Zinc oxide–black phosphorus composites for ultrasensitive nitrogen dioxide sensing

Abstract

Multi-layer black phosphorus (m-BP) has been successfully incorporated in zinc oxide (ZnO) hollow spheres, thus forming hetero-structured ZnO–BP composites; a study performed on their properties reveals that the BP environmental stability can be significantly enhanced by the introduction of ZnO, and the sensors based on ZnO–BP composites exhibit high response, fast response behavior, outstanding selectivity, and ultralow detection limit of 1 ppb towards NO₂ gas molecules. The ultrasensitive sensing performance is suggested to be due to the large surface area, excellent carrier mobility, and enhanced charge transfer of ZnO–BP in the presence of BP. Moreover, the mechanism of NO₂ sensing with ZnO–BP is confirmed by the calculations obtained from the first-principle studies.