Flexible Tactile\nSensors with Gradient Conformal Dome\nStructures

The trade-off between high sensitivity and wide detection\nrange\nremains a challenge for flexible capacitive pressure sensors. Gradient\nstructure can provide continuous deformation and lead to a wide sensing\nrange. However, it simultaneously augments the distance between two\nelectrodes, which diminishes the variation in the relative distance\nand results in a decreased sensitivity. Herein, a conformal design\nis introduced into the gradient structure to construct a flexible\ncapacitive pressure sensor. The gradient conformal dome structure\nis fabricated by a simple reverse dome adsorption process. Taking\nadvantage of the progressive deformation behavior of the gradient\ndielectric, and the significant improvement of relative distance variation\nbetween two electrodes from the conformal design, the sensor achieves\na sensitivity of 0.214 kPa<sup>–1</sup> in an ultrabroad linear\nrange up to 200 kPa. It maintains high-pressure resolution under the\npreload of 10 and 100 kPa. Benefiting from the rapid response and\nexcellent repeatability, the sensor can be used for physiological\nmonitor and human motion detection, including arterial pulse, joint\nbending, and motion state. The gradient conformal design strategy\nmay pave a promising avenue to develop pressure sensors with high\nsensitivity and wide linear range.