A Nonchlorinated Solvent-Processable Fluorinated Planar Conjugated Polymer for Flexible Field-Effect Transistors

Myeongjae Lee, Min Je Kim, Suhee Ro, Shinyoung Choi, Seon Mi Jin, Hieu Dinh Nguyen, Jeehye Yang, Kyung Koo Lee, Dong Un Lim, Eunji Lee, Moon Sung Kang, Jong-Ho Choi, Jeong Ho Cho, Bongsoo Kim

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

High carrier mobilities have recently been achieved in polymer field effect transistors (FETs). However, many of these polymer FET devices require the use of chlorinated solvents such as chloroform (CF), chlorobenzene (CB), and o-dichlorobenzene (DCB) during fabrication. The use of these solvents is highly restricted in industry because of health and environmental issues. Here, we report the synthesis of a low band gap (1.43 eV, 870 nm) semiconducting polymer (PDPP2DT-F2T2) having a planar geometry, which can be readily processable with nonchlorinated solvents such as toluene (TOL), o-xylene (XY), and 1,2,4-trimethylbenzene (TMB). We performed structural characterization of PDPP2DT-F2T2 films prepared from different solvents, and the electrical properties of the films were measured in the context of FETs. The devices exhibited an ambipolar behavior with hole dominant transport. Hole mobilities increased with increasing boiling point (bp) of the nonchlorinated solvents: 0.03, 0.05, and 0.10 cm2 V-1 s-1 for devices processed using TOL, XY, and TMB, respectively. Thermal annealing further improved the FET performance. TMB-based polymer FETs annealed at 200 °C yielded a maximum hole mobility of 1.28 cm2 V-1 s-1, which is far higher than the 0.43 cm2 V-1 s-1 obtained from the CF-based device. This enhancement was attributed to increased interchain interactions as well as improved long-range interconnection between fibrous domains. Moreover, all of the nonchlorinated solutions generated purely edge-on orientations of the polymer chains, which is highly beneficial for carrier transport in FET devices. Furthermore, we fabricated an array of flexible TMB-processed PDPP2DT-F2T2 FETs on the plastic PEN substrates. These devices demonstrated excellent carrier mobilities and negligible degradation after 300 bending cycles. Overall, we demonstrated that the organized assembly of polymer chains can be achieved by slow drying using high bp nonchlorinated solvents and a post thermal treatment. Furthermore, we showed that polymer FETs processed using high bp nonhalogenated solvents may outperform those processed using halogenated solvents.

Original languageEnglish
Pages (from-to)28817-28827
Number of pages11
JournalACS Applied Materials and Interfaces
Volume9
Issue number34
DOIs
Publication statusPublished - 2017 Aug 30

Keywords

  • carrier mobility
  • flexible electronics
  • low bandgap polymer
  • mechanical stability
  • nonchlorinated solvent
  • organic transistor

ASJC Scopus subject areas

  • Materials Science(all)

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  • Cite this

    Lee, M., Kim, M. J., Ro, S., Choi, S., Jin, S. M., Nguyen, H. D., Yang, J., Lee, K. K., Lim, D. U., Lee, E., Kang, M. S., Choi, J-H., Cho, J. H., & Kim, B. (2017). A Nonchlorinated Solvent-Processable Fluorinated Planar Conjugated Polymer for Flexible Field-Effect Transistors. ACS Applied Materials and Interfaces, 9(34), 28817-28827. https://doi.org/10.1021/acsami.7b08071