A humidity-tolerant NO 2 sensor based on Ag 3 PO 4 –SnSe 2 heterostructures

Gas sensing under harsh conditions, like humid environments, is highly required in the development of the Internet of Things. However, conventional gas sensors based on metal oxide semiconductors often suffer from a deterioration in sensing performance in a highly humid environment. Herein, Ag 3 PO 4 –SnSe 2 heterostructures were constructed as a NO 2 sensing material to work under highly humid environments at room temperature. The Ag 3 PO 4 –SnSe 2 sensor exhibited an increased response with the increase in relative humidity. The chemical inertness to H 2 O molecules of SnSe 2 and the high affinity to H 2 O molecules of Ag 3 PO 4 played vital roles in improving the anti-humidity ability. Additionally, the sensor also demonstrated a high sensing response (6.8) to 5 ppm NO 2 and a short response/recovery time (31/108 s) at room temperature. This study provides a new method to design advanced gas sensors with a high anti-humidity ability for room temperature NO 2 detection.