Chemical vapor sensing with CVD-grown monolayer MoSe2 using photoluminescence modulation

Monolayer two-dimensional transition metal dichalcogenides (TMDs) such as MoSe2 are promising materials for chemical vapor sensing applications due to their unique monolayer structure, ease of fabrication, low cost, selectivity, sensitivity, and speed of response. To date, most chemical vapor and gas sensors that use TMDs are based on chemiresistive device properties. However, recent studies indicate that the optical properties, in particular the photoluminescence (PL), could be used to sense vapors as well. In this study, we examine the PL of MoSe2 while it is exposed to triethylamine, a strong electron donor and chemically relevant to nerve gas and explosive sensing. We observe a fast and significant decrease in the PL by as much as 75% during exposure. The PL begins to recover as soon as the vapor is switched off, indicating fast adsorption/desorption of the analyte. We analyze the data in terms of possible applications to chemical vapor sensing.