Skin-like pressure and strain sensors based on transparent elastic films of carbon nanotubes

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Transparent, elastic conductors are essential components of electronic and optoelectronic devices that facilitate human interaction and biofeedback, such as interactive electronics1, implantable medical devices2 and robotic systems with human-like sensing capabilities3. The availability of conducting thin films with these properties could lead to the development of skin-like sensors4 that stretch reversibly, sense pressure (not just touch), bend into hairpin turns, integrate with collapsible, stretchable and mechanically robust displays5 and solar cells6, and also wrap around non-planar and biological7,8,9 surfaces such as skin10 and organs11, without wrinkling. We report transparent, conducting spray-deposited films of single-walled carbon nanotubes that can be rendered stretchable by applying strain along each axis, and then releasing this strain. This process produces spring-like structures in the nanotubes that accommodate strains of up to 150% and demonstrate conductivities as high as 2,200 S cm−1 in the stretched state. We also use the nanotube films as electrodes in arrays of transparent, stretchable capacitors, which behave as pressure and strain sensors.

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Figure 1: Effects of applied strain on films of spray-coated carbon nanotubes on PDMS substrates.
Figure 2: Evolution of morphology of films of carbon nanotubes with stretching.
Figure 3: Use of stretchable nanotube films in compressible capacitors that can sense pressure and strain.
Figure 4: Summary of processes used to fabricate arrays of transparent, compressible, capacitive sensors.
Figure 5: Images showing the characteristics of a 64-pixel array of compressible pressure sensors.

Change history

  • 28 October 2011

    In the version of this Letter originally published online, the colour scale in Fig. 5c should have read 'x10−2'. This has been corrected in all versions of the Letter.


  1. 1

    LeMieux, M. C. & Bao, Z. N. Flexible electronics: stretching our imagination. Nature Nanotech. 3, 585–586 (2008).

  2. 2

    Kim, B. Y. S., Rutka, J. T. & Chan, W. C. W. Current concepts: nanomedicine. New Engl. J. Med. 363, 2434–2443 (2010).

  3. 3

    Ilievski, F., Mazzeo, A. D., Shepherd, R. F., Chen, X. & Whitesides, G. M. Soft sobotics for chemists. Angew. Chem. Int. Ed. 50, 1890–1895 (2011).

  4. 4

    Cotton, D. P. J., Graz, I. M. & Lacour, S. P. A multifunctional capacitive sensor for stretchable electronic skins. IEEE Sens. J. 9, 2008–2009 (2009).

  5. 5

    Sekitani, T. et al. Stretchable active-matrix organic light-emitting diode display using printable elastic conductors. Nature Mater. 8, 494–499 (2009).

  6. 6

    Lipomi, D. J., Tee, B. C.-K., Vosgueritchian, M. & Bao, Z. N. Stretchable organic solar cells. Adv. Mater. 23, 1771–1775 (2011).

  7. 7

    Ko, H. C. et al. A hemispherical electronic eye camera based on compressible silicon optoelectronics. Nature 454, 748–753 (2008).

  8. 8

    Kim, D. H. et al. Dissolvable films of silk fibroin for ultrathin conformal bio-integrated electronics. Nature Mater. 9, 511–517 (2010).

  9. 9

    Kim, R. H. et al. Waterproof AlInGaP optoelectronics on stretchable substrates with applications in biomedicine and robotics. Nature Mater. 9, 929–937 (2010).

  10. 10

    Kim, D. H. et al. Epidermal electronics. Science 333, 838–843 (2011).

  11. 11

    Viventi, J. et al. A conformal, bio-interfaced class of silicon electronics for mapping cardiac electrophysiology. Sci. Transl. Med. 2, 24ra22 (2010).

  12. 12

    Graz, I. M., Cotton, D. P. J. & Lacour, S. P. Extended cyclic uniaxial loading of stretchable gold thin-films on elastomeric substrates. Appl. Phys. Lett. 98, 071902 (2009).

  13. 13

    Jones, J., Lacour, S. P., Wagner, S. & Suo, Z. G. Stretchable wavy metal interconnects. J. Vac. Sci. Technol. A 22, 1723–1725 (2004).

  14. 14

    Tahk, D., Lee, H. H. & Khang, D. Y. Elastic moduli of organic electronic materials by the buckling method. Macromolecules 42, 7079–7083 (2009).

  15. 15

    Zhang, Y. Y. et al. Polymer-embedded carbon nanotube ribbons for stretchable conductors. Adv. Mater. 22, 3027–3031 (2010).

  16. 16

    Kim, K. S. et al. Large-scale pattern growth of graphene films for stretchable transparent electrodes. Nature 457, 706–710 (2009).

  17. 17

    Avouris, P. Carbon nanotube electronics and photonics. Phys. Today 62, 34–40 (2009).

  18. 18

    Bae, S. et al. Roll-to-roll production of 30-inch graphene films for transparent electrodes. Nature Nanotech. 5, 574–578 (2010).

  19. 19

    Feng, C. et al. Flexible, stretchable, transparent conducting films made from superaligned carbon nanotubes. Adv. Funct. Mater. 20, 885–891 (2010).

  20. 20

    Hu, L. B., Yuan, W., Brochu, P., Gruner, G. & Pei, Q. B. Highly stretchable, conductive, and transparent nanotube thin films. Appl. Phys. Lett. 94, 161108 (2009).

  21. 21

    Yu, Z. B., Niu, X. F., Liu, Z. & Pei, Q. B. Intrinsically stretchable polymer light-emitting devices using carbon nanotube-polymer composite electrodes. Adv. Mater. 23, 3989–3994 (2011).

  22. 22

    Chun, K. Y. et al. Highly conductive, printable and stretchable composite films of carbon nanotubes and silver. Nature Nanotech. 5, 853–857 (2010).

  23. 23

    Yu, C. J., Masarapu, C., Rong, J. P., Wei, B. Q. & Jiang, H. Q. Stretchable supercapacitors based on buckled single-walled carbon nanotube macrofilms. Adv. Mater. 21, 4793–4797 (2009).

  24. 24

    Bekyarova, E. et al. Electronic properties of single-walled carbon nanotube networks. J. Am. Chem. Soc 127, 5990–5995 (2005).

  25. 25

    Hu, L. B., Hecht, D. S. & Gruner, G. Carbon nanotube thin films: fabrication, properties, and applications. Chem. Rev. 110, 5790–5844 (2010).

  26. 26

    Nosho, Y., Ohno, Y., Kishimoto, S. & Mizutani, T. The effects of chemical doping with F(4)TCNQ in carbon nanotube field-effect transistors studied by the transmission-line-model technique. Nanotechnology 18, 415202 (2007).

  27. 27

    Khang, D. Y. et al. Molecular scale buckling mechanics in individual aligned single-wall carbon nanotubes on elastomeric substrates. Nano Lett. 8, 124–130 (2008).

  28. 28

    Kubo, M. et al. Stretchable microfluidic radiofrequency antennas. Adv. Mater. 22, 2749–2752 (2010).

  29. 29

    Cao, Q. & Rogers, J. A. Ultrathin films of single-walled carbon nanotubes for electronics and sensors: a review of fundamental and applied aspects. Adv. Mater. 21, 29–53 (2009).

  30. 30

    Jackman, R. J., Duffy, D. C., Cherniavskaya, O. & Whitesides, G. M. Using elastomeric membranes as dry resists and for dry lift-off. Langmuir 15, 2973–2984 (1999).

  31. 31

    So, J. H. et al. Reversibly deformable and mechanically tunable fluidic antennas. Adv. Funct. Mater. 19, 3632–3637 (2009).

  32. 32

    Dickey, M. D. et al. Eutectic gallium-indium (EGaIn): a liquid metal alloy for the formation of stable structures in microchannels at room temperature. Adv. Funct. Mater. 18, 1097–1104 (2008).

  33. 33

    Mannsfeld, S. C. B. et al. Highly sensitive flexible pressure sensors with microstructured rubber dielectric layers. Nature Mater. 9, 859–864 (2010).

  34. 34

    Takei, K. et al. Nanowire active-matrix circuitry for low-voltage macroscale artificial skin. Nature Mater. 9, 821–826 (2010).

  35. 35

    Someya, T. et al. Conformable, flexible, large-area networks of pressure and thermal sensors with organic transistor active matrixes. Proc. Natl Acad. Sci. USA 102, 12321–12325 (2005).

  36. 36

    Sokolov, A. N., Tee, B. C.-K., Bettinger, C. J., Tok, J. B.-H. & Bao, Z. N. Chemical and engineering approaches to enable organic field-effect transistors for electronic skin applications. Acc. Chem. Res. (in the press).

  37. 37

    Roberts, M. E., Sokolov, A. N. & Bao, Z. N. Material and device considerations for organic thin-film transistor sensors. J. Mater. Chem. 19, 3351–3363 (2009).

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This work was supported by a US Intelligence Community Postdoctoral Fellowship (to D.J.L.) and the Stanford Global Climate and Energy Program. B.C-K.T. was supported by the Singapore National Science Scholarship from the Agency for Science Technology and Research (A*STAR). The authors thank V. Ballarotto for helpful discussions and J.A. Bolander for writing code for the apparatus used for electromechanical measurements.

Author information

D.J.L. and Z.B. conceived the project. D.J.L., M.V. and B.C-K.T. performed and designed the experiments. S.L.H. prepared the materials and developed the conditions used to dope the nanotube films. J.A.L. deposited additional nanotube films. J.A.L. and C.H.F. performed experiments on resistance versus strain. D.J.L., B.C-K.T., M.V., S.L.H. and Z.B. analysed the data. D.J.L. wrote the paper. All authors discussed the results and commented on the manuscript.

Correspondence to Zhenan Bao.

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Lipomi, D., Vosgueritchian, M., Tee, B. et al. Skin-like pressure and strain sensors based on transparent elastic films of carbon nanotubes. Nature Nanotech 6, 788–792 (2011) doi:10.1038/nnano.2011.184

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