Optical Ammonia Sensor Based on ZnO:Eu2+ Fluorescence Quenching Nanoparticles

Abstract

Abstract An ammonia sensor is conceived and constructed using the downconverting ZnO:Eu2+ nanoparticles that can be excited by near-ultraviolet (378 nm) light and emit indigo color light. The capability of the ZnO:Eu2+ nanoparticles for ammonia gas sensing was studied from fluorescence quenching measurements. When these nanoparticles were exposed to ammonia gas, a significant luminescent intensity variation of the excitation spectra was observed. The detection limit of the proposed optical gas sensor is 20 ppm with a good linearity (R 2 =0.9759) from 0 to 80 ppm of ammonia. The sensor has the advantages of a simple structure, high sensitivity, easy fabrication, and low cost, and can be used for sensing ammonia gas in factories, laboratories, etc.