Hg(II) sensing platforms with improved photostability: The combination of rhodamine derived chemosensors and up-conversion nanocrystals

Abstract This paper reported two nanocomposite sensing platforms for Hg(II) detection with improved photostability, using two rhodamine derivatives as chemosensors and up-conversion nanocrystals as excitation host, respectively. There existed a secondary energy transfer from this excitation host to these chemosensors, which was confirmed by spectral analysis, energy transfer radius calculation and emission decay lifetime comparison. In this case, chemosensor photostability was greatly improved. Further analysis suggested that these chemosensors recognized Hg(II) following a simple binding stoichiometry of 1:1. Hg(II) sensing performance of these sensing platforms was analyzed through their emission spectra upon various Hg(II) concentrations. Emission spectral response, Stern-Volmer equation, emission stability and sensing selectivity were discussed in detail. It was finally concluded that these chemosensors showed emission turn on effect towards Hg(II), with high photostability, good selectivity and linear response.