Aggregation induced emission enhancement from Bathophenanthroline microstructures and its potential use as sensor of mercury ions in water

Abstract

Bathophenanthroline (BA) microstructures of various morphologies have been synthesized using a reprecipitation method. The morphologies of the particles are characterized using optical and scanning electron microscopy (SEM) methods. An aqueous dispersion of BA microstructures shows aggregation induced emission enhancement (AIEE) compared to BA in a good solvent, THF. This luminescent property of aggregated BA hydrosol is used for the selective detection of trace amounts of mercury ion (Hg(2+)) in water. It is observed that Hg(2+) ions can quench the photoluminescence (PL) intensity of BA aggregates even at very low concentrations, compared to other heavy metal ions e.g. nickel (Ni(2+)), manganese (Mn(2+)), cadmium (Cd(2+)), cobalt (Co(2+)), copper (Cu(2+)), ferrous (Fe(2+)) and zinc (Zn(2+)). This strong fluorescence quenching of aggregated BA in the presence of Hg(2+) ions has been explained as a complex interplay between the ground state complexation between BA and Hg(2+) ions and external heavy atom induced perturbation by Hg(2+) ions on the excited states of the fluorophore BA.

MINERVA: A facility to study Microstructure and INterface Evolution in Realtime under VAcuum

“…At these higher angles, the out-of-plane layer spacing (derived from the [001] peak position) diverges into two separate peaks. The larger dimension corresponds to a lattice spacing of 10.39 Å, very close to the 10.40 Å value found by Mazumdar et al, 34 but smaller than 10.81 Å identified by Ceolin et al 33 The smaller of the two lattice constants is 9.97 Å, considerably smaller than previously reported values. Given that this large difference in q close to the specular beam arises when we reach the critical angle of the substrate, one possibility is that this distortion is due to refraction at the vacuum/film interface.…”

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