Low Operating Voltage Metal‐Oxide Thin‐Film Transistor for Portable Physiological Temperature Sensing

Abstract Physiological temperature sensors are essential for accurately tracking body temperature, yet human body temperature sensors with both high precision and linearity have not been widely reported. In this work, a solution‐processed, low‐voltage TFT‐based temperature sensor is developed using LiInSnO ₄ ionic gate dielectric with ZnO (or SnO ₂ ) as semiconductors. Alongside excellent TFT performance, the devices exhibit high precision and sensitivity of 0.7 µA °C ⁻¹ during heating and 0.6 µA °C ⁻¹ during cooling for ZnO‐based TFT, while SnO ₂ ‐based TFT shows slightly higher sensitivity with 1.1 µA °C ⁻¹ in heating and 1.2 µA °C ⁻¹ in cooling. Additionally, the voltage sensitivity remains consistent at 0.01 V °C ⁻¹ for both TFTs under all conditions. Furthermore, the devices demonstrate high linearity in temperature coefficient of current (TCC) and temperature coefficient of voltage (TCV) curves, confirming their capability for accurate temperature measurement.