“…To achieve high-performance FRTC, considerable efforts have been made in optimization of the materials and device configurations. First, various active materials such as graphene, carbon black (CB), carbon fiber, carbon nanotube (CNT) and multi-walled CNT (MWCNT) ( Liu et al, 2012 ; Guo et al, 2014 ; Tian et al, 2015 ; Wang et al, 2017 ; Wu et al, 2019 ) have been introduced into FRTC as the conductive fillers due to their high conductivity, low cost, and high stability ( Kun et al, 2020 ; Abdelmoughni et al, 2020 ; Jea Sang et al, 2020 ; Su et al, 2020 ; Jian et al, 2020 ; Ye et al, 2020 ; Zamri et al, 2015 ; J Mittemeijer, 2011 ; Nosbi et al, 2010 ; Chen et al, 2017a ; Zhang et al, 2017a ; Ying et al, 2011 ; Wang et al, 2017 ). Second, for obtaining highly flexible and stretchable devices, polymers including polydimethylsiloxane (PDMS) ( Shih et al, 2010 ; Sibinski et al, 2010 ; Zhao et al, 2018a ), silicon rubber, poly (vinylidene fluoride) (PVDF), polymethyl methacrylate (PMMA) and poly (3,4-ethylenedioxythiophene-poly (styrenesulfonate) (PEDOT: PSS) ( Nakata and Arie, 2017 ; Huang et al, 2018 ; Shen et al, 2018 ; Chen et al, 2018 ; Bang et al, 2019 ) have been widely investigated in FRTC ( Shih et al, 2010 ; Sibinski et al, 2010 ; Liu et al, 2012 ; Guo et al, 2014 ; Tian et al, 2015 ; Nakata and Arie, 2017 ; Wang et al, 2017 ; Zhao et al, 2018a ; Huang et al, 2018 ; Shen et al, 2018 ; Chen et al, 2018 ; Bang et al, 2019 ; Wu et al, 2019 ).…”