Hybrid photoluminescent material from lanthanide fluoride and graphene oxide with strong luminescence intensity as a chemical sensor for mercury ions

Abstract

Herein, we unveil a novel graphene oxide lanthanide fluoride hybrid nanomaterial. As synthesized Na_xLi_yGdF₄:Tb³⁺ nanophosphor was functionalized with pyromellitic acid (PMA) and 1,10-phenanthroline (Phen) and deposited on the surface of graphene oxide (GO) through a non-covalent approach. PMA and Phen play key roles in improving the photoluminescence intensity and prolonging the lifetime decay of the hybrid nanomaterial. The Na_xLi_yGdF₄:Tb³⁺@PMA@Phen@GO nanomaterial was used for the detection of toxic metals ions such as Hg, Ni, Co, Pb and Mn due to its superior optical properties. The selective and sensitive detection of Hg²⁺ is of considerable interest because Hg²⁺ can cause serious environmental damage and fatal diseases. Luminescent measurements show that the luminescent nanosensor exhibits a selective turn-off response to Hg²⁺ over other toxic metals. Under optimized conditions, the Na_xLi_yGdF₄:Tb³⁺@PMA@Phen@GO sensor could effectively determine Hg²⁺ ions with a low detection limit of 1.03 ppm and K_SV value of 3.65 × 10⁵ M⁻¹. The lower detection limit (LOD) and higher Stern–Volmer constant (K_SV) values compared to the other target metal ions indicate the high sensitivity and selectivity of the fabricated chemical sensor towards Hg²⁺ ions. The fabricated nanocomposite exhibits stronger interaction with Hg²⁺ due to the Phen ligand, thereby disturbing the antenna effect originating from the Phen ligand. The presence of other metal ions does not hinder the detection of Hg²⁺ ions.