Preparation of a high-performance acetone gas sensor based on CdS-CdIn2S4 composite and its application in diabetes detection

A high-performance acetone gas sensor based on CdS/CdIn 2 S 4 (CISS) heterojunction was constructed by hydrothermal method, and the sensing mechanism of CdS on acetone adsorption was investigated through first-principles calculations grounded in density functional theory (DFT). Calculated results show that surface sulfur vacancies on the CdS facilitates the adsorption of acetone molecules, which due to the sulfur vacancy can expose a large number of Cd atoms, allowing the d electrons in the Cd atoms to participate in orbital hybridization with the p electrons in the acetone molecule. The more electrons involved in the hybridization, the higher the adsorption energy for acetone molecule. Experimental results show that the CISS2 sensor has a high response of 1350.45 for 1000 ppm acetone with good selectivity and repeatability. Furthermore, CISS2 sensor has a fast response/recovery time (13.1 s/1.85 s) to 10 ppm acetone at room temperature and achieves a low detection limit of 175 ppb. In addition, CISS2 sensor can distinguish normal people and diabetic patients by detecting the difference in acetone concentration in breath, indicating that the CdS/CdIn 2 S 4 gas sensor has potential applications in the field of personal medical services.