Flower-like structured ZnO@ZnIn2S4 for selective triethylamine sensing and mechanism

Introducing defects is an effective strategy to improve the sensitivity of sulfide semiconductor sensors. In this study, ZnO obtained by calcining ZIF-8 was used as the core, and ZnIn2S4 flakes were grown in situ on the outer surface of ZnO to construct a flower-cluster ZnO@ZnIn2S4 composite material with an internal rich S-vacancy. The prepared ZnO@ZnIn2S4 has a well-contacted ІІ-type heterojunction. Compared with ZnIn2S4, the response value of ZnO@ZnIn2S4 to triethylamine gas was increased by 4.9 times, and the response recovery time was shortened from 932 s to 100 s. At a working temperature of 180°C, ZnO@ZnIn2S4 exhibits a response to triethylamine that is 47.2 times higher than the response to other gases, demonstrating its specific selective response to triethylamine molecules. ZnO@ZnIn2S4 can maintain a stable response to triethylamine molecules for a long time in a complex humidity environment. The selective mechanism of material selection was analyzed from the perspectives of molecular attack, molecular polarity differences, and spatial size matching. They are using calcined MOF materials as the core has excellent potential for improving the gas-sensitive response performance of materials. The explanation of the specific selectivity mechanism is positively inspiring for the construction and performance optimization of high-performance triethylamine response materials.