Influence of the surface decoration of phosphorene with Ag nanoclusters on gas sensing properties

Abstract

Easy aggregation of metal nanoclusters and less selectivity and sensitivity of 2D materials always limit their further applications in the design of commercial gas-sensors. To overcome these deficiencies, we propose a combined system of Ag nanoclusters and 2D phosphorene for the design of new gas nanosensors based on the first-principles calculation. The AgN nanoclusters (1 ≤ N ≤ 13) can reduce the degradation of phosphorene and present a variety of structures with different active adsorption sties exposed, which can greatly increase the selectivity and sensitivity of the system to the adsorbed molecules. The sensitivity of phosphorene can be improved by the decoration of Ag atom due to the participation of valence electrons of Ag atom coming from the s and d electronic orbitals, which can modulate the charge distribution between the adsorbed molecules and the phosphorene. Moreover, the work function changes significantly when gas molecules adsorbed on Ag1-phosphorene, especially it increases by 30.5% for NO2 molecule. The I-V curves show that NO2 adsorption requires the higher bias voltage than Ag1-phosphorene. Our theoretic results serve to deepen our insights into surface modification of phosphorene via the decoration of noble metal Ag and to provide a novel pathway to design high performance phosphorene-based gas sensors.