Role of defects concentration on optical and carbon dioxide gas sensing properties of Sb2O3/graphene composites

• Graphene/Sb2O3 quantum dots composites are synthesized.
• Good correlation is observed between the optical and gas sensing properties.
• Fluorescence spectroscopy is effectively analyzed gas sensing mechanism.

Sb2O3 quantum dots (QDs) anchored graphene composites were prepared by in situ chemical route, followed by the subsequent annealing. The chemiresistors in the form of thin film fabricated using composites powder exhibit considerable response to carbon dioxide (CO2) gas. The resulting samples were characterized by X-ray diffraction and electron microscopy for structural and morphological analysis. Ultraviolet–visible spectroscopy was performed to the quantum confinement effect in Sb2O3 quantum dots. Fluorescence spectroscopy was employed to study the dependence of gas sensing response on optical properties and defects density. The chemiresistors shows almost linear response up to 50 ppm CO2. Among those chemiresistors, 1.6 wt% graphene chemiresistor shows the best response. The response and recovery times to 50 ppm CO2 for 1.6 wt% graphene chemiresistor at room temperature are 16 and 22 s, respectively.

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