Selective sensing of copper and mercury ions with pyrene-functionalized fluorescent film sensor containing a hydrophilic spacer

► A pyrene-functionalized fluorescent SAM film sensor was prepared and characterized. ► The film sensor exhibits high selectivity and sensitivity toward Cu(II) and Hg(II) ions in the form of inorganic salts in aqueous solution. ► The functional subunits and polarity of the spacer play an important role in adjusting the sensing properties of fluorescent SAM sensors. ► To our knowledge, this is the first fluorescent SAM sensor for Hg(II) ion.