Fluorescent mesoporous silica nanoparticles functionalized graphene oxide: A facile FRET-based ratiometric probe for Hg2+

• PPV@MSN@SRh6G functionalized GO fluorescent hybrid nanoparticles were fabricated.
• GO-PPV@MSN@SRh6G has good PL properties due to prevention of electron transferring from PPV to GO.
• PL sensor allows a quantitative ratiometric detection of Hg2+ in water with a detection limit of 7.1 × 10−8 M.
• Our strategy can open up a new perspective in the design of sensor for metal ions.

This paper reported a facile method for fabricating a functionalized fluorescent graphene oxide (GO) by covalently grafting the amine-modified mesoporous silica nanoparticles (MSNs) containing poly(p-phenylenevinylene) (PPV) and lactam of Rhodamine 6G (SRh6G) inside the channel of MSNs. The resulted GO-PPV@MSN-NH2@SRh6G fluorescent hybrid nanoparticles had a good dispersion and strong green fluorescence in aqueous solution. This hybrid material can be used as a fluorescent ratiometric probe to detect Hg2+ in the water through fluorescence resonance energy transfer (FRET). Upon the addition of only Hg2+ ions, the mission corresponding to the ring-opened form of rhodamine appeared at 550 nm with a simultaneous emission quenching of PPV at 494 nm. This ratiometric fluorescence change indicated that an FRET from the PPV to rhodamine was triggered by Hg2+ ions. The hybrid nanoparticles of GO-PPV@MSN-NH2@SRh6G could be used as a novel fluorescent probe to carry out the quantitative detection of Hg2+ with a detection limit of 7.1 × 10−8 M.