首页|Strong fluorescence quenching of carbon dots by mercury(II) ions: Ground-state electron transfer and diminished oscillator strength
Strong fluorescence quenching of carbon dots by mercury(II) ions: Ground-state electron transfer and diminished oscillator strength
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NSTL
Elsevier
? 2022Mecury(II) ions (Hg2+) detection based on fluorescence quenching of quantum dots is a research hotspot, however, the underlying physical mechanisms leading to their highly efficient quenching remains a mystery. Here, the fluorescence quenching mechanism of the colloidal carbon dots (CDs) by Hg2+ is studied using experiments and time-dependent density functional theory calculations. The results reveal that Hg2+ is attracted by the polarized fluorophores on the CD surface due to the strong attraction force between them. As a result, there arises a Hg2+-dominated unoccupied electron orbital lying below the HOMO of CD by 0.17 eV, which induces efficient electron transfer from HOMO to it and results in formation of charged and slightly separated CD+ and Hg+. This electron transfer along with diminished quantum transition rate accounts for the observed strong fluorescence quenching. These findings highly improve our understanding of the quenching mechanisms of metal ion in solution.
Carbon dotFluorescence quenchingGround-state electron transferMercury ion sensing
Zhao G.、Lu W.、Thuy N.T.D.、Fan J.、Dai D.、Zhang C.
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College of Artificial Intelligence Nanjing Agricultural University
College of Engineering Nanjing Agricultural University
NSTL
Elsevier
