N dopants triggered new active sites and fast charge transfer in MoS2 nanosheets for full Response-Recovery NO2 detection at room temperature

The slow response and incomplete recovery are primary bottlenecks for the sensing performance of 2D transition metal dichalcogenides (TMDs) at room temperature, which hinders their development for state-of-the-art gas sensors. Herein, we engineered N doped p-type MoS2 against its native n-type propensity to enable a rapid room-temperature response/recovery detection of NO2. Compared to pristine n-type MoS2 showing typical slow response and no recovery (1544 s/-), the prepared N-doped MoS2 sensor exhibits a fast response/recovery (22/109 s) toward 10 ppm NO2 at room temperature. In addition, the N dopants endow MoS2 with a sensing response of 28% to 10 ppm NO2, ppb-level of detection limit (125 ppb), excellent selectivity, good repeatability, and humidity resistance. We underline the fast response/recovery mechanism of N-doped MoS2 to be the N dopants triggered synergistic effect of new active sites and fast charge transfer based on density functional theory calculation and Hall-Effect measurement. We hope this result may shed a new light on the development of TMDs-based sensing materials aiming at improving their room-temperature response/recovery performance.

Automated summary

The engineered N-doped MoS2 sensor shows rapid room-temperature response and recovery for NO2 detection, with high sensitivity, low detection limit, excellent selectivity, repeatability, and humidity resistance. The fast response and recovery mechanism is triggered by the synergistic effect of N dopants creating new active sites and facilitating fast charge transfer. This result could potentially advance the development of TMDs-based sensing materials for improved room-temperature performance.