Room-temperature triethylamine sensing of a chemiresistive sensor based on Sm-doped SnS2/ZnS hierarchical microspheres

Abstract

Selective detection of noxious gases at low temperature is imperative in some industrial applications. In this work, pure and Sm-doped SnS₂/ZnS hierarchical microspheres were prepared by a sequential reflux condensation and hydrothermal process. The morphology, crystalline structure, defect density and chemistry composition of the as-prepared samples have been analyzed by SEM, TEM, PL, XRD and XPS spectra. Compared with sensors based on pure SnS₂/ZnS samples, the 3.0 at% Sm-doped SnS₂/ZnS samples exhibited a remarkable enhancement in triethylamine-sensing performance at room temperature (∼20 °C), including higher response, fast response/recovery speed, low detection limit and good selectivity. The improved gas sensing performance may be attributed to the SnS₂/ZnS n–n nanoheterojunction, high crystal defect density, Sm²⁺/Sm³⁺ redox pairs, grain boundaries and gas channels in the sample. In addition, the gas sensing mechanism of the Sm-doped SnS₂/ZnS hierarchical microspheres was also analyzed.