Tellurene based chemical sensor†
Chemiresistive sensor devices using two-dimensional (2D) materials have been extensively studied. However, so far no single material has all the desirable attributes. For example, graphene and MXenes lack a band gap, transition metal dichalcogenides (such as MoS2) lack high sensitivity, while phosphorene exhibits poor air-stability. Here we report that tellurene, a new emergent single-element 2D material, excels as a sensor for NO2 detection. Devices based on tellurene exhibit a detection limit of ∼25 ppb, large detection range (from 25 ppb to 5 ppm), baseline noise as low as ∼0.5%, and excellent “selectivity” to NO2 even in the presence of cross-contaminants such as CO, SO2, H2S, acetone and ethanol. Density functional theory calculations indicate that large adsorption energy and intense charge redistribution are the reasons for the high sensitivity and selectivity of tellurene for NO2 detection. Further, we find that “heat-pulsing” enables fast sensor response and recovery time, without damaging the tellurene sheets. Most importantly, tellurene exhibits outstanding air-stability, making it a promising candidate for next-generation chemical sensors.