Photosensitive polystyrene/silver bromide hybrid colloidal crystals as recoverable colorimetric naked eye probes for bromine gas sensing

Abstract

Photosensitive polystyrene (PS)/silver bromide (AgBr) hybrid colloidal crystals were prepared using a co-deposition method. After treatment with UV light, the infiltrated AgBr decomposed to silver nanoparticles (Ag-NPs), and PS/Ag-NP hybrid colloidal crystals with enhanced structural colours were obtained. The enhanced structural colors are due to the absorption of incoherent scattering light and increase in color saturation by the embedded Ag-NPs. The band gaps of the PS colloidal crystals, and PS/AgBr and PS/Ag-NP hybrid colloidal crystals were measured using a UV-vis reflection spectrometer and calculated using Bragg law. The obtained PS/Ag-NP hybrid colloidal crystals could be used as recoverable colorimetric naked eye probes for bromine (Br) gas sensing with a detection limit of 15 mmol L⁻¹ at a sensing time of 50 s. The sensor had a very reliable performance after repeated bromine sensing, and could be mass produced facilely with very low cost.