▎ 摘　　要

Chemiresistors based on graphene-ZnO QDs composite have been fabricated and tested for CO2 detection. Structure and morphology of composites were analysed through X-ray diffraction, high resolution-transmission electron microscopy, and Raman spectroscopy. The optical properties were studied through ultraviolet-visible and fluorescence spectroscopy. The graphene-ZnO chemiresistor exhibits significant sensing response at low operating temperature and it enhanced linearly with addition of graphene. The 80 wt.% graphene-ZnO chemiresistor exhibits the highest sensing response among all chemiresistors, low operating temperature, high selectivity, good stability, and fast response and recovery time. The particle size effect and defects chemistry was employed to analyse the enhancement in sensing response with an increase in wt.% of graphene. Also, there was excellent correlation observed between the defects density and sensing response as a function of wt.% of graphene.