A visual photothermal paper sensor for H 2 S recognition through rational modulation LSPR wavelength of plasmonics

It is known that the localized surface plasmon resonance (LSPR) wavelength of plasmonics is highly dependent on compositions and geometry of plasmonics as well as the surrounding environments. Here, monodispersed Au@Ag core-shell nanoparticles (Au@Ag NPs) were prepared by carefully optimizing the shell thickness of Au@Ag NPs, and the presence of hydrogen sulfide (H 2 S) would significantly alter the LSPR wavelength. On the basis of this, a photothermal paper sensor for on-site recognition of H 2 S was constructed with a visual detection limit of 12.8 ng/L.