All MoS₂-Based Large Area, Skin-Attachable Active-Matrix Tactile Sensor

Large-area, ultrathin flexible tactile sensors with conformal adherence are becoming crucial for advances in wearable electronics, electronic skins and biorobotics. However, normal passive tactile sensors suffer from high crosstalk, resulting in inaccurate sensing, which consequently limits their use in such advanced applications. Active-matrix-driven tactile sensors could potentially overcome such hurdles, but it demands the high performance and reliable operations of the thin-film-transistor array that could efficiently control integrated pressure gauges. Herein, we utilized the benefit of the semiconducting and mechanical excellence of MoS₂ and placed it between high- k Al₂O₃ dielectric sandwich layers to achieve the high and reliable performance of MoS₂-based back-plane circuitry and strain sensor. This strategical combination reduces the fabrication complexity and enables the demonstration of an all MoS₂-based large area (8 × 8 array) active-matrix tactile sensor offering a wide sensing range (1-120 kPa), sensitivity value (Δ R/ R₀: 0.011 kPa^-1), and a response time (180 ms) with excellent linearity. In addition, it showed potential in sensing multitouch accurately, tracking a stylus trajectory, and detecting the shape of an external object by grasping it using the palm of the human hand.