My group has engineered nano and 2D materials into soft sensors. One example is a porous nanocomposite as the functional material for wide-range, high-sensitivity capacitive pressure sensors (c) (manuscript is under revision with Adv. Mater.). Another example is the world’s first submicron-thick e-tattoo based on large-area monolayer graphene grown through chemical vapor deposition (CVD) (d) 9,10. It has been applied as ultra-conformable and hence low-contact-impedance dry electrodes for high-fidelity, long-term electrophysiological sensing.9 It has also been used as a mechanically and optically imperceptible electrooculography (EOG) sensor placed on human face for the remote control of a drome purely through eyeball rotation.10 Our groundbreaking work of ultra-conformable graphene e-tattoo (GET) has sparked numerous developments of skin-conformable electrodes based on gold nanomesh and other 2D materials. We have carefully characterized the stretchability of CVD monolayer graphene supported by ultrathin polymer substrate and found that it has much better mechanical robustness than nanocrystalline gold thin films (e).11 In collaboration with Prof. Edward Yu at UT, we have also investigated the piezoelectric and flexoelectric properties of 2D materials using piezoresponse force microscopy (PFM) 12,13.
9 Ameri, S.K., Ho, R., Jang, H.W., Tao, L., Wang, Y.H., Wang, L., Schnyer, D.M., Akinwande, D., and Lu, N.: ‘Graphene Electronic Tattoo Sensors’, Acs Nano, 2017, 11, (8), pp. 7634-7641
10 Ameri, S.K., Kim, M., Kuang, I.A., Perera, W.K., Alshiekh, M., Jeong, H., Topcu, U., Akinwande, D., and Lu, N.: ‘Imperceptible Electrooculography Graphene Sensor System for Human-Robot Interface ’, npj 2D Materials and Applications, 2018, 2, pp. 19
11 Jang, H., Dai, Z., Ha, K.-H., Ameri, S.K., and Lu, N.: ‘Stretchability of PMMA-supported CVD graphene and of its electrical contacts’, Semiconduct Semimet, 2019, 7, (1)
12 Brennan, C.J., Ghosh, R., Koul, K., Banerjee, S.K., Lu, N.S., and Yu, E.T.: ‘Out-of-Plane Electromechanical Response of Monolayer Molybdenum Disulfide Measured by Piezoresponse Force Microscopy’, Nano Lett, 2017, 17, (9), pp. 5464-5471
13 Brennan, C.J., Koul, K., Lu, N., and Yu, E.T.: ‘Out-of-Plane Electromechanical Coupling in Transition Metal Dichalcogenides ’, Appl Phys Lett, 2020, 116, pp. 053101