Microwave-assisted hydrolysis preparation of highly crystalline ZnO nanorod array for room temperature photoluminescence-based CO gas sensor

Crystallography plane orientation and surface defect on the nanostructure play an important role in optical gas sensor application due to its peculiar quantum properties. In this paper, we report on a formation of highly oriented (002) plane bounded ZnO nanorods ended with a surface defect hexagonal plane, prepared through microwave assisted hydrolysis within 20 s and used as a CO gas detector. A novel photoluminescence-based optical sensor approach was introduced to study the sensor response of the hazardous CO gas as low as 10 ppm at room temperature. The effect of ZnO nanorod arrays prepared by microwave-assisted hydrolysis and hydrothermal was studied towards CO gas response. It was found that the ZnO nanorods prepared through a microwave-assisted hydrolysis approach exhibited remarkable response at 81.1% towards 100 ppm CO gas exposure and showed an ultrafast recovery time of approximately 2.5 min. This provides an excellent sensing approach for operating a low concentration CO gas detection system at room temperature.