Facile synthesis of polyaniline/carbon dot nanocomposites and their application as a fluorescent probe to detect mercury

Abstract

In this work, for the first time, novel polyaniline/carbon dot (PANI/Cdot) nanocomposites have been synthesized using a simple method. Meanwhile, the bright fluorescence of Cdots is effectively quenched by PANI through fluorescence resonance energy transfer. With the addition of Hg²⁺, the strong binding affinity between Hg²⁺ and the amino groups of PANI makes the Cdots break away and release from the PANI, resulting in the restoration of Cdot fluorescence, which can be used as a fluorescent probe for Hg²⁺ detection. This fluorescence “off–on” signal is sensitive to the concentration of Hg²⁺, and there is a good linear relationship between the fluorescence intensity of Cdots and Hg²⁺ concentrations in the range of 0.05 to 1.0 μM. The detection limit for Hg²⁺ at a given concentration is 0.8 nM. Moreover, it turns out that the nanoprobes represent a rather high selectivity for Hg²⁺ detection. We believe that PANI/Cdot composites will emerge as a new class of fluorescence materials that could be very likely to be suitable for practical applications.