17.62% efficiency of organic solar cells. Adv. Mater. 2021, 33, 2100474.

    Article  CAS  Google Scholar 

  29. Sun, C.; Pan, F.; Bin, H.; Zhang, J.; Xue, L.; Qiu, B.; Wei, Z.; Zhang, Z. G.; Li, Y. A low cost and high performance polymer donor material for polymer solar cells. Nat. Commun. 2018, 9, 743.

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  30. Song, H. J.; Lee, T. H.; Han, M. H.; Lee, J. Y.; Moon, D. K. Synthesis of donor-acceptor polymers through control of the chemical structure: improvement of PCE by planar structure of polymer backbones. Polymer 2013, 54, 1072–1079.

    Article  CAS  Google Scholar 

  31. Song, H. J.; Lee, E. J.; Kim, D. H.; Lee, S. M.; Lee, J. Y.; Moon, D. K. Enhancement of external quantum efficiency through steric hindrance of phenazine derivative for white polymer light-emitting diode materials. Synth. Met. 2013, 181, 98–103.

    Article  CAS  Google Scholar 

  32. Zhang, Y.; Zou, J.; Yip, H. L.; Chen, K. S.; Zeigler, D. F.; Sun, Y.; Jen, A. K. Y. Indacenodithiophene and quinoxaline-based conjugated polymers for highly efficient polymer solar cells. Chem. Mater. 2011, 23, 2289–2291.

    Article  CAS  Google Scholar 

  33. He, R.; Yu, L.; Cai, P.; Peng, F.; Xu, J.; Ying, L.; Chen, J.; Yang, W.; Cao, Y. Narrow-band-gap conjugated polymers based on 2,7-dioctyl substituted dibenzo[a,c]phenazine derivatives for polymer solar cells. Macromolecules 2014, 47, 2921–2928.

    Article  CAS  Google Scholar 

  34. Lee, T. H.; Choi, M. H.; Jeon, S. J.; Nam, S. J.; Han, Y. W.; Haw, J. R.; Moon, D. K. Improvement of short circuit current density by intermolecular interaction between polymer backbones for polymer solar cells. Polym. J. 2017, 49, 177–187.

    Article  CAS  Google Scholar 

  35. Sun, Y.; Zhang, C.; Dai, B.; Lin, B.; Yang, H.; Zhang, X.; Guo, L.; Liu, Y. Side chain engineering and conjugation enhancement of benzodithiophene and phenanthrenequnioxaline based conjugated polymers for photovoltaic devices. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1915–1926.

    Article  CAS  Google Scholar 

  36. Jo, E.; Park, J. B.; Lee, W. H.; Kim, J. H.; Jung, I. H.; Hwang, D. H.; Kang, I. N. Synthesis and characterization of a new phenanthrenequinoxaline-based polymer for organic solar cells. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2804–2810.

    Article  CAS  Google Scholar 

  37. Hu, T.; Han, L.; Xiao, M.; Bao, X.; Wang, T.; Sun, M.; Yang, R. Enhancement of photovoltaic performance by increasing conjugation of the acceptor unit in benzodithiophene and quinoxaline copolymers. J. Mater. Chem. C 2014, 2, 8047–8053.

    Article  CAS  Google Scholar 

  38. Mei, J.; Bao, Z. Side chain engineering in solution-processable conjugated polymers. Chem. Mater. 2014, 26, 604–615.

    Article  CAS  Google Scholar 

  39. Osaka, I.; Saito, M.; Koganezawa, T.; Takimiya, K. Thiophenethiazolothiazole copolymers: significant impact of side chain composition on backbone orientation and solar cell performances. Adv. Mater. 2014, 26, 331–338.

    Article  CAS  PubMed  Google Scholar 

  40. Zhang, C.; Sun Y.; Dai B.; Zhang, X. Q.; Yang, H.; Lin, B. P.; Guo, L. X. Resent progress in side-chain engineering of organic photovoltaic conjugated polymer. Chin. J. Org. Chem. 2014, 34, 1701–1716.

    Article  CAS  Google Scholar 

  41. Li, G.; Zhao, B.; Kang, C.; Lu, Z.; Li, C.; Dong, H.; Hu, W.; Wu, H.; Bo, Z. Side chain influence on the morphology and photovoltaic performance of 5-fluoro-6-alkyloxybenzothiadiazole and benzodithiophene based conjugated polymers. ACS Appl. Mater. Interfaces 2015, 7, 10710–10717.

    Article  CAS  PubMed  Google Scholar 

  42. Osaka, I.; Takimiya, K. Backbone orientation in semiconducting polymers. Polymer 2015, 59, A1–A15.

    Article  CAS  Google Scholar 

  43. Jin, Y.; Chen, Z.; Dong, S.; Zheng, N.; Ying, L.; Jiang, X. F.; Liu, F.; Huang, F.; Cao, Y. A novel naphtho[1,2-c:5,6-c′]bis([1,2,5]thiadiazole)-based narrow-bandgap π-conjugated polymer with power conversion efficiency over 10%. Adv. Mater. 2016, 28, 9811–9818.

    Article  CAS  PubMed  Google Scholar 

  44. Kim, J. H.; Wood, S.; Park, J. B.; Wade, J.; Song, M.; Yoon, S. C.; Jung, I. H.; Kim, J. S.; Hwang, D. H. Optimization and analysis of conjugated polymer side chains for high-performance organic photovoltaic cells. Adv. Funct. Mater. 2016, 26, 1517–1525.

    Article  CAS  Google Scholar 

  45. Dutta, P.; Park, H.; Lee, W. H.; Kang, I. N.; Lee, S. H. Synthesis characterization and bulk-heterojunction photovoltaic applications of new naphtho[1,2-b:5,6-b′]dithiophene-quinoxaline containing narrow band gap D-A conjugated polymers. Polym. Chem. 2014, 5, 132–143.

    Article  CAS  Google Scholar 

  46. El-Shehawy, A. A.; Abdo, N. I.; El-Hendawy, M. M.; Abdallah, A. R. I. A.; Lee, J. S. Dialkylthienosilole and N-alkyldithienopyrrole-based copolymers: synthesis, characterization, and photophysical study. J. Phys. Org. Chem. 2020, 33, e4063.

    Article  CAS  Google Scholar 

  47. Du, M.; Geng, Y.; Ji, H.; Li, G.; Xiao, Y.; Zuo, K.; Liu, Y.; Guo, Q.; Tang, A.; Zhou, E. The optimization of π-bridge for trialkylsilyl substituted D-π-A photovoltaic polymers. Dyes Pigm. 2021, 194, 109609.

    Article  CAS  Google Scholar 

  48. Rehman, T.; Liu, Z. X.; Lau, T. K.; Yu, Z. P.; Shi, M.; Lu, X.; Li, C. Z.; Chen, H. Influence of bridging groups on the photovoltaic properties of wide bandgap poly(BDTT-alt-BDD)s. ACS Appl. Mater. Interfaces 2019, 11, 1394–1401.

    Article  CAS  PubMed  Google Scholar 

  49. Mondal, R.; Ko, S.; Verploegen, E.; Becerril, H. A.; Toney, M. F.; Bao, Z. Side chain engineering of fused aromatic thienopyrazine based low band-gap polymers for enhanced charge carrier mobility. J. Mater. Chem. 2011, 21, 1537–1543.

    Article  CAS  Google Scholar 

  50. Lee, Y.; Nam, Y. M.; Jo, W. H. Enhanced device performance of polymer solar cells by planarization of quinoxaline derivative in a low-bandgap polymer. J. Mater. Chem. 2011, 21, 8583–8590.

    Article  CAS  Google Scholar 

  51. Körzdörfer, T.; Brédas, J. L. Organic electronic materials: recent advances in the DFT description of the ground and excited states using tuned range-separated hybrid functionals. Acc. Chem. Res. 2014, 47, 3284–3291.

    Article  PubMed  CAS  Google Scholar 

Download references

Acknowledgments

This work was financially supported by the National Natural Science Foundation of China (Nos. 21733005 and 21975115), the Shenzhen Fundamental Research Program (Nos. JCYJ201 90809163011543, JCYJ20200109140801751 and JCYJ2021032 4120010028), the Guangdong Provincial Key Laboratory of Catalysis (No. 2020B121201002), the Guangdong Innovative and Entrepreneurial Research Team Program (No. 2016ZT06G587), and the Shenzhen Sci-Tech Fund (No. KYTDPT 20181011104 007). We also thank the SUSTech Core Research Facilities for AFM and TEM measurements.

Author information

Author notes

  1. These authors contributed equally to this work.

Authors and Affiliations

  1. Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China

    Chun-Xian Ke, Xue Lai, Heng-Tao Wang, Ming-Rui Pu, Tahir Rehman, Yu-Lin Zhu & Feng He

  2. Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, 518055, China

    Feng He

Authors
  1. Chun-Xian Ke
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Xue Lai
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Heng-Tao Wang
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Ming-Rui Pu
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Tahir Rehman
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Yu-Lin Zhu
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Feng He
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Feng He.

Additional information

Notes

The authors declare no competing financial interest.

Electronic Supplementary Information

10118_2022_2719_MOESM1_ESM.pdf

Subtle Effect of Alkyl Substituted π-Bridges on Dibenzo[a,c]phenazine Based Polymer Donors towards Enhanced Photovoltaic Performance

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Ke, CX., Lai, X., Wang, HT. et al. Subtle Effect of Alkyl Substituted π-Bridges on Dibenzo[a,c]phenazine Based Polymer Donors towards Enhanced Photovoltaic Performance. Chin J Polym Sci 40, 889–897 (2022). https://doi.org/10.1007/s10118-022-2719-z

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10118-022-2719-z

Keywords

Search

Navigation