Boosting Sensing Performance of Vacancy-Containing Vertically Aligned MoS2 Using rGO Particles

A design of an advanced sensing material, such as MoS
₂
, is imperative to enhance the sensing performance of a sensor. Because their usage alone for developing a practical sensor is impeditive owing to low gas response and slow response/recovery kinetics. Here, we report a high-performance NO
₂
gas sensor using a hybrid of temperature-assisted sulfur vacancy within the edge-oriented vertically aligned MoS
₂
(Sv-MoS
₂
) and crumpled reduced graphene oxide (rGO) particles. Interestingly, the Sv-MoS
₂
functionalized by optimized rGO concentration exhibited a significant enhancement of response to NO
₂
(approximately three times higher than that of pristine vertically aligned MoS
₂
) with fast response (<; 1 min) and complete recovery. Such a large improvement in the sensing performance could be attributed to controlled electrical/chemical sensitization level of MoS
₂
through controllable vacancy and interface engineering. The vacancy engineering offers abundant active sites through creating sulfur vacancy in additionally rich edge active sites of vertically oriented MoS
₂
for more electronic interaction with gas molecules. While interfacing of p-type rGO particles with n-type MoS
₂
leads to multiple out-of-plane vertical nano-heterojunctions as a sensitizing configuration for boosting the performance of the sensor. This paper opens up a new approach towards improving the sensing activity of a 2D material via a synergistic vacancy and interface engineering.