Sensing mechanism of acetone adsorption on charged ZnO and ZnSe surfaces: Insights from DFT calculations

Abstract

Acetone sensing is meaningful for human health, food safety and animal safety. In this work, the sensing mechanism of acetone adsorption on charged II-VI semiconductor (ZnO and ZnSe) is systematically investigated by density functional theoretical calculations. It is found that compared with charged ZnO surfaces, charged ZnSe surfaces possess stronger acetone adsorption strength. Both positive and negative surface charges could enhance acetone sensing of ZnO surface while only negative surface charges could enhance acetone sensing on ZnSe surface. The appropriate charge states of ZnO or ZnSe are of significance to realize fast recovery. Because acetone desorption process could be endothermic with added energy under some charge states. Additionally, the acetone selectivity of sensing surface could be controlled by surface charge states. Moreover, acetone sensing could be effectively improved by the synergistic effect of surface charge states and ZnSe/ZnO heterostructures. Our results extend the knowledge into the acetone sensing mechanisms induced by surface charge states.