Nanostructured copper sulfide thin film via a spatial successive ionic layer adsorption and reaction process showing significant surface-enhanced infrared absorption of CO2

Abstract

The infrared (IR) gas sensing technique is excellent for CO₂ gas detection systems that require high accuracy and safety standard; however, there is a significant barrier to its application due to its high cost and difficulty in miniaturization. CO₂ sensors that are functional within near- or short-wavelength IR have the potential to reduce this barrier. In this work, a highly sensitive plasmonic material based on nanostructured covellite copper sulfide (CuS), which exhibits desired localized surface plasmon resonance for surface-enhanced IR absorption (SEIRA) throughout near- and mid-IR ranges, was investigated. We prepared CuS thin films facilely in an additive manner based on a spatial successive ionic layer adsorption and reaction process at room temperature. The resulting CuS thin film possesses a structure consisting of hexagonal nanoflakes, and demonstrates significant SEIRA for 100 ppm CO₂ with an enhancement factor of 10⁴.