Piezoresistive semi-transparent flexible sensors by bithiophene fulleropyrrolidine thin films

Piezoresistive sensors are considered among the fundamental components of the future wearable electronic devices, given their potential applications in artificial skin, motion capture and personalized medicine.[1-5] Here, we present a cost-effective, viable fabrication approach to realize piezoresistive sensors using a novel polymeric biotiophene fulleropyrrolidine system (bis-C60Bi) synthesized on flexible ITO/PET supports by electrochemical chronoamperometry. By applying an anodic potential (1.5 V) to a solution containing the monomer, it is possible to obtain a homogeneous semi-transparent thin film on the ITO/PET surface (see Figure). AFM, XPS, UV-vis have been employed to characterize the morphology and chemical composition of the new synthesized polymeric thin films, confirming the chemical structure and showing a nanoscale surface roughness of about 25 nm. The resulting polymer-based device shows good resistance variation on bending in the semi-static regime, outperforming current ITO/PET resistive sensors [6] and well matching commercial devices based on opaque amorphous carbon materials.[7] The durability of the sensor has been validated over almost one hundred cycles. This new class of polymeric piezoresistive sensors may open new applications in the field of kinematic acquisition or of sensor monitoring, with several potential applications as well as in medicine, robotics and physiotherapy. Bibliography 1 M. Ricci, G. Di Lazzaro, A. Pisani, N. B. Mercuri, F. Giannini, G. Saggio, IEEE Journal of Biomedical and Health Informatics, 2019, doi: 10.1109/JBHI.2019.2903627 2 G. Arrabito, V. Errico, Z. Zhang, W. Han, C. Falconi, Nano Energy, 2018, 46, 54. doi: 10.1016/j.nanoen.2018.01.029 3 G. Saggio, G. Orengo, A. Pallotti, V. Errico, M. Ricci, IEEE International Symposium on Medical Measurements and Applications (MeMeA), 2018, doi: 10.1109/MeMeA.2018.8438767 4 N. Jasoon, M.D. Ho, W. Cheng, J. Mater. Chem. C, 2017, 5, 5845. 5 G. Saggio ; G. Orengo ; A. Pallotti ; V. Errico ; M. Ricci, International Symposium on Networks, Computers and Communications (ISNCC) 2018 doi: 10.1109/ISNCC.2018.8531054 6 T. Lee, Y. W. Choi, G. Lee, P. V. Pikhita, D. Kang, S.M. Kim and M. Choi, J. Mater. Chem. C, 2016, 4, 9947. 7 G. Saggio, G. Orengo, Sensors and Actuators A, 2018, 273, 221.