3-Aminopropyltriethoxysilane functionalized ZnO materials for improving the gas sensitivity to 2-butanone

In recent years, researchers have discovered that self-assembled monolayer functionalized surfaces could improve the gas-sensing performance of semiconductor oxide-based sensors. In the present work, metal-organic framework material ZIF-8 was selected as the self-sacrificial template, and then ZIF-8 materials were calcined at a high temperature to obtain ZnO nanoparticles. Subsequently, the surface of ZnO was modified to install a single layer of 3-aminopropyltriethoxysilane (APTES). In comparison with the pure ZnO-based sensor, the sensor based on 0.5 vol% APTES/ZnO had higher response to 2-butanone. The response has remarkably improved mainly due to APTES molecules capture electrons from the surface of ZnO to widen the electron depletion layer. In addition, the amine (–NH2) group of the APTES monolayer enhanced the specific interaction between the sensing material and 2-butanone, thereby the performance of the sensor was improved. After functionalization with 0.5 vol% APTES, the lower detection limit of the sensor reached as low as 200 ppb, while that of the pure ZnO-based sensor was 500 ppb.