Dy(III)-induced aggregation emission quenching effect of single-layered graphene quantum dots for selective detection of phosphate in the artificial wetlands

Publication date: 1 May 2019

Source: Talanta, Volume 196

Author(s): Shui Qin Chai, Jia Hui He, Lei Zhan, Yuan Fang Li, Chun Mei Li, Cheng Zhi Huang

Abstract

Carbon quantum dots (CQDs), prepared by one-step hydrothermal treatment of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) and triethylamine (TEA), could be exfoliated or delaminated into single-layered graphene quantum dots (s-GQDs) with methanol for the first time, with fluorescence (FL) emission at 500 nm when excited at 417 nm. The s-GQDs, with more sufficient carboxyl groups on the surface than CQDs, could be induced to be aggregated by metal ion dysprosium (Dy³⁺), resulting in aggregation-induced emission quenching effect subsequently. However, the presence of phosphate (PO₄^3-) destroys the Dy³⁺-induced aggregates of s-GQDs owing to the strong coordination between Dy³⁺ and PO₄^3-, inducing the FL emission recovery of the s-GQDs and providing selective detection method of PO₄^3- in the artificial wetlands with the linear range of 0.2–30 μM and determination limit of 0.1 μM (3σ).

Graphical abstract

Carbon quantum dots (CQDs) was firstly reported to be exfoliated or delaminated into single-layered graphene quantum dots (s-GQDs) by mixing with methanol followed by evaporating. The s-GQDs with sufficient carboxyl groups on the surface could specifically be induced by metal ion dysprosium (Dy³⁺) to form aggregates, resulting in aggregation-induced emission quenching effect. However, the presence of phosphate (PO₄^3-) destroyed the Dy³⁺-induced aggregates of s-GQDs, inducing the FL emission recovery of the s-GQDs, which can be used for sensitive and selective detection of PO₄^3-.

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