A flexible contact and non-contact bifunctional intelligent sensing system based on a triboelectric nanogenerator

Conventional electronic skin (e-skin) that combines non-contact sensing with contact sensing relies on the combination of sensors, greatly hindering its application in human-machine interface (HMI). Herein, a triboelectric nanogenerator based on Ecoflex/PEDOT:PSS (EP-TENG) is proposed to achieve both contact and non-contact sensing. The EP-TENG comprises an Ecoflex/PEDOT:PSS triboelectric layer with a cicada wing-inspired microstructure and MXene electrode with superior conductivity. Benefit from the high specific surface area brought by cicada wing micropillars and the charge retention ability of PEDOT:PSS, The EP-TENG has good non-contact sensing capability within a range of 80   mm and also has excellent performance in contact mode, with an open circuit voltage (V oc ) of 124   V and a power density of 75.3   mW/m². Importantly, our work develops a dual-mode control strategy that combines non-contact gesture recognition and contact-based interactive control. We demonstrate the EP-TENG dual-mode control through a Tetris unlocking system, which makes up for the lack of precise control in the non-contact mode and shows its important application potential in multi-mode human-computer interaction in complex scenarios in the future.