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

Nature Materials volume 9, pages 249–252 (2010)Cite this article

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Abstract

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.

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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: L–J–V characteristics of fixed p–n junction device.

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Acknowledgements

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.

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Authors and Affiliations

  1. Department of Materials, University of California, Santa Barbara, California 93106, USA

    Corey V. Hoven & Guillermo C. Bazan

  2. Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA

    Huiping Wang, Mark Elbing, Logan Garner & Guillermo C. Bazan

  3. State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, China

    Huiping Wang

  4. Inorganic & Structural Chemistry, University Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany

    Daniel Winkelhaus

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  1. Corey V. Hoven
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Contributions

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.

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Correspondence to Guillermo C. Bazan.

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The authors declare no competing financial interests.

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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). https://doi.org/10.1038/nmat2623

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