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

TLDR

Large‑area, ultrathin tactile sensors are essential for wearable electronics, but passive designs suffer from high crosstalk that limits performance; active‑matrix sensors could overcome this but require high‑performance TFT arrays. The authors fabricated a MoS₂‑based back‑plane circuitry and strain sensor by sandwiching MoS₂ between high‑k Al₂O₃ dielectric layers to achieve high reliability and performance. This approach yields an 8 × 8 all‑MoS₂ active‑matrix tactile sensor with a 1–120 kPa range, 0.011 kPa⁻¹ sensitivity, 180 ms response, excellent linearity, and demonstrated multitouch, stylus tracking, and shape detection by hand grasp.

Abstract

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 (ΔR/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.