Discriminative Analysis of NO Gases by Two-Dimensional Violet Phosphorus Field-Effect Transistors.

Two-dimensional violet phosphorus (VP) has emerged as a new sensing material in various sensing applications due to its unique electrical properties and high stability among allotropes of phosphorus. Currently, the research of the VP-based analysis method is at the early stage. In this work, a VP nanosheet-based field-effect transistor (FET) sensor is reported for the detection of NO and NO gases with extraordinary sensing performance. This sensor can achieve excellent sensitivity of up to ∼50% current change/ppm and a low detection limit of 5.9 ppb and enables the NO analysis in various mixed gases. Moreover, this sensor can effectively distinguish between NO and NO gases, which is a big challenge for current FET or chemiresistor gas sensors. The different sensing behaviors of the VP sensor to NO and NO gases have been investigated, and the mechanism study shows that the adsorption energy, bond length of the gas molecule on the VP surface, and the decomposition of NO led to the differential responses. This work is one of the pioneer studies of VP gas sensors and presents a new sensing method for the discriminative analysis of NO and NO for greenhouse gas emission monitoring and air quality control.