Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Chemically fixed p–n heterojunctions for polymer electronics by means of covalent B–F bond formation


Widely used solid-state devices fabricated with inorganic semiconductors, including light-emitting diodes and solar cells, derive much of their function from the p–n junction. Such junctions lead to diode characteristics and are attained when p-doped and n-doped materials come into contact with each other. Achieving bilayer p–n junctions with semiconducting polymers has been hindered by difficulties in the deposition of thin films with independent p-doped and n-doped layers1,2. Here we report on how to achieve permanently fixed organic p–n heterojunctions by using a cationic conjugated polyelectrolyte with fluoride counteranions and an underlayer composed of a neutral conjugated polymer bearing anion-trapping functional groups. Application of a bias leads to charge injection and fluoride migration into the neutral layer, where irreversible covalent bond formation takes place. After the initial charging and doping, one obtains devices with no delay in the turn on of light-emitting electrochemical behaviour and excellent current rectification. Such devices highlight how mobile ions in organic media can open opportunities to realize device structures in ways that do not have analogies in the world of silicon and promise new opportunities for integrating organic materials within technologies now dominated by inorganic semiconductors.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Design and materials for chemically fixed heterojunctions.
Figure 2: Change in time response by fixing p–n junction.
Figure 3: Thickness dependence of time response.
Figure 4: LJV characteristics of fixed p–n junction device.


  1. 1

    Cheng, C. H. W. & Lonergan, M. C. A conjugated polymer pn junction. J. Am. Chem. Soc. 126, 10536–10537 (2004).

    CAS  Article  Google Scholar 

  2. 2

    Pfeiffer, M. et al. Doped organic semiconductors: Physics and application in light emitting diodes. Org. Electron. 4, 89–103 (2003).

    CAS  Article  Google Scholar 

  3. 3

    Pei, Q. B., Yu, G., Zhang, C., Yang, Y. & Heeger, A. J. Polymer light-emitting electrochemical-cells. Science 269, 1086–1088 (1995).

    CAS  Article  Google Scholar 

  4. 4

    Pachler, P., Wenzl, F. P., Scherf, U. & Leising, G. The efficiency of light-emitting electrochemical cells. J. Phys. Chem. B 109, 6020–6024 (2005).

    CAS  Article  Google Scholar 

  5. 5

    Kervella, Y., Armand, M. & Stephan, O. Organic light-emitting electrochemical cells based on polyfluorene. Investigation of the failure modes. J. Electrochem. Soc. 148, H155–H160 (2001).

    CAS  Article  Google Scholar 

  6. 6

    Smith, D. L. Steady state model for polymer light-emitting electrochemical cells. J. Appl. Phys. 81, 2869–2880 (1997).

    CAS  Article  Google Scholar 

  7. 7

    Matyba, P., Maturova, K., Kemerink, M., Robinson, N. D. & Edman, L. The dynamic organic p–n junction. Nature Mater. 8, 672–676 (2009).

    CAS  Article  Google Scholar 

  8. 8

    Gao, J., Yu, G. & Heeger, A. J. Polymer light-emitting electrochemical cells with frozen p–i–n junction. Appl. Phys. Lett. 71, 1293–1295 (1997).

    CAS  Article  Google Scholar 

  9. 9

    Gao, J., Li, Y. F., Yu, G. & Heeger, A. J. Polymer light-emitting electrochemical cells with frozen junctions. J. Appl. Phys. 86, 4594–4599 (1999).

    CAS  Article  Google Scholar 

  10. 10

    Leger, J. M., Patel, D. G., Rodovsky, D. B. & Bartholomew, G. P. Polymer photovoltaic devices employing a chemically fixed p–i–n junction. Adv. Funct. Mater. 18, 1212–1219 (2008).

    CAS  Article  Google Scholar 

  11. 11

    Leger, J. M., Rodovsky, D. B. & Bartholomew, G. R. Self-assembled, chemically fixed homojunctions in semiconducting polymers. Adv. Mater. 18, 3130–3134 (2006).

    CAS  Article  Google Scholar 

  12. 12

    Yamaguchi, S., Shirasaka, T., Akiyama, S. & Tamao, K. Dibenzoborole-containing pi-electron systems: Remarkable fluorescence change based on the ‘on/off’ control of the p(pi)–pi* conjugation. J. Am. Chem. Soc. 124, 8816–8817 (2002).

    CAS  Article  Google Scholar 

  13. 13

    Kubo, Y. et al. A colorimetric and ratiometric chemosensor with three emission changes: Fluoride ion sensing by a triarylborane–porphyrin conjugate. Angew. Chem. Int. Ed. 42, 2036–2040 (2003).

    CAS  Article  Google Scholar 

  14. 14

    Garcia, A., Brzezinski, J. Z. & Nguyen, T. Q. Cationic conjugated polyelectrolyte electron injection layers: Effect of halide counterions. J. Phys. Chem. C 113, 2950–2954 (2009).

    CAS  Article  Google Scholar 

  15. 15

    Steuerman, D. W. et al. Imaging the interfaces of conjugated polymer optoelectronic devices. Adv. Mater. 20, 528–534 (2008).

    CAS  Article  Google Scholar 

  16. 16

    Hoven, C. V., Garcia, A., Bazan, G. C. & Nguyen, T. Q. Recent applications of conjugated polyelectrolytes in optoelectronic devices. Adv. Mater. 20, 3793–3810 (2008).

    CAS  Article  Google Scholar 

  17. 17

    Wu, H. B. et al. Efficient electron injection from a bilayer cathode consisting of aluminum and alcohol-/water-soluble conjugated polymers. Adv. Mater. 16, 1826–1830 (2004).

    CAS  Article  Google Scholar 

  18. 18

    Hoven, C. V. et al. Electron injection into organic semiconductor devices from high work function cathodes. Proc. Natl Acad. Sci. USA 105, 12730–12735 (2008).

    CAS  Article  Google Scholar 

  19. 19

    Hardy, L. C. & Shriver, D. F. Preparation and electrical response of solid polymer electrolytes with only one mobile species. J. Am. Chem. Soc. 107, 3823–3828 (1985).

    CAS  Article  Google Scholar 

  20. 20

    Ratner, M. A. & Shriver, D. F. Ion-transport in solvent-free polymers. Chem. Rev. 88, 109–124 (1988).

    CAS  Article  Google Scholar 

  21. 21

    Zhang, Q. S. et al. Highly efficient electroluminescence from green-light-emitting electrochemical cells based on Cu–I complexes. Adv. Funct. Mater. 16, 1203–1208 (2006).

    CAS  Article  Google Scholar 

  22. 22

    Hoven, C. et al. Ion motion in conjugated polyelectrolyte electron transporting layers. J. Am. Chem. Soc. 129, 10976–10977 (2007).

    CAS  Article  Google Scholar 

  23. 23

    Bernards, D. A., Flores-Torres, S., Abruna, H. D. & Malliaras, G. G. Observation of electroluminescence and photovoltaic response in ionic junctions. Science 313, 1416–1419 (2006).

    CAS  Article  Google Scholar 

  24. 24

    Cheng, C. H. W., Boettcher, S. W., Johnston, D. H. & Lonergan, M. C. Unidirectional current in a polyacetylene hetero-ionic junction. J. Am. Chem. Soc. 126, 8666–8667 (2004).

    CAS  Article  Google Scholar 

Download references


We gratefully acknowledge the National Science Foundation (DMR Program) and the Institute for Multiscale Materials Studies for financial support. We also thank T. Q. Nguyen and D. Smith for helpful discussions.

Author information




C.V.H., M.E. and G.C.B. designed the experiments, analysed the data and wrote the paper. C.V.H and M.E. carried out the experiments. M.E. and G.C.B. designed the polymers. H.W., M.E., L.G. and D.W. synthesized the polymers.

Corresponding author

Correspondence to Guillermo C. Bazan.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 537 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Hoven, C., Wang, H., Elbing, M. et al. Chemically fixed p–n heterojunctions for polymer electronics by means of covalent B–F bond formation. Nature Mater 9, 249–252 (2010).

Download citation

Further reading


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing