Toward high selectivity of sensor arrays: Enhanced adsorption interaction and selectivity of gas detection (N2, O2, NO, CO, CO2, NO2, SO2, AlH3, NH3, and PH3) on transition metal dichalcogenides (MoS2, MoSe2, and MoTe2)

Resistive gas sensors are essential for monitoring air quality, ensuring industrial safety, and controlling automotive emissions. However, conventional materials used for sensing layers often suffer from poor selectivity and require elevated operating temperatures, limiting their effectiveness. This study introduces a novel approach to address these challenges by utilizing the intrinsic physicochemical properties of Mo-bearing transition-metal dichalcogenides (TMDs). The findings reveal that variable charge availability on TMD surfaces leads to highly selective adsorption enhancements, resulting in significant differences in the TMD responses to various molecules, even at room temperature. This results in an exceptional relative sensitivity of the TMD monolayers, which in the case of combustion products exceeds what is feasible under the same conditions by conventional sensing materials such as ZnO and TiO2 by three orders of magnitude. Such an unprecedented variation in responses results in distinct sensing profiles. This enables effective cross-referencing of responses, offering significant benefits for sensor arrays. Consequently, even in relatively simple setups, TMD-based devices have the potential to prevent false-positive signals and even enable the determination of the composition of gas mixtures, which, if utilized, could revolutionize the field of gas monitoring with innovative lab-on-a-chip solutions.