Au – MoS2 nanoflowers sensors on interdigitated electrode for monitoring human respiration

Abstract

Abstract Respiratory humidity sensors are essential for monitoring breath conditions in a variety of applications such as respiratory disease diagnosis, sleep apnea screening, and personalized medicine. With the increasing prevalence of respiratory diseases, such as asthma, chronic obstructive pulmonary disease (COPD), and sleep apnea, they have become essential tools for healthcare professionals, researchers and individuals. However, existing humidity sensors often suffer from poor sensitivity, slow response, and limited flexibility. In this paper, we report a novel Au – MoS2 respiratory humidity sensor that exhibits high resistivity, fast response, and excellent flexibility. The sensor is fabricated by drop casting a thin layer of Au decorated MoS2 on copper interdigitated electrodes (fabricated using copper clad PCB). The increase in the intensity of the peak was observed in Au – MoS2 hybrids in comparison to MoS2 analyzed using micro–Raman Spectroscopy. Using scanning electron microscopy (SEM), the morphology of MoS2 was observed, confirming its flower like structure. The Au nanoparticles were detected on the edges of MoS2, confirmed by transmission electron microscope (TEM).
The interfacial electronic interaction suggests that there is the formation of Schottky barrier between Au and MoS2 as confirmed by X–Ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). The improved electronic interaction results in better sensing properties. The high dielectric constant and excellent surface-to-volume ratio of the MoS2 layer make it extremely sensitive to humidity; the Au nanoparticles offer good electrical conductivity and mechanical flexibility in its place. The study tested a respiratory sensor in a simulated environment, finding it more responsive to breathing and quick to return to rest. This suggests potential for the Au-MoS2 sensor in tracking breath states due to its sensitivity and adaptability, promising applications across various fields.