Metallic Ti3C2Tx MXene Gas Sensors with Ultrahigh Signal-to-Noise Ratio

Achieving high sensitivity in solid-state gas sensors can allow the precise detection of chemical agents. In particular, detection of volatile organic compounds (VOCs) at the parts per billion level is critical for the early diagnosis of diseases. To obtain high sensitivity, two requirements need to be simultaneously satisfied: low electrical noise and strong signal, which existing sensor materials cannot meet. Sensitive gas detection is becoming increasingly important in detecting toxic gases in air, pollution monitoring, and therapeutic diagnosis by breath analysis. In particular, detection of VOCs in exhaled breath below parts per million (ppm) level is critical for the early diagnosis of illnesses. In order to achieve high sensitivity, a wide range of channel materials has been employed for resistive sensors, which can be mainly categorized into semiconducting and conducting channels. Metal oxide semiconductors, in which the atmospheredependent surface conductivity governs the sensing mechanism, are representative semiconducting channel materials.