Performance Analysis, Modelling, and Development of a Signal Conditioning Unit of N-Type Metal Oxide Gas Sensor for Acetone Gas Detection.

Metal oxide semiconductors have been widely used in the eld of gas sensor study. Various researches are being done to improve the sensitivity of the sensing material for applications like breath analyzers. In this work, a theoretical investigation and analysis of the n- type metal oxide for Acetone gas detection are carried out. The rate of change of resistance of the sensing material with respect to the change in the concentration of the target gas is analyzed. Acetone being a reducing gas the resistance was found to decrease for n-type material. The simulations were done using COMSOL Multiphysics and results showed that the resistance of the sensing layer varies with the concentration of the target gas. Also, the performance analysis of sensors has been compared with the experimental results. Further, we have also derived a mathematical expression connecting the relationship between the concentration of gas and the rate of change of resistance. The resistance change is observed to be proportional to the target gas concentration. A signal conditioning circuit was also designed for providing a user-friendly interface for monitoring the gas concentration. The simulation of the signal conditioning circuit was done using Proteus Design Suite. This work will aid researchers to define and predict the behaviour of gas sensors.

Fast response acetone-sensing properties of SnO2 nanoparticles prepared by the sol-gel method

SnO2 nanoparticle architectures were successfully synthesized using a sol-gel method and developed for acetone gas detection. The morphology and structure of the particles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The SnO2 nanoparticle architectures were configured as high-performance sensors to detect acetone and showed a very fast response time (<1 s), a short recovery time (10 s), good repeatability and high selectivity at a relatively low working temperature. Thus, SnO2 nanoparticles should be promising candidates for designing and fabricating acetone gas sensors with good gas sensing performance. The possible gas sensing mechanism is also presented.