Fast triethylamine gas sensing response properties of Ho-doped SnO2 nanoparticles

Doping is benefical to the formation of defects on the surface and modification of the electronic structure of metal oxides. In this work, SnO2 nanoparticles (NPs) with different holmium ions concentrations of 0 at.%, 0.11 at.%, 0.45 at.%, and 0.53 at.% have been synthesized by a gas-liquid phase chemical deposition method with following annealing process. The SnO2:Ho3+ NPs exhibit superior triethylamine (TEA) gas sensing properties. The TEA sensing performance of the 0.45 at.% Ho-doped SnO2 NPs based sensor markedly improve compared with other different Ho doped based sensors. The response time for detecting 50 ppm TEA is only 2 s, and the response value is about 12. The as fabricated sensor shows fast response, excellent selectivity and reproducibility to TEA gas at a relatively low working temperature of 175 °C. Gas sensing testing shows that a suitable concentration of Ho doping leads to the enhancement of the sensor response. The enhanced sensing mechanism is attributed to the formation of oxygen vacancies and change of carrier concentration.