colourless is observed upon the addition of Fe(III) and their absorption spectra is
also studied using UV/Vis spectroscopy for the different concentrations of the
Fe(III) [5].
2.2.3 Aggregation Based Approaches
In colorimetric sensing, in most of the cases these approaches are utilized by the
metal NPs such gold nanoparticles (AuNPs), silver nanoparticles (AgNPs), and
others like platinum nanoparticles (PtNPs) or their complex as they are having the
characteristic property of localized surface plasmon resonance (LSPR). This
Fig. 4 a Overlap of emission and absorption of rhodamine 6G (R6G) and Helicene(5H). b Effect
on UV/Vis spectra of sensor as function of Hg(II) concentration (a) 0 mM, (b) 10.0 mM,
(c) 16.7 mM, (d) 23.3 mM, (e) 36.7 mM, (f) 50.0 mM, (g) 63.3 mM, (h) 83.3 mM (adapted from
Ref. [4])
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