SnSe2/Ag2Se heterostructures with an accumulation layer for rapid and sensitive detection of NO2

Tin selenide (SnSe2) is a potential sensing material for NO2 detection owing to its large specific surface area and narrow bandgap. However, sensors based on pristine SnSe2 still suffer from the disadvantages of a low response value and long response/recovery time at room temperature. Herein, SnSe2/Ag2Se n-n heterojunctions with an accumulation layer are fabricated via a one-step hydrothermal method. The amounts of the SnSe2/Ag2Se heterojunctions are effectively controlled by adjusting the Ag source content. The optimized SnSe2/Ag2Se sensor shows a response value of 12 to 5 ppm NO2 at room temperature, which is 4 times larger than that of the pristine SnSe2. The SnSe2/Ag2Se sensor exhibits a significantly shorter response/recovery time (21/103 s) than most of the reported two-dimensional materials at room temperature. This excellent performance is attributed to the enhanced electron transfer and the increased adsorption sites. In addition, the SnSe2/Ag2Se sensor exhibits good selectivity, which makes it highly suitable for practical applications.

Automated summary

SnSe2/Ag2Se n-n heterojunctions with an accumulation layer are fabricated via hydrothermal method, which exhibit improved response value and shorter response/recovery time compared to pristine SnSe2 sensor. The SnSe2/Ag2Se sensor shows good selectivity for NO2 detection, making it suitable for practical applications.