Colorimetric detection of chemical species based on specially tailored noble metal nanoparticles is garnering increasing interest in the scientific community. The aggregation/dispersion of unmodified or ligand–functionalised plasmonic nanostructures upon binding to an environmental pollutant results in a colorimetric response, which can be easily discerned with the naked eye. This review offers a snapshot of recent advances in this field of plasmonic colorimetry. The identification and detection of anionic, neutral and cationic chemical species among a wide variety of other environmentally significant pollutants remains a particularly important but difficult challenge. The optical transduction of target–ligand interactions at the surface of plasmonic nanostructures via a distinct colour change is very attractive for the development of environmental sensors. Such a litmus test–type colorimetric transduction sensing scheme offers extreme simplicity and excellent robustness for practical applications.
Keywords: plasmonics, gold nanoparticles, silver nanoparticles, visual detection, heavy metals, cations, anions, environmental sensors, plasmonic colorimetry, chemical species, nanotechnology, environmental pollutants, environmental pollution, optical transduction, target–ligand interactions, colour change